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[Articles Home]  [Add Article]  

SDR: Ham Radio of the Future?

Claudio (IT9JCB) on May 22, 2008
View comments about this article!

The Ham Radio future: Software Defined Radio?

This short memory will address a very actual debate: Which is better, a classic full analog receiver, a fully DSP receiver, or a right mixture of them?

From a pure theoretical point of view, my own experience (I'm an engineer and SDR is a daily issue for me) suggest me that full digital must be better because this should be the ideal receiver, the perfect one, but now, let turn on my new FT-950 (which is almost a full DSP receiver), my old TS-930S and an old Telefunken single conversion military receiver designed in the 60s.

Let switch the antenna from A-B-C in a crowded 40m band SSB during the night and carefully listen to they all: who is better, or I should say, who is sounding better and smoothed and quiet?

Very strangely the old Telefunken with its mechanical filters (do you remember the Collins?) is the more pleasant to listen to...why?

Now we'll enter in a very mysterious field, the subjective response: is that receiver really better in terms of noise floor, IMD, dynamic range etc etc. The answer is clearly NO.

FT-950 has 95dB of dynamic range, the TS-930S has a ridiculous 75 dB and the Telefunken has about the same figure. So, why from a subjective point of view many others and me prefer the old Telefunken?

Remember that in SDR like radio as the 950, the key receiver functions are done via a floating point DSP, i.e. in an almost perfect way.

For example the digital filters used in the 950 have an incredible selectivity and shape factor, none crystal filter as good it could be, can surpass the powerful digital filters employed in the DSP. So, where is the bug? Why old analog receivers seem to go better?

The answer can be found going back in the past. In the 80s the first CD players entered in the scene: their sound, compared with analog sources as good tape and turntables where horrible. It was metallic and very disturbing. At that time many audio amateurs claimed that the digital sound would never surpass the beauty of the analog sound.

They where wrong: NOW, be care, just NOW and in the past few years, the digital sound has surpassed the analog one, after decades and decades of technology developments in achieving better and better performances from digital audio sources as DVD and others.

So the answer to the question WHICH IS BETTER: the fully digital receiver (SDR) will be better, for sure, but not NOW.

The radio engineers have to spend lot of their time investigating on why an old 60s receiver sounds so good and probably they will find the right answer, but not NOW: SDR is still too young.

Member Comments:
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SDR: Ham Radio of the Future?  
by WA2JJH on May 22, 2008 Mail this to a friend!
Not yet. Problem seems to be with the programers in JA.
Not many adaptive alogorythms are used.
Result: On the lower end DSP radio's like Yeasu's 950 is that many little tweaks are needed by the op.

Read W4LGH's experiences. He is top notch in operating and developed a few of his custom tweaks for different band conditions. He has also gets the latest programming patches from Yeasue.

The so called xtal roofing filters, just plain suck in the 950.

To a new ham, the 950 will over plenty of bang for the buck.
To hams like myself and others, we think an all DSP radio at a low cost is a tall order.

Some of the older Hybrid DSP/conventional radio's like the Kenwood TS-950SDX was an example of not putting DSP all in one basket.

Just my buck $3.80 of opinion.
 
RE: SDR: Ham Radio of the Future?  
by NV2A on May 22, 2008 Mail this to a friend!
I'm just a "lunch-bucket" type ham here, no special technological skills here for sure.

I had a Kenwood TS 940s and then an Icom 746 and loved the receiver in the 746 better. I ended up selling the 746.

Fast forward about 8 years and I'm getting back into ham radio and bought an Icom 756 Pro III. I think I might buy another 746 (non-pro) as I liked the receiver better? Not sure if it is band conditions/solar flux only or maybe the 746 actually did sound better to me. It was certainly easier for me to operate mobile.
 
RE: SDR: Ham Radio of the Future?  
by W8ZNX on May 22, 2008 Mail this to a friend!
maybe for others but not for me

would rather run old analog tube radios
and solid state qrp jobs

future
maybe

but sdr has no sole, no mystery, no romance

give me a 6AG7 in to a 6L6
and a Drake 2B
any day over so called modern digital/ computer lash ups

yours truly
Mac dit dit
 
SDR: Ham Radio of the Future?  
by KY6R on May 22, 2008 Mail this to a friend!
I agree - I have been a computer programmer since 1981, and SDR feels like the earliest of the early as far as "versions" go. Almost like Beta or Version 1, and you know the joke about Version 1 - "Never Buy Version 1" . . . .

However, I have had an Orion and Orion II, and I can tell you that within a few years Ten Tec has done an amazing job at rapidly improving their software.

I think every one of these radios driven by code takes a couple of years to tweak - and I do think the hams in the field and on the user news groups / Yahoo are the best Beta testers the radio companies could ever hope for. Imagine that - enthusiastic, smart and fully engaged testers. I wish testers of my business software were this "passionate".

The hams in these user groups are WAY better than paid Beta testers, and my hats are off to the hams that "put up with" being a guinea pig - and have to pay for it to boot.

But it is also a fun part of ham radio for many - because the Beta tester does get to see and feel the improvement along the way.

And its a lot like digital cameras a few years back. While sensor size is the issue now - I'll never forget how much better a 4 megapixel camera seemed over my first 1 megapixel camera. 8x10 prints looked good for the first time at 4 MP and beyond.

I think the SDR radios will follow this sort of product improvement cycle. If the hardware is decent, the SDR radio's should improve rapidly in the next few years.
 
SDR: Ham Radio of the Future?  
by KZ1X on May 22, 2008 Mail this to a friend!
Wonder why the top two receivers on Rob Sherwood's reports are US-made SDRs?

#1: Elecraft K3
#2: Ten-Tec Orion II

 
RE: SDR: Ham Radio of the Future?  
by N9DG on May 22, 2008 Mail this to a friend!

For the record the Sherwood ranking order is:

1. K3
2. Flex-5000A
3. Orion II

And I would not use the FT-950 as a basis of comparison or a benchmark for assessing the state of amateur radio SDR today. The Flex-5000A is much more advanced technologically and does a better job of capturing the essence of what SDR is really all about.
 
RE: SDR: Ham Radio of the Future?  
by KD2KU on May 22, 2008 Mail this to a friend!
I think the major problem is to be found in poorly designed audio stages. Everyone’s hearing ability is different and that is where bass and treble controls come into play. Few rigs have that ability.
 
RE: SDR: Ham Radio of the Future?  
by W4LGH on May 22, 2008 Mail this to a friend!
KZ1X said on May 22, 2008..."Wonder why the top two receivers on Rob Sherwood's reports are US-made SDRs?

#1: Elecraft K3
#2: Ten-Tec Orion II "

Maybe, just maybe he's (Sherwood) is a little biased?
And I am certainly not picking on any brand of radios, for that matter, I am giving some serious thought to the new TenTec Omni VII. I love my Yaesu FT-2000 and it has the right mix of Analog and SDR built into the same box. I have watched, listened and tested each version update, and geniune forward progress has been made, and I see a lot more are coming.

However the audio out of either my Drake 4B line, or my Drake TR-7A, is very easy to listen to, using crystal filters, and totally analog..

73 de W4LGH - Alan
http://www.w4kgh.com


 
RE: SDR: Ham Radio of the Future?  
by WT4T on May 22, 2008 Mail this to a friend!
I think one should step back and look at the term SDR, software defined radio means a open every changing software, up gradeable control system ever changing ,to meed the demands placed upon it for what ever the radio operator wants the rig to do. The ft-2000,proII or any other rig that comes pre packaged ie the DSP are a "live with what you have ", no changes or up grades likely to happen ...ever. Untill another model comes along. These rigs should be called software controlled radios. The only true full function SDR RADIO is the flex rigs such as the 5000a. Every day the rig can change to meet the demands required of it and major changes will be made as required. the other SCR radios have to be what they are and in most cases can not be upgraded.
just a thought.
dale wt4t
 
RE: SDR: Ham Radio of the Future?  
by K6CRC on May 22, 2008 Mail this to a friend!
I have been involved with audio since college (in the mid 1970s) and this argument is VERY familiar. The 'purists' refused to yield first from vacuum tubes, then from discrete FETs. This refusal was based on purchasing decisions driven by advertising and magazine articles in the 'audiofool' magazines. Hey, I spent all that money, it MUST sound better.

I have a $50 TriPath-chip digital amp in a cheap plastic case, powered by a wall-wart. Driving a pair of old Klipsch cornerhorns, it smokes my EL-84 boutique amp and my Marantz 8B, the classic tube amp of the 1960s. No comparison. The audio mags cannot make any money on advertising from these cheap amps, so you will see few articles on them.

I am new to ham radio, but I see similar issues. The receiver in my modern programmable DSP Yaesu is clearly superior to a similar rig of a few years ago. Technology does march on. The real question is not about specs, but is about what SOUNDS better to YOUR ears? My tube amps sound 'warm' to my ears, and I enjoy that sometimes. But by any objective or subjective measure, my $50 digital amp is better. It is fun to see the tubes light up, but I have no illusions that the HQ180 can even come close to a modern receiver.

As pointed out, modern SDR will always get better, but old radios are what they are. Use and enjoy.
 
SDR: Ham Radio of the Future?  
by W2RLB on May 22, 2008 Mail this to a friend!
Hello all , The 950 is not a sdr it is an analog radio with dsp as all the dsp radios are . Understand the sdr 1000 and sdr 5000 radios take an analog signal convert it to digital then back to analog thru the sound card and in doing this processes the signal unlike dsp . If you listen to a sdr radio and compare it to your analog radios you will hear quite a difference . The sdr is much more pleasent to listen to . I own and operate an orion , ts 2000 , ft 1000mp , ft 847 , ft 100d , flex 5000 , and have owned sdr 1000 , ft 920 , ft 1000d , 756 pro , collins 75a4 , and many other radios and i can tell you the sdr is unlike any other analog radios i have owned . Many of the flex owners after a short operating time have sold all there analog radios and only have a flex period . I have never found a dsp radio to perform head and shoulders above a non dsp analog radio and dsp radios only display a very slight advantage in certain band conditions never copy and no copy condition . I have found in ab comparisions the sdr 1000 , sdr 5000 , and orion will 100% copy q5 while the analog dsp radios will be 50% or q3 . Dont believe " i can hear everything thats there " unless you have compared the better radios out there when the band is loaded with strong signals . Rich
 
RE: SDR: Ham Radio of the Future?  
by WB2WIK on May 22, 2008 Mail this to a friend!
>RE: SDR: Ham Radio of the Future? Reply
by W4LGH on May 22, 2008 Mail this to a friend!
However the audio out of either my Drake 4B line, or my Drake TR-7A, is very easy to listen to, using crystal filters, and totally analog..
73 de W4LGH - Alan
http://www.w4kgh.com<

::I notice that, too. Regardless of lab tests, when the rubber meets the road (antennas connected, band noise, hundreds of strong signals across the spectrum not just at two frequencies, etc), a lot of analog stuff sounds just terrific and very easy to listen to. After hours of operating my DSP stuff, if I go back to the TR-7 and tune around, my ears go "ahhhhhhhhh...." Ditto tuning around with my now 51 year-old 75A4.

I love DSP flexibility, edge-of-cliff filter response, dial-in modulation response and the amazing stability (virtually 0 ppm from cold) of modern gear but it never *sounds* as nice as the older stuff.

Maybe one of these days.

WB2WIK/6

 
RE: SDR: Ham Radio of the Future?  
by AB7E on May 22, 2008 Mail this to a friend!

This is a very misguided article. It seems silly to broadly criticize SDR radios (which the FT-950 is not) because the audio in the FT-950 was engineered for intelligibility and not for tonality.
 
RE: SDR: Ham Radio of the Future?  
by W4LGH on May 22, 2008 Mail this to a friend!
WT4T on May 22, 2008 said.."I think one should step back and look at the term SDR, software defined radio means a open every changing software, up gradeable control system ever changing ,to meed the demands placed upon it for what ever the radio operator wants the rig to do. The ft-2000,proII or any other rig that comes pre packaged ie the DSP are a "live with what you have ", no changes or up grades likely to happen ...ever. Untill another model comes along. These rigs should be called software controlled radios. The only true full function SDR RADIO is the flex rigs such as the 5000a. Every day the rig can change to meet the demands required of it and major changes will be made as required. the other SCR radios have to be what they are and in most cases can not be upgraded."

I will have to argue this as I think the FT-2000 and the newer TenTecs are SDR, as much as the Flex1000 & 5000's. Anytime the radio is driven by software, it is a SDR. The difference being that the Flex is open source software, and uses an out-board computer to operate it, the FT-2000 has its own processor and the software, at this point is propriatary, but this it will become open source before it is all over.

My hat's off to Flex, as it is a super radio, but I am not ready to have to slave a PC to a box box to operate. Over the past year, and 5 or so software upgrades to my FT-2000, many new features and controls have been added, so by its truest deffination. it is SDR.

I still say DSP has a long way to go in Ham radio. It will come into it own at some point down the line. Its getting better, but!

73 de W4LGH - Alan
http://www.w4lgh.com



 
SDR: Ham Radio of the Future?  
by KB2HSH on May 22, 2008 Mail this to a friend!
I have to agree with the sentiment of the one gentleman that prefers tube gear...just not to that degree.

When in the market for a new rig last year, I had contemplated getting a new Argonaut. Being a life-long QRPer, as well as having owned a Ten-Tec Argonaut 505, the thought of having another one was delightful, to say the very least. That is, until I learned that it was a SDR. I eliminated the Argonaut from my list of possibilities.

Professionally I am a PBX Technician. And every day, I deal with the troubles caused by computers, their lousy software, or their horrid drivers. I don't find the idea of software lockups on my RADIO appealing.
 
RE: SDR: Ham Radio of the Future?  
by WA2DTW on May 22, 2008 Mail this to a friend!
KB2HSH wrote: "When in the market for a new rig last year, I had contemplated getting a new Argonaut. Being a life-long QRPer, as well as having owned a Ten-Tec Argonaut 505, the thought of having another one was delightful, to say the very least. That is, until I learned that it was a SDR. I eliminated the Argonaut from my list of possibilities. "

OM- You're missing out on one great rig. Although the Argonaut V is a DSP rig (and has downloadable firmware), it has the feel of an analogue rig. It has some shortcomings (no RF gain, no downward bandswitching, etc) but is a real pleasure to operate.

73
Steve WA2DTW
 
RE: SDR: Ham Radio of the Future?  
by WA2DTW on May 22, 2008 Mail this to a friend!
KB2HSH wrote: "When in the market for a new rig last year, I had contemplated getting a new Argonaut. Being a life-long QRPer, as well as having owned a Ten-Tec Argonaut 505, the thought of having another one was delightful, to say the very least. That is, until I learned that it was a SDR. I eliminated the Argonaut from my list of possibilities. "

OM- You're missing out on one great rig. Although the Argonaut V is a DSP rig (and has downloadable firmware), it has the feel of an analogue rig. It has some shortcomings (no RF gain, no downward bandswitching, etc) but is a real pleasure to operate.

73
Steve WA2DTW
 
SDR: Ham Radio of the Future?  
by N8KOM on May 22, 2008 Mail this to a friend!
I think that this point has been touched on but not articulated fully in this discussion:

The Sherwood list is measuring and ranking based on technical parameters, which in many, but not all cases, should translate to end user perception of "performance".

But "performance" or end user perception is not driven by technical specifications alone. There are subjective characteristics that a radio has that play directly into the overall feeling of perception of quality and performance by an end user.

So SDR is here, SDR is coming, SDR continues to develop and mature. Like the audio recording analogy, at some point, it may be possible for the SDR to capture and exceed the "subjective" performance of NON-SDR rig characteristics - And this will not be achieved by reaching and then exceeding the technical parameter benchmarks over and over, whithout also taking into consideration the end users ability to translate those (or missing, or yet to be considered) technical parameters into "perception" of performance and quality. It is quite possible to over-design something, but not many people think in those terms.

Steve N8KOM
 
RE: SDR: Ham Radio of the Future?  
by W9OY on May 22, 2008 Mail this to a friend!
With respect to Rob Sherwood I'm not sure Alan knows his patootie from a hole in the ground. If you look at Sherwood's business its about improving friggin DRAKE RADIO'S so to say he has some kind of SDR bias is disingenuous or just shows a lack of knowledge. If anyone is biased its Alan and his constant bilge about how wonderful old radios are. I owned a bunch of Drakes and they were noisy especially in the audio chain their front ends were lousy and the AGC stunk, and nothing had change but the date regarding that. W8JI likes his Drakes however he basically gutted them and rebuilt all the innards. A pretty poor advertisement if you have to gut a radio to make it into something acceptable. I did this to a TS-820 once and I learned a lot about how not to build a receiver in the process.

My experience with Rob is that he is spot on in trying to be objective, especially in his technical analysis and in his advancement of the state of the art.

With respect to SDR it is a multiply defined a constantly moving target. My K-1 has some sort of "DSP" in it. I have used external DSP's and I have used a Pegasus and an Orion, and in my mind none of these save the Pegasus are really SDR in the modern sense. These radio's including the Orion in terms of their SDR capability are pretty much toys. The processor in the Orion is basically similar to a palm pilot or a cell phone, hardly breath takingly inspiring

I presently use the Flex Radio lineup and I think this lineup more than any other in my mind represents a true SDR. The DSP in the Flex line resides on the computer in other words the radio is somewhat analogous to a dual conversion receiver. The first conversion resides in hardware the second in software on the computer. The signal hits the antenna and is direct converted to a baseband which is fed through something called a QSD then to an analogue to digital converter. You can think of this as if the signal is presented to this QSD/ADC and the signal is sliced up into a bunch of snapshots and then fed into the computer memory for further processing.

This is the first conversion is analogue to digital. The second conversion is a digital representation of the signal manipulated in software and then again made analogue and presented to the audio chain for your listening pleasure. The band width of the signal at its presentation to the second conversion is what ever the bandwidth of the ADC is, for example 48K, 96K or 192 khz. This means you have a 192 khz slice of the band and all of the signals contained within to analyze. This is a bonanza. It means if you present the signal to a pan adapter, you can see every signal contained in a 192 khz swath of spectrum. You can point your mouse on any signal of interest and click and bingo you are listening to THAT signal. That means you spend NO time listening to noise, and you know every second where the signals are in that 192khz swath.

Once you choose a signal to listen to, the software builds a filter around that signal of a specified and software definable nature, and it then detects the signal according to the mode you desire, whether LSB or FM or AM or DSB or CW or digital etc etc. As new modes show up, its merely a task of writing new code to decode the mode (ahh the alliteration). The signal is then sent to the audio path. How good is the audio? How good is a 24bit stereo signal? It beats the snot out of ANYTHING else in ham radio period. You want to tailor the audio? Easy there is a graphic equalizer in software just for your desire. You want the signal routed to the headphones? Good, there is a mixer in software to route the audio. You want it to speakers? The mixer can send it there. You want it to both speakers and headphones and that old fashioned reel to reel tape deck over in the rack? Easy the mixer can do that simultaneously. You want to tailor your mic audio? The equalizer can do that too. You too can sound like you live in a cave. You can have 3 antennas connected at once to the radio as well as a separate RX antenna for the beverages, or you can have outboard transverters. If you set up a transverter you can tell the program what the offset is, and which direction the transverter tunes and the readout in the radio will take into account all that data and give you a true readout of the exact frequency you are listening to, and it can do this for every transverter you connect based on the band you choose. It will also precisely limit the power out so if one transverter needs 5 watts and one needs one watt the radio will not over drive. Since the radio is full duplex you can listen to your transmitted signal in the bandwidth of a satellite transponder without a second receiver.

There are built in keyers and both paddle and keyboard and memory keyer and built in and speech processing and audio keyer features for contesting. If you want a 4khz wide ESSB signal you can do that or if you want a 2 khz wide ssb signal you can do that. If you want to control other programs like PSK31 you can use a couple of pieces of software that simulate control cables and audio cables. This means you can hook up your contesting program and have it call CQ and key the transmitter as well as control frequency, or have the DX cluster control the frequency at the click of a mouse with no additional wiring, all done in software.

The way the Flex 5000 works, with the addition of the second receiver, is you can actually run 2 radio single op (SO2R) from the single Flex 5K The reason is the Flex 5K runs 3 simultaneous processes which are on all the time. The radio is not half duplex like most transceivers it is full triplex so you can listen on 2 separate bands and even transmit on a third band all at once. Try that with your Yaesu or Kenmore. The radio without the second receiver is full duplex and it has built in the software presently 2 receivers so you can work split. This can be expanded to up to 16 receivers those one wonders how you would listen to 16 receivers. IN other words if you can think and you can write the code you can do it. It is NOT hardware limited except in the grossest of senses. In fact at the present time it is our imagination that limits the radio, not the radios capability.

We are largely bound by the notion of KNOB and serial one dimensional processes. That is our experience. The radio can be made to do multi dimensional data presentation and it can be made to respond to parallel inputs. This presentation of the software does not presently exist, but it could in the near future. There is nothing that precludes this from being implemented. For example lets say you are in VHF contest. You could have the radio displaying half a dozen bands on half a dozen pan adapters, with audio spaced around various points in the shack, and have the audio of the pan adapter in focus presented to the speaker set in front of you all based on where you point your mouse or perhaps some kind of midi surface controller or a game controller. Instead of making the interface to look like a radio. You may want it to look like a fighter jet where signals are presented like bogie's to be picked off in a contest You could program your antennas to respond automatically and have the radio sequence preamps etc as you squeeze the PTT. All done in a million lines of software, all done in a software defined radio, and all extremely plastic and amenable to change. If you don't like the way it works and you have the first clue about coding, you can rewrite the code and make the radio do what YOU want it to do. The company does not hold you hostage to what they think a radio should be. There are several independent threads of coding going on for the flex line, written by people what have particular interest and as good ideas are developed these are included in the main trunk. The software is updated almost daily on something called the SVN and you can down the most bleeding edge version, or you can use the release version, or you can have a dozen different version all residing on your computer available for you use at the click of your mouse. If you have both a SDR-1K and a Flex 5K you can run 2 totally separate SDR radios at once. I commonly use one radio for rag chewing on SSB while using the other to zip around working DX on CW on various bands. I use an Acom amp and my antennas are auto switching so I can ragchew with the boys on 75 while breaking some pileup on 40 or 160 CW. It satisfies my ADD.

There is a program called CW skimmer that the raw 192 khz baseband signal can be fed to and that program will define and decode every CW signal on the bandwidth fed to it. Click on the station you want to work and the radio comes up on freq ready to have a QSO. If you knew the callsign of every signal on the band imagine sitting in the cockpit of your radio fighter jet picking off the multipliers while the jokers with their KNOBS are getting their clocks cleaned. If you knew the callsign of every signal on 2 or 3 bands you could use some kind of neural net software to order those callsigns in a way that would give you the greatest advantage of working them according to some statistical modeling. If you think it you can do it.

So to answer the question: "SDR ham radio of the future?", the answer is no. It is the ham radio of the present. All that other crap is dead and dying ham radio of the past. If that's too in your face go play with your KNOB.

73 W9OY
 
SDR: Ham Radio of the Future?  
by KY6R on May 22, 2008 Mail this to a friend!
After sitting in front of a computer all day programming, the last thing I want is a computer front-ending a radio. I also don't want a ton of cables between a computer and my radio.

For DX-ing, the ability to separate the noise from the signal and separate close in signals is where its at for me. Many rigs do this very well these days - and a few in the "under $2000.00" class. The Ten Tec Jupiter is one example.

Its funny that someone mentioned the Ten Tec Argonaut V. Now there is one little radio that I swear sounds as good as some of the best tube radios I have used in the past. It may not have all of the QRM and QRN filtering controls, but it does have one heck of a great sound.

In fact, just for "fidelity", I like the Argonaut V's sound better than the Orion II, but for DX-ing in the nasty pileups - its the Orion II.

The FT-2000D also has a very nice sound - even though it might not be ranked as high as some of the other rigs by the technical testing labs.

In the end - you have to be able to use the right hammer for the job - and the radio that has your required feature set and good sound is the radio that is right for you.

Since our ears vary, I expect the "best rig" will vary person to person.
 
SDR: Ham Radio of the Future?  
by N5EG on May 22, 2008 Mail this to a friend!
Phil Harmon, VK6APH gave an exceptionally good paper about SDR at Dayton this year. He looked at how close to the antenna could the ADC be placed? His conclusion is if you have about $55,000, you can put it right there. If you have $100, then not so close.

He showed how to achieve about 121 dB of dynamic range using the $100 dollar device, switchable analog RF bandpass filters between the antenna and the ADC, and an FPGA to digitally down-convert / decimate / CIC filter the samples. That's not half bad.

Also, he showed how 3rd-order intercept is not a meaningful measurement when using an ADC. Because of how ADC's work, the number is worse at low input signal levels, and much better at high input signal levels. He also discusses dithering the ADC to improve the spurious-free dynamic range.

If you have a technical interest, I highly recomend reading through Phil's slides. TAPR was supposed to have a link to the presentations, but it's not there right now. If I can find it, I'll post the link.

-- Tom, N5EG


 
RE: SDR: Ham Radio of the Future?  
by IT9JCB on May 22, 2008 Mail this to a friend!
To all and N9DG...

Don't be surprised about the K3 (yes I agree it's the best) but it's not a true SDR radio: if you look to its diagram you will find a superb crystal filters set (8.215 MHz) just after the first conversion. So it's more like an analog one.....

73s Claudio
 
RE: SDR: Ham Radio of the Future?  
by IT9JCB on May 22, 2008 Mail this to a friend!
AB7E wrote: "This is a very misguided article. It seems silly to broadly criticize SDR radios (which the FT-950 is not) because the audio in the FT-950 was engineered for intelligibility and not for tonality.".........

I used the FT-950 as example but I've also tried many other modern radios (as the FT-9000..IC7800 etc). My intention was not to criticize SDR radios...on the contrary I love them....a lot (I'm just designing one for my company).
The main issue of the article concerned about the listening pleasure, so I strongly encourage US and Japanese engineers to use users feedback to improve their products in such a way that one day we all could state: digital is better for sure !!

73s Claudio
 
RE: SDR: Ham Radio of the Future?  
by WB2WIK on May 22, 2008 Mail this to a friend!
Problem is, just because it bench tests well, will it really fly?

SDR or not, "performance" measurements don't always tell the story.

Here's an example: I had a Flex SDR1000 for six weeks. It was fun to use, although it did require my purchase of a $300+ sound card I did not already have.

Now, for "performance." The SDR1000, like many other rigs I've tried at home, couldn't deal with the 1.5 MW e.r.p. signal from KVOH, a SW BC station very close to me (and also aimed at my location). No matter what I tried, the BC signal created images or artifacts in the amateur bands (it transmits on 9.975 MHz and 17.775 MHz, just below 30m and 18m). I did contact the factory and tried some stuff, nothing worked. It's a hardware issue.

Under identical conditions (same antenna, same everything else), my 30 year-old TR-7 handles the BC signal just fine: No artifacts, no images, no evidence the BC station's even on the air, until I tune across it, or within a few kHz of it.

Admittedly, this is a *really* strong signal, probably about equivalent to an amateur station operating just outside the ham bands with 1500W carrier about a city block away. But it's really there, and the station's been on the air many years, and because it's just outside two major HF bands it's not so easy to eliminate. (Coaxial stub type traps aren't nearly good enough, the Q's not there, even with hardline. I haven't tried a very high-Q L-C circuit trap, feeling, "Why should I have to?" when my older gear has no issues with this condition.)

I'd like to try to SDR5000 to see if it does better in this regard.

To me, a rig can be the greatest thing in the world but if it doesn't work at my location it doesn't do me much good. The problem is completely transparent to the old TR-7.

WB2WIK/6
 
RE: SDR: Ham Radio of the Future?  
by W4RCY on May 22, 2008 Mail this to a friend!
Sherwood ranks the receivers by "Dynamic Range Narrow Spaced". If you read the reviews by Rob and his articles relating to analog vs digital. You will discover that he is yet to find the perfect digital radio. My K2 had a great receiver, but I found ssb to be quite rough on the ears after listening a while. My 1990 Icom Pro 765 is ranked #8 and is much more pleasurable to listen to. It is too bad that we can no longer purchase a new radio that has such a combination of sensitivity and mellow sound. I hope a digital radio with such capabilities arrives on the market. I only have two 765 and parts availability are almost nil.
 
SDR: Ham Radio of the Future?  
by G3SEA on May 22, 2008 Mail this to a friend!
YES !

It's an inevitable technological progression.

KH6/G3SEA
 
RE: SDR: Ham Radio of the Future?  
by AA4PB on May 22, 2008 Mail this to a friend!
When we get to the point where the antenna connects to an analog to digital converter and everything from there on is done with ones and zeros they we'll have a true Software Defined Radio. Right now every "SDR" has an analog front end and only gets converted to digital at some lower IF (or audio) frequency. The fact that even the Flex units plug into a sound card should tell you that the digital processing is being done at a pretty low frequency.

 
RE: SDR: Ham Radio of the Future?  
by N5EG on May 22, 2008 Mail this to a friend!
Here's the link the SDR presentations given at Dayton this year (thanks to Scotty Cowling, WA2DFI).

http://www.hamsdr.com/StartHere.htm

-- Tom, N5EG


 
RE: SDR: Ham Radio of the Future?  
by N4RLL on May 22, 2008 Mail this to a friend!
YEAH!!! What W9OY said.

-- N6EY
 
SDR: Ham Radio of the Future?  
by KG6YV on May 22, 2008 Mail this to a friend!
OK, its probably a given that new technology evolves to being superb after iterations of development. I liked the CD analogy but I have one closer to home for most hams.

I owned several of the fist HF rigs with "synthesizers".

I still own and love my Kenwood TS 940SAT, but the phase noise that I hear as white noise really sucks compared to my new Yeasu FT-2000 OR even my FT-1000D which was a "mature" synthesized rig.

If man evolved to where he is today, maybe SDR's are about at the stage of maturity that man was when he discovered metal, no, wait maybe SDRs are evolving faster. Ok, maybe they are about where man was when Newton wrote his laws of physics.

I guess we won't be launching an SDR to the moon for a while. it took 400 years from Newton's work to Apollo.


Greg
KG6YV
 
RE: SDR: Ham Radio of the Future?  
by AF6IT on May 22, 2008 Mail this to a friend!
Will the PERFECT radio EVER arrive? Won't our expectations continue to climb as the level of technology increases? Wouldn't we find a reason to gripe now matter what they offered us?

The current state of radio performance is excellent! Sure there is room for nostalgia, but the IF DSP rigs do perform quite well indeed- no comparison at all. And they will continue to be refined.

The REAL issue to me for the new breed of rig is not audio quality at all; ERGONOMICS and LONGEVITY are my concerns. Blasted nested menus and lack of quite sufficient detail, particularly on the part of the import manufacturers leave me a little disappointed. That and how the mean life expectation of most of the newest rigs is less than ten years (ultimately affecting resale value even if you do plan on upgrading frequently).

But I like much of what I see in Ten Tec's approach, and also in the amazingly low prices of some of the newest entry level rigs (an omen of what is to come as a result of modern manufacturing efficiency I hope!). So I still find reason to be encouraged. I could overlook a lot indeed when entry level IF DSP HF-6m rigs cost in the low $600's! I hope and suspect we will soon witness this trend break into the mid level rigs. What was once an $1800 dollar rig is now below $1500 and hopefully on the way to $1000 or slightly under as new rigs with fewer but more capable components get rolled out. That will render a bigger & better bang for the buck than EVER before.

And while the old classics may be getting harder to find parts for, they will continue to be admired & enjoyed much as the muscle cars of the 60's do, quite unlike our more recent cars & ham radios. At least they CAN live on! Each has its place, but each plays a different role which simply cannot be equaled by its counterpart of opposite generation. I for one am not willing to sacrifice the advantages of an IF DSP rig, (or of my 4 cyl Acura) at least not for my everyday rig.

AF6IT
 
RE: SDR: Ham Radio of the Future?  
by AB7E on May 22, 2008 Mail this to a friend!

AA4PB: "Right now every "SDR" has an analog front end and only gets converted to digital at some lower IF (or audio) frequency."

For ham radio, that is certainly true, but SDR radios already exist at least in the government arena that directly sample almost to a GHz, possibly even above.
 
RE: SDR: Ham Radio of the Future?  
by W7ETA on May 22, 2008 Mail this to a friend!
Thanks for an interesting article.

Many years ago, I heard a song "Que Sera Sera".

Fortunately, there is a place in ham radio for one tube 6L6 xmitters and SDR rigs.

73
Bob
 
RE: SDR: Ham Radio of the Future?  
by DIPOLE on May 22, 2008 Mail this to a friend!
My money is always on my Drake R7A. The other rig in the shack is a Yaesu with lots and lots of DSP, fancy LCD graphs, diversity receive, etc. and cost $$,$$$. But I'm always drawn back to the Drake for just pure listening pleasure.
 
SDR: Ham Radio of the Future?  
by KA0W on May 22, 2008 Mail this to a friend!
I much prefer what comes out of my TS-850S and FT-1000D when compared to my Orion II. I can listen to the non-SDR rigs much longer, they have a more natural sounding receiver. As for the ultimate receiver specs, most ops will not appreciate the "best" specs, especially the ops on phone where wider IF bandwidths are needed. I have a preference for the pre IF DSP rigs, just a better feel and better "listenability" for my ears.
 
RE: SDR: Ham Radio of the Future?  
by KQ9J on May 22, 2008 Mail this to a friend!
You mean if I get an Flex-5000 I can't sit here and play with my knob anymore?
 
SDR: Ham Radio of the Future?  
by K6YE on May 22, 2008 Mail this to a friend!
Claudio,

Nice stimulating article.

Lee, W9OY, made some very nice comments.

I was conversing with K6AER, Mike Higgins, about the newer radios and he mentioned great things about the Flex, K3, and Orion but not the FT-2000D or the 950.

As someone said previously, "each user has an opinion."

I still have a Yaesu FT-1000D, and Icoms IC-756 and IC-775DSP. My favorites are the 775 for SSB and the 1000 for CW. IMHO, SDR sets are great, with tons of features, totally upgradeable, and are a lot less expensive than the FT-9000 or IC-7800 but after 47 years as a ham, I still like knobs (and Drakes).

I enjoy surfing the bands with a tuning knob. I was an engineer for 36 years, did Tier-3 tech support, and wrote application programs for a Telcom. When I got home after 10 hour days and flipped on the radios, I found that I did not have a desire for lots of menus or keyboard communication work. It is and was iambic paddles and/or a microphone and manually turning the tuner.

I think ham radio is great in that there is at least one interesting aspect, out of many, for nearly anybody with an interest. The same can be said for rigs, antennas, amplifiers, etc.

Have fun and enjoy!!!

Semper Fi,

Tommy - K6YE
DX IS

 
SDR: Ham Radio of the Future?  
by VE6TL on May 22, 2008 Mail this to a friend!
A few months ago I saw a TV show that asked the question, "Are digital recording studios as good or better than the old analog studios that recorded everything to analog tape?" They used a "double-blind" scientific approach to find out. First, it appears that there is only one truly analog "world class" recording studio left in the U.S. (in L.A.) and it went head to head against a "state-of-the-art" digital recording studio. They used a number of "experts" in the recording field (I can't recall the exact number, but each one has wonderful credentials). A live band was recorded and played back with alternating sound bytes, known only to the engineers as to the origin (analog or digital). The bottom line clearly was that it was impossible for these experts to tell the difference. With all the arguments pro/con SDR for amateur use, why not do a similar experiment? I would suggest it could be done using both "on-air" signal sources and carefully controlled laboratory conditions (synthesized signals). In this way the human ear could decide which equipment works better. To make the test fair, one person would have to control the radio and the other would only be allowed to listen with a blindfold on. Ultimately, I believe the best of today's technology would win out (SDR).

Jerry, VE6CNU
 
RE: SDR: Ham Radio of the Future?  
by KB4QAA on May 22, 2008 Mail this to a friend!
<<I guess we won't be launching an SDR to the moon for a while. it took 400 years from Newton's work to Apollo. :>>>

Good news: you are wrong! The HPSDR group is developing an SDR system for use in future Suit-Sat launches from the International Space Station. They are planning to have it operational around the end of 2008.

FWIW, radios with DSP are NOT Software Defined Radios. Having a prefilters does not change the fact that the Flex Radios ARE fully software defined.


B.
 
RE: SDR: Ham Radio of the Future?  
by W4LGH on May 23, 2008 Mail this to a friend!
W9OY said..."With respect to Rob Sherwood I'm not sure Alan knows his patootie from a hole in the ground. If you look at Sherwood's business its about improving friggin DRAKE RADIO'S so to say he has some kind of SDR bias is disingenuous or just shows a lack of knowledge. If anyone is biased its Alan and his constant bilge about how wonderful old radios are. I owned a bunch of Drakes and they were noisy especially in the audio chain their front ends were lousy and the AGC stunk, and nothing had change but the date regarding that."

Oh yes, I know the difference, and I didn't say Sherwood WAS biased, I said maybe he was biased? Also if you are such a lover of Rob, then you'd know that he thinks the AGC in the old Drakes are GREAT!

I own both NEW and OLD, and I truly enjoy my Yaesu FT-2000. What I have said about the old is I enjoy the AUDIO quality from them. I have never said that I would give up the NEW completely for the OLD. However I could be very happy , if I had to give up all of my radios, to keep the Drake TR-7A.

I have said that ,in my opinion, DSP in Ham radios have a long way to go, before being truly astounding. Some of the features in DSP work very well, while others fall off quickly. Being a data engineer, I certainly believe in digital format. Once in digital those 0's and 1's can be completely edited, anyway one sees fit, but in order to interface back to the HUMAN world, everything MUST come back to analog.

I like what one writter said, that performance is one thing, but it is how the end user relates to the overall operation of the radio, as to whether it is a great radio or not. I have no need or desire to DIG out the 1x1 signal in the noise and work him. It won't change my life at all. I'll catch him when the band is better.


73 de W4LGH - ALan
http://www.w4lgh.com

 
RE: SDR: Ham Radio of the Future?  
by ZENKI on May 23, 2008 Mail this to a friend!
While many appear to be impressed by SDR receiver design, the other side of the SDR coin is the transmitter performance.

Many SDR transmitters have high levels of spurious products around their transmit signals. While it is nice bragging about all the high levels of receiver performance being achieved, its disappointing seeing so little attention being focussed on the transmitters performance. After all today its the poor state of transmitter design that is limiting most of us from exploiting such high receiver performance numbers.

The state of SDR transmitter design is poor and most SDR transceivers are not exploiting advanced adaptive methods for IMD and spurious cancellation that we see in many advanced military and commercial SDR designs. The ADAT transceiver might be first ham design to use these advanced design techniques.

While the current state of poor transmitter IMD and occupied continues, trying to squeeze more performance out of receivers is becoming a exercise of peeing into the wind and it might be even be an exercise in futility. Lets get the ball rolling in trying to convince ham radio manufacturers to start producing excellent transmitters. Its sad to see that the 3 top radios on Sherwoods list all have transmitters with poor IMD and ALC performance.
 
RE: SDR: Ham Radio of the Future?  
by KD8K on May 23, 2008 Mail this to a friend!
> FWIW, radios with DSP are NOT Software defined
> radios.Having a prefilters does not change the fact
> that the Flex Radios ARE fully software defined.

That is a interesting question to me, how do you define what is a "software defined radio"? Radio's such as the K3 and the Orion do have a analog to digital converter to convert the signal to a digital format, a processor which provides for filtering, detection and AGC, and a Digital to Analog converter which converts it back to a analog format. To me, this has at least some elements of being "software defined". The main difference I can see is that the Flex does the processing on a external Windows XP computer rather then internally with a processor inside the radio, and the use of roofing filters inside the Orion and K3, which improves wide spaced dynamic range numbers, because of the limited dynamic range of current analog to digital converters.

73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by AD3G on May 23, 2008 Mail this to a friend!
I must agree with Alan, W4LGH. Working a weak signal squeezed in between two huge BC signals is not the most important factor for me.
Rob Sherwood rates his receiver performance by dynamic range,narrow spaced,in which mostly new but some older rigs are at the top of the list.
He also writes about the "ticks ,clicks & pops" in DSP based radios,which are AGC issues you won't find in older non-dsp radios.
Personally, I love my Icom 775DSP and Yaesu FT2000,but I find the audio from my TR7 to be more pleasant if I'm going to be listening a long time,it's less "fatiguing" to my ears,no to mention the clicks and pops DSP introduces to the audio that is absent in the TR7.
To get back to topic,SDR is certainly the wave of the future I'm sure,but it's going to be few years before it gets to it's full potential,which it currently isn't even close to yet.
 
RE: SDR: Ham Radio of the Future?  
by AB2KT on May 23, 2008 Mail this to a friend!
It's amusing that these analog-vs-digital arguments always compare the highest-end systems. Comparisons like that completely miss what is ultimately a much more important test: the one at the *low* end.

A $100 digital playback system is vastly superior to any $100 analog system. I would happily take bets on an A-B comparison between a $20 MP3 player and a $20 cassette player.

Similarly, for its purpose, a $30 SoftRock TRX will outperform radios costing 10 times more.

Part of what makes digital technology important is the level of performance it makes available to *all* users, not just the ones in a position to chase after the best possible performance.
 
RE: SDR: Ham Radio of the Future?  
by AB0WR on May 23, 2008 Mail this to a friend!
ab2kt:
<<<<<<<<<<It's amusing that these analog-vs-digital arguments always compare the highest-end systems. Comparisons like that completely miss what is ultimately a much more important test: the one at the *low* end.

A $100 digital playback system is vastly superior to any $100 analog system. I would happily take bets on an A-B comparison between a $20 MP3 player and a $20 cassette player.

Similarly, for its purpose, a $30 SoftRock TRX will outperform radios costing 10 times more.

Part of what makes digital technology important is the level of performance it makes available to *all* users, not just the ones in a position to chase after the best possible performance. >>>>>>>>>>>>>>>>>

Very good observation!

tim ab0wr
 
RE: SDR: Ham Radio of the Future?  
by N3EVL on May 23, 2008 Mail this to a friend!
<<I guess we won't be launching an SDR to the moon for a while. it took 400 years from Newton's work to Apollo. :>>>

Implying that it will take another 400 years to do this? Not even close! Progress in technology is *exponential* so you won't have long to wait.
 
RE: SDR: Ham Radio of the Future?  
by K4PDM on May 23, 2008 Mail this to a friend!
"If you don't like the way it works and you have the first clue about coding, you can rewrite the code and make the radio do what YOU want it to do. The company does not hold you hostage to what they think a radio should be."

I beg to differ. The SDR user is indeed being held hostage in this manner. He is held hostage to a box that is operated by mouse, keyboard, and interfaced with a computer monitor.

That's my idea of what a computer should be. A radio is something different. And my hobby just happens to be radio. [wink]
 
SDR: Ham Radio of the Future?  
by W2WO on May 23, 2008 Mail this to a friend!
Like most of us, I have had both. My current rig is an Orion.

I agree that the audio from the older rigs was easier on the ears. (My favorite was an HQ-170.) In all technical measurements the new digital rigs are ahead, but there are subjective factors that do not appear in the measurements. Perhaps the audio is too good today, and some us prefer older circuits/components that lost some of the faster transients. (Bass and treble controls do not accomplish quite the same thing.) I wonder how much design attention goes into "comfortable" audio, as a separate design topic?

Bill - W2WO
 
RE: SDR: Ham Radio of the Future?  
by W9JCM on May 23, 2008 Mail this to a friend!
Ok how is a FT 950 related to a SDR radio??? Software Defined Radio......... Flex Radio, K3 maybe a Ten Tec can go in the mix but in no way has the big 3 made anything that resembles or is close to any software definition.
 
RE: SDR: Ham Radio of the Future?  
by W9JCM on May 23, 2008 Mail this to a friend!
Yes "Sherwood" had it out for Flex Radio thats nothing new. And man they are having some issues with that K3.
 
SDR: Ham Radio of the Future?  
by N3QE on May 23, 2008 Mail this to a friend!
A couple of points here:

1. Many SDR's with technically excellent specs really suck rocks when it comes to user interface. Maybe younger guys than me think that menu buttons and LCD screens are the best way to tune through a band. But I don't think so, give me knobs any day!

2. There is a certain appeal to really really simple receivers. Some love direct conversion receivers. Others (me) love single-conversion receivers. All the processing and filtering in a 3-conversion + DSP radio add a certain level of audio "mush" to the output that is not well represented by specsmanship.

Note that my points don't really say anything about SDR vs other radios... it has to do with simplicity and directness of user interface and conversions vs specsmanships. Same things apply to lots of other things in radio, electronics, life!

The user interface issues certainly apply to a large number of non-SDR radios. When I read a QST review and in the first couple of paragraphs the reviewer is talking about mode setting page 78 option 3 and how it interacts with mode setting page 44 option 7, I'm pretty sure that it's not the radio for me :-).
 
RE: SDR: Ham Radio of the Future?  
by AC7CW on May 23, 2008 Mail this to a friend!
I think we "imprint" on whatever type of radio we start off with. I started hamming doing CW with a regenerative pre-WW2 navy receiver and voice was all AM in those days. I've never 100% liked the sound of radios since then, especially SSB!! I have to use a graphic equalizer and am constantly playing with it to adjust the audio.

I bought one of the old regenerative radios I had originally a couple of years ago and I want to put it on the air now just to see if it sounds "better"!
 
RE: SDR: Ham Radio of the Future?  
by AC7CW on May 23, 2008 Mail this to a friend!
Another "imprint" thingy, I enjoyed hamming more with my Heathkit radios than any others. Looking at the specs, there is no reason to believe that those radios were going to be the best by far but I remember operating with them as being fun. I have an SB-102 with all of the available accessories, waiting for a refurb, we are relocating and I'm going to do that work when things settle down. I was trying to figure out what the appeal of an SB102 was to me and finally I realized that 99% of radios are butt ugly!! That 102 is visually maybe the most pleasant to look at and operate as an operater. I worked as a tech for decades and one thing I learned, the engineers don't know ugly from beautiful and they don't care, maybe that's why so much electronics stuff is ugly. I'm a photographer and seeking "beautiful" all the time. I'm going to get another 102 and build a SDR radio into it and see if that doesn't "sound" better...
 
SDR: Ham Radio of the Future?  
by WA0ZZG on May 23, 2008 Mail this to a friend!
Those of you that have kept up with the current crop of software radios, would you suggest it may be time to upgrade? I have an early 90's FT-1000D that I have cleaned, aligned and installed the Inrad roofing filter. It has every filter position filled in both receivers. It is also the last radio that I may be able to maintain on my own.
Dave
WA0ZZG
 
RE: SDR: Ham Radio of the Future?  
by W4IA on May 23, 2008 Mail this to a friend!
Personally I prefer a rig with a rf gain control and some attenuation. Then I can shut off the AGC and ride the RF gain if a strong adjacent station attempts to pump the AGC and desense everything. A lot of people don't know how to use the RF gain, IF shift/PBT, AGC, and expect crystal filters and/or DSP to do everything. The operator still has the ultimate control. If the radio is analog, you have a series of knobs. If true SDR, there is the mouse.

The manufacturers assume you know how the RF gain, shift, etc., works and there is no longer a nice explanation of what you can do with each function.

Oops, excuse me, my rig just EMailed me that it worked 9A2ZH and Z38C on 50 mhz while carrying on a conversation on Southcars, printed the QSL cards, mailed them, and posted the QSOs to Log Book of the World.

Boy, is this fun! Wish I had more time to ham.

 
RE: SDR: Ham Radio of the Future?  
by IT9JCB on May 23, 2008 Mail this to a friend!
To K6EY et all...
I'm really impressed on how many comments I've got back writing this short article, it's really a challenge to read and analyze all the opinions but summarizing I've realized as follows:

- there are white and black...and some gray ones. Analog lovers, fully digital lovers and midway.

- the guy with the strong BCL problem on SDR-1000 is an evidence that a fully SDR radio with an analog to digital converter attached directly to the antenna is not still possible with the todays technology.

- Many hams still prefer the sound of their old style radios but there are also many SDR-5000 fanatics.

My personal opinion about the sound is that many rigs are not well designed in the audio stages, if you look to the diagram of a $10000 rig you'll see that the budget for the final audio PA is about $1...!!!

For which concern the perfect SDR which should be a true SDR with the pleasant sound of an old tube type receiver hereafter is reported the "magic" combination that I'm addressing for my own project:

* An ultra-narrow passive pre-selector "pin diode" tuned over 1.8-30 MHz.

* A 14-bits high speed ADC sampling >80 MHz.

* A digital signal processor based on FPGA and DSP

* An old-style, audio, digital to analog converter and associated filtering, as the ones used in high-end audio.

* A tube based audio power amplifier, at least 10W out.

* A complete set of adaptive DSP algorithms "hears based".

Science Fiction...???

73s Claudio
 
RE: SDR: Ham Radio of the Future?  
by KI4WGI on May 23, 2008 Mail this to a friend!
I also considered AC7CW's approach....I have 2 "junker" HW-101's and have considered placing a softrock RX/TX in place of the IF & exciter of one of them. However, to start I'm going to add an IF jack out on my "good" one and and work out the bugs on the receive end first.

Although I love old boatanchors...a Navy TCS receiver is one of my next restoration projects, I also enjoy the other extreme too!

As long as you can get on the air and make contacts (without trashing anyone with QRM!) than who cares how you do it!

73's
Steve
 
RE: SDR: Ham Radio of the Future?  
by AK2B on May 23, 2008 Mail this to a friend!
It seems to me that there is some confusion as to what really is an SDR. My idea of an SDR was the original Flex SDR-1000. I think I was wrong. It appears that an SDR is any radio that has substituted functions that were once done in hardware with functions that are now done in software. Most notably, things like modulation/demodulation and various forms of filtering fall into that category. Because the software/firmware to do this lies inside the radio instead of an external computer makes no difference in what constitutes an SDR. Also, at what stage in the radio the DSP is located makes no difference. The Flex radios take I and Q information (using a Quadrature Sampling Detector (Tayloe Detector)) right from a direct conversion receiver and passes the audio information along to a computer for processing. The K3 uses a standard 8Mhz IF and a 15KHz second IF straight into a DSP instead of a computer. There are other radios on the market that pretty much work the same way. You may already own an SDR and just don’t know it. Arguing the merits of one method over another is kind of pointless. You can have it either way. Personally, I like having a box that doesn’t need anything more than an antenna, power supply and paddles. Sometimes though, it’s fun to play with those little SoftRock radios.
As far as Elecraft not caring about the audio quality of the K3, that is definitely not the case. The radio sounds great - as good or better than anything I have ever heard, including my R4B. And, recent changes to the transmit firmware, from what I understand, have put it up there with the best ever. I think the designers of the K3 intend to keep it at the top of the list.
Isn’t it nice to see three American manufactures at the top of Rob Sherwood’s list? I suspect that the big three Japanese companies are not going to sit on their thumbs and let this pass unnoticed. Things could get interesting.

Tom, AK2B
 
RE: SDR: Ham Radio of the Future?  
by WB2WIK on May 23, 2008 Mail this to a friend!
Claudio, I like your idea.

Of course if we really wanted the rig to be bullet proof and more user serviceable, we could use 6146s in the transmitter P.A.

No kidding. Cheaper than solid state, more robust, more forgiving, will survive lightning storms better...could power from HV DC:DC converter that would only cost about $50.

SDR typically implies modern solid-state stuff doing the work, but it doesn't have to be that way.

WB2WIK/6
 
RE: SDR: Ham Radio of the Future?  
by W4VR on May 23, 2008 Mail this to a friend!
Some hams with SDRs tell me it's a "work in progress." So, perhaps there is a future for these radios.
 
RE: SDR: Ham Radio of the Future?  
by WD0CT on May 23, 2008 Mail this to a friend!
Just to nitpick a bit, someone mentioned that the ft950 audio was designed for intelligibility and not fidelity. If you check out the -6db receive audio response on ssb and am you will see it designed for neither. Think lifeless, mind numbingly narrow.
 
RE: SDR: Ham Radio of the Future?  
by W7LV on May 23, 2008 Mail this to a friend!
It only took 55 years to go from U.S. Patent 1,103,503 (Robert Goddard's adaptation of the LaVal nozzle) to landing at Tranquility base...mostly with slide rules. And Goddard and von Braun's lifespans and working careers overlapped.
 
SDR: Ham Radio of the Future?  
by K0RGR on May 23, 2008 Mail this to a friend!
Yeah, in many ways, I don't think they've built the equal of the Collins 75A-4 yet. But in a contest, there are a lot of other rigs I'd prefer to use. Sherwood rates the Drake R-4C right up there with the best of today, and I've used those, too - they are great radios.

But I've never seen anything like the Flex demo I saw here a couple years back. One of our locals is deeply involved with Flex development, and he gave our club a very nice demo, using the Flex SDR-1000 for moonbounce. Not only did he make an inaudible moonbounce signal sound like it was S9, he uncovered another much weaker one that you'd never have heard with an analog radio.

I think that serious weak-signal folks will flock to the SDR's. Those of us who are more casual users may not.

Indeed, the closest receiver audio I've ever heard to the old Collins was a Yaesu FT-902DM I owned many years ago. It just had that same warm sound to it. It's resemblance to a KWM-2 was probably not an accident. But the receiver was much less selective than the older Collins - due to some poor design issues in the IF.
 
RE: SDR: Ham Radio of the Future?  
by W6RMK on May 23, 2008 Mail this to a friend!
KG6YV wrote: I guess we won't be launching an SDR to the moon for a while. it took 400 years from Newton's work to Apollo.

Sooner than you think, if not already. There's an SDR orbiting Mars (Electra on MRO) that we built at JPL, and it's been reprogrammed in flight to filter out an inband interfering signal from a science instrument. Come Sunday, when Phoenix lands on the surface, it will be communicating through that SDR.


 
RE: SDR: Ham Radio of the Future?  
by K9TEN on May 23, 2008 Mail this to a friend!
I won't go into the science of "SDR" radios vs "Others" but if we make comments about things at least get the facts correct! I have a Flex 5000A and so far it is the Best "Audio to my ears" sounding radio I have ever used! Some of my rigs I have owned:
JRC JST-245 (Rare radio-Most Hams have never seen one much less owned one-Awesome Audio!),FT-1000D, FT-990,FT-980,FT-897D,FT-857D,FTR-101,FT102,TS-950,TS-940,TS-930,TS-480HX,IC-765,IC-761,IC-756ProII,IC-756Pro,IC-756,IC-751A,IC-706MKIIG,Ten Tec Pegasus, Omni 6 OPt 3, and many many more! I have 1ea cable between my Flex 5000A and the computer! Thats not allot, most modern Hams have a good computer in there shack for other things so most would not have to run out and buy a new one! And as far as not having knobs to turn, if the main thing we want is an excellent receiver to pull out weak signals, would you really care if the radio has a blue display,crome knobs,back-lite buttons or NO KNOBS at all! If that is the case , don't read the specs, just look at the pictures and buy the prettiest radio you see! I like it when there is a 20 over station next to me on the band and I still can copy the week ones and the QRM does not bother me! Remember when some folks bought the Mustange LX with the same engine and suspention as the GT so they could get the performance but not have to pay the High Insurance cost for the "GT" model. Did not look as kool but would do the job! Buy what you want but don't forget that 90% of why you buy a HF rig is what in can hear and how it sounds on the air, not if it is pretty! Also put most of your money into your coax, tower and antenna system, you will come out better!
 
SDR: Ham Radio of the Future?  
by VE3ES on May 23, 2008 Mail this to a friend!
"but sdr has no sole, no mystery, no romance"

Amen to that brother!

Perhaps when Dell or Apple start making ham radio gear I'll get interested in SDR but until then give me the latest and greatest from Ten Tec or Yaesu or better yet, my old Drake C-line.
 
RE: SDR: Ham Radio of the Future?  
by WA2JJH on May 23, 2008 Mail this to a friend!
SDR is the future, I accept that.

Very true that the amount of SDR used in which stages affects performance and shear looks to some.

Radio's that have digital front ends have been around for a few years.

They can be found in some cell phones to military comm. gear.

I can only imagine that cheap PCIeX16 rev 2.0 cards have the bandwith and pleathea of UHF frequency clocks to choose for many SDR apps

I guess a good solution would be to have the next flex radio that takes advantage of the newer Quad core pentiums and it's 3.6 gig+ clock speed.

Keep the PC box on the floor. Problem is hams are more used to tweaking knobs than sliding controls on a virtual rig face plate.

I give it 5 years for True antenna port to audio stage to be all SDR.
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 23, 2008 Mail this to a friend!
WA2JJH Wrote:
"I give it 5 years for True antenna port to audio stage to be all SDR."

Well...just take a look at fully digital SDR's :

PERSSEUS SDR,
http://www.microtelecom.it/perseus/

QS1R SDR,
http://209.85.173.104/search?q=cache:UG6V8jmpp2cJ:www.philcovington.com/QuickSilver/+QS1R&hl=en&ct=clnk&cd=3&gl=u

SDR-IP,
http://www.rfspace.com/SDR-IP.html
PERSEUS SDR,QS1R SDR and SDR-IP have 104db !!!close in IMD with 500hz filter...again,Elecraft K3 with only 95db, so far behind!!!

Too much "hot air" abt ELECRAFT K3!!! K3 is not so good,like some People are thinking!!!


73!
John/SP2GGZ,N2KFC/YB1AQV
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 23, 2008 Mail this to a friend!
PERSEUS SDR,fully digital SDR...

Take a look at independent testing done by Leif,SM5BSZ:

http://www.nitehawk.com/sm5bsz/perseus/perseus.htm


PERSEUS has 104dB!!! IMD dynamic range with 2kHz separation with 500Hz filter!!! Elecraft K3 does not came even close ,with only 95dB !!!

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by G3RZP on May 24, 2008 Mail this to a friend!
Firstly, SDR means all things to all men - which adds to the confusion. As far as rx performance is concerned, the classic way of measuring IMD and so on isn't particularly good for receivers with wide band front ends. The same applies with SDR as well - the real instantaneous dynamic range (both phase noise and intermodulation limited) needs to be much higher if there's no RF filtering before the first conversion - whether or not that's an ADC or a down converting/sampling mixer. There's also the problem that a lot of SDR implementations have an intercept point dependent upon the level of the incoming signal - there's good article on this in RadCom magazine for January this year. This throws interesting problems professionally for doing frequency sharing studies, but that's another matter....
 
SDR: Ham Radio of the Future?  
by KE7TMA on May 24, 2008 Mail this to a friend!
I find it interesting that nobody has mentioned the only truly open SDR on the market, the GNU software radio. You can build your own interface or use the Ettus Universal Software Radio Peripheral. I haven't bought one yet, but plan to soon. The entire radio signal is generated in software from the ground up in source code.

Neat stuff.
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 24, 2008 Mail this to a friend!
Personally I prefer LINRAD by SM5BSZ and WINRAD by I2PHD...

LINRAD is the best...superior Noise Blanker and very good fully digital AGC system !!!
LINRAD is more like a SDR Design Studio,you can control full range of software parameters,take some time to learn but it is worthy...

WINRAD by I2PHD is too very good and is getting better...good program to start SDR Experimentation,easy to use...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by N8VB on May 24, 2008 Mail this to a friend!
"I find it interesting that nobody has mentioned the only truly open SDR on the market, the GNU software radio. You can build your own interface or use the Ettus Universal Software Radio Peripheral. I haven't bought one yet, but plan to soon. The entire radio signal is generated in software from the ground up in source code."

Not the only one. QS1R (and soon the QS1T) is also open source with all source code (software/firmware/fpga code) available.

<http://www.srl-llc.com>

Phil N8VB
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 24, 2008 Mail this to a friend!
Yes...QS1R is a very interesting and promissing Project...I like modular concept,Digital Board and separate RF Preselector Board...Good candidate for IF system retrofit for older Radios like RACAL RA1772 and others...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by KD8K on May 24, 2008 Mail this to a friend!
> Elecraft K3 does not came even close ,with only 95dB

Just for the record, the K3's 2 Khz IMD Dynamic Range at 2 Khz as measured by the ARRL is 102db, and 101db with the 250 Hz Filter as measured by Rob Sherwood.


One number that rarely is mentioned when measuring SDR's is Blocking Dynamic Range. It tends to be much less when compared with radio's with roofing filters because of the limited dynamic range of current Analog to Digital converters. I am sure this will improve as time goes on, but I think this is currently an issue when using SDR's in strong RF environments, at least it was in my situation. My Flex was the only radio that I ever owned that overloaded 200 Khz away when my neighbor ham was online.

73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 24, 2008 Mail this to a friend!
Well...measured by Sherwood with 500Hz filter is only 95dB!!!Check his list!!!

You can not compare dynamic range with 250Hz filter to dynamic range with 500Hz filter !!!!!!

Maybe in your situation you need better preselector...LC or Crystal???

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by KD8K on May 24, 2008 Mail this to a friend!
> Maybe in your situation you need better >preselector...LC or Crystal???

To me, that's just the point, in strong RF Environments, the SDR's need something in front of them to protect them from overloading, whether it be a roofing filters or preselector. I prefer a SDR radio with a roofing filter just for that reason.


73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 24, 2008 Mail this to a friend!
John...how strong signal from your local Friend do you have???

In New York City I am living very close to 4U1UN ,abt 1.5 mile, the strongest signal in my location at -40 dBm ,tested with use of commercial spectrum analyzer and very accurate HP3586 Level Meter...I am using SDR without any problems on HF...

You can craft your SDR according to your particular situation,but for sure you do not need many narrow roofing filters like in ELECRAFT K3 !!!
For VHF operation I am using 144MHZ to abt 9MHz conversion and in difficult situation bank of 1 0r 2poles crystal filters + SDR...signals levels on VHF are much stronger then on HF...but I do not need any very narrow filters...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by G3RZP on May 24, 2008 Mail this to a friend!
If you assume a measurement uncertainty of +/-0.75dB in the power applied from each generator (not an unreasonable figure everything considered), you get an uncertainty in intercept point and thus dynamic range of over 2dB.

The close in dynamic range figures are interesting but not always very meaningful, and are frequently limited more by phase noise than linearity. In practice, any interferer that close is going to have enough crud, splatter and probably key clicks associated with it to make the rx parameters somewhat academic!
 
RE: SDR: Ham Radio of the Future?  
by AC7CW on May 24, 2008 Mail this to a friend!
"To me, that's just the point, in strong RF Environments, the SDR's need something in front of them to protect them from overloading, whether it be a roofing filters or preselector. I prefer a SDR radio with a roofing filter just for that reason. "

Ahaaaa... so my SB102 with an inbuilt SDR from the first IF may yet rule the airwaves... well maybe not in a contest but it should be a lot of fun :) And has tube audio to boot, and not butt ugly..... the ugly tradition seems to be continuing, the software that runs the Flex and the other stuff is.... you got it..
 
SDR: Ham Radio of the Future?  
by N9DG on May 24, 2008 Mail this to a friend!
W4VR: “Some hams with SDRs tell me it's a "work in progress." So, perhaps there is a future for these radios.”

And if the designers did their hardware design homework correctly and have not boxed themselves into a corner then the radio will never be ‘done’. They will just keep introducing new software to keep adding major new features and to add completely different and operating activity specific software and user interfaces. The number one way for a SDR designer to box them self into a corner is to approach the design process from the mindset of starting with just knobs and buttons and then deciding to stuff SDR into what is an otherwise traditional radio. If they approach it from the perspective of it being an SDR first and then adding the user interface options (including knobs and buttons) to meet the desires and needs of wide range of users then that radio will have captured the spirit of what SDR is really all about.


W4LGH: “I will have to argue this as I think the FT-2000 and the newer TenTecs are SDR, as much as the Flex1000 & 5000's. Anytime the radio is driven by software, it is a SDR. The difference being that the Flex is open source software, and uses an out-board computer to operate it, the FT-2000 has its own processor and the software, at this point is propriatary, but this it will become open source before it is all over.”

By most definitions that I’ve read for ‘SDR’ it is true that the FT-2000 and Ten Tecs would be considered SDR’s. But where the rubber meets the road is whether or not that the manufacturer is truly taking advantage of it. Ask you yourself if the firmware upgrades that you have received for the FT-2000 have made any *dramatic* changes to how you can use it? Can that radio ever be able of adding additional receivers by changing software alone? Can it be easily interfaced with CWSkimmer in such a way that it could then decode all the CW signals over 10’s of kHz, - A true SDR can do both of those easily.

Bottom line is you can not get a good sense of what SDR is truly capable of, or where the state of the art is really at today by looking at the radios from the ‘big 4’. All those implementations start from the ‘traditional radio with SDR technology in it’ vs. an ‘SDR first design’ which may include as an option a traditional radio user interface (a.k.a. knobs and buttons). By doing so they are forever and more fundamentally limited in the scope of their SDR capabilities
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 24, 2008 Mail this to a friend!
To AC7CW...yes,You can craft your SDR any way you like!!!But I think that SB102 front end is not to strong...get better something stronger,like RACAL,TELEFUNKEN or maybe R&S...RACAL Recevers have some very "sweet" provision,You can drive mixers in RX from outside source!!!low phase noise premixer or VXO!!!proper connectors are factory installed...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 24, 2008 Mail this to a friend!
N9DG Wrote:
"Bottom line is you can not get a good sense of what SDR is truly capable of, or where the state of the art is really at today by looking at the radios from the &#8216;big 4&#8217;. All those implementations start from the &#8216;traditional radio with SDR technology in it&#8217; vs. an &#8216;SDR first design&#8217; which may include as an option a traditional radio user interface (a.k.a. knobs and buttons). By doing so they are forever and more fundamentally limited in the scope of their SDR capabilities"

Yes my Friend...you are so right...You have to try SDR to get good sense of SDR !!!
One thing that is so shocking for first time SDR user is icredible in Channel dynamic range...DX-pileup sounds so clear !!!

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by KD8K on May 24, 2008 Mail this to a friend!
> John...how strong signal from your local Friend do you have???

He lives on the same street as me, so I am sure it is quite strong.

>You can craft your SDR according to your particular situation, but for sure you do not need many narrow roofing filters like in ELECRAFT K3

Why would I want to "craft my SDR" on a SDR design that overloads when Elecraft's design already work's quite well at preventing overload?. All I can speak from is my experience, and my Flex would overload and my K3 does not. To me that speaks volumes about Elecraft's design. And I did not NEED many narrow roofing filters to do this as the default 2.7 Khz five pole filter worked just fine in preventing the overload from occurring. (Acutally it does not occur even with the 13Khz filter) Once again, while SDR's have achieved very high IMD dynamic range, improvement is still needed in blocking dynamic range. Without that improvement, in my opinion, there is problems with them in strong RF Environments.

73,

John, KD8k
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 24, 2008 Mail this to a friend!
KD8K Wrote:
"He lives on the same street as me, so I am sure it is quite strong."

OK John...same street,but how far away???
If You will have oportunity,check signal level...
Flex 5000 is a good SDR, but is not the best...new one,are at least 10dB better,and have much better phase noise characteristic.

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by IT9JCB on May 24, 2008 Mail this to a friend!
" by WD0CT on May 23, 2008
Just to nitpick a bit, someone mentioned that the ft950 audio was designed for intelligibility and not fidelity. If you check out the -6db receive audio response on ssb and am you will see it designed for neither. Think lifeless, mind numbingly narrow."

That's true, in order to compensate some metallic flavor in its sound, the japanese engineers have added a low pass filter just before tha audio PA. Someone spent lot of time in measuring this rolloff and the results are available in FT-950's Yahoo forum. The cutting is at about 1KHz...but the final result is not too bad.

73s Claudio
 
RE: SDR: Ham Radio of the Future?  
by IT9JCB on May 24, 2008 Mail this to a friend!
"by WB2WIK on May 23, 2008
Claudio, I like your idea.
Of course if we really wanted the rig to be bullet proof and more user serviceable, we could use 6146s in the transmitter P.A ."

Fully agree....forgot it, of course much better transmit sound with tubes and less $$. I did not mentioned it because the article refers to receive only isuues.

73s Claudio
 
RE: SDR: Ham Radio of the Future?  
by IT9JCB on May 24, 2008 Mail this to a friend!
" by N2KFC on May 23, 2008

WA2JJH Wrote:
"I give it 5 years for True antenna port to audio stage to be all SDR."


Well...just take a look at fully digital SDR's :
PERSSEUS SDR,
http://www.microtelecom.it/perseus/ "


Agree with N2KFC and don't be surprised if the Perseus designer is friend of mine: Perseus is very close to the SDR I have in my mind, just add the pre-selector, the good audio DAC and the tube audio PA.

73s




 
RE: SDR: Ham Radio of the Future?  
by IT9JCB on May 24, 2008 Mail this to a friend!
"by KD8K on May 24, 2008
To me, that's just the point, in strong RF Environments, the SDR's need something in front of them to protect them from overloading, whether it be a roofing filters or preselector"

Agree.....
As mentiond before I think that pre-selector is mandatory in a fully digital SDR, so the signal chain should be "presel-->high IP3 preamp-->ADC".
But this is related to the current state of art of fast ADCs; in a not too far future, DVD-type 24 bits ADCs as those used in our IC-756proIII or FT-2000 at low IF as 30 KHz, will be available at faster speed, allowing to be eventually fed directly with the antenna signal passed trough a simple low pass filter.

73s
 
RE: SDR: Ham Radio of the Futureand back too  
by WA2JJH on May 24, 2008 Mail this to a friend!
Why (WIK) Steve, (LGH) ALAN and (JJH) myself rave on about the TR-7 is for many valid reasons.

The pre-amp less design makes for an ultra quiet radio with sensitivity on par with any rig today. Do not let the .5uv spec fool you. It will get any signal any $10,000 rig can with an .18uv rating. The RX is almost overload proof.

(User repairable, no menu's, and an ultra narrow 1st IF filter. Mil spec like construction. Modular design. The Drake TR-7 was the $10,000 rig of today. A TR-7/A with all the options (filters,NB,GC) checked in at about $1500-$2000 in 1978.

The filter (1st IF) is so narrow, that FM and ESSB is impossible. The 2nd IF is 2.3kc. 4KC for AM is used.
A low distortion audio IC drives a 3 ohm oversized speaker.
The sound of a dead quiet, overload proof (almost), and low DX signals that pop out of the very soft hiss is something that should be a "GOLD STANDARD" NUFF SAID!

Result is an RX that gets its signal with no DSP, SDR, or menus.

The radio was made in 1977!

If a company can make an SDR rig that will emulate a TR-7 in RX performance in any RFI environment, I would buy it in a NYC second.

Be nice if it used the user replaceable circuit boards. Be nice if the rig could be in a stand alone box. Hook it up to the PC for SDR algorithms upgrades only. A nice portable box. A price under 2K would be nice too.
If one wanted, they could have an upgrade that forces you to have your PC hooked up.
This upgrade would only be for those that want the video game flight emulator rig experience. HI-HI.

W90Ys points were very good. I would not mind having the ability to custom design the virtual face plate.
I could design my own face plate or select from the classics. Have as many or few knobs as I wanted to on my PC screen.
I am sure the same JOG/SHUTTLE external USB peripheral, I use on ADOBE PREMIER, would make an excellent multiple VFO knob.

The ability to RX several antennas/bands and having a QSO at the same time is ultra nice!
The ability to make the rig work like an F-22 HUD is cool too. I would rather use my projection TV with 5.1 Dolby sound.

This video game like feature would attract youth as well. I guess with a flex-5000 you could simulate bad band conditions too, no? Did the flex people think of making old classic rig emulations modes?
I have not used a FLEX-5000 yet. I am sure I would spend months trying everything. Settle down on a few pre-sets, then try out A/B operating comparisons with my old TS-950SDX. An early DSP, but not SDR radio. There are plenty of ASIC chips and CPU controlled/optimized stages. However FIRMWARE means just that! The firmware is very good. However, I like to push envelopes.

I fully understand why the Flex-5000 is not stand alone. A lot of algorithm’s to run real fast. If the Flex people had a stand alone option, they could sell to many hams that still like the box and knob rig of today.

Perhaps a 3erd party can make a small black box PC that just needs a 4 gig SD chip for the latest SDR updates. OHHHH…that would leave the flex people open to the Chinese reverse engineering it.

DO NOT LAUGH!. China did not want to invest the billions in guidance systems for their ICBMS. What did they do!!!! THEY TOOK A CONSUMER GARLIN GPS and modified it to guide their missiles. When your dealing with 2 megatons, a few hundred meters is moot!!!!!!

Just give me the ability to disconnect the rig from a PC after I am finishing fun mode. After the PC disconnect, I would be happy if an on board ASIC would
Leave me with a nice stand alone box with real knobs.

Hmmm, anybody see a few cottage industries? I do.
One example. A 3erd party can make custom STAND ALONE face plate/rig enclosures. Imagine having a stand alone SDR rig with a Collins KWM-1 or DRAKE TR-7 face plate!!!!!


 
SDR: Ham Radio of the Future? It will take time.  
by AI2IA on May 24, 2008 Mail this to a friend!
SDR has a very long way to go before it gets general acceptance and frequent use.

The two big issues are: SOFTWARE QUALITY ASSURANCE AND RELIABILITY.

Communications transceivers are complex devices. Moving them over as far as possible into SDR is a huge challenge.
 
RE: SDR: Ham Radio of the Future?  
by W9OY on May 24, 2008 Mail this to a friend!
Perhaps some did not entirely understand what I wrote. I routinely run 1500W SSB on 75 with my SDR-1000 and simultaneously rum 1500W on 20, 30 40 or 160 running in DX pileups with the F5K. My antennas are 100ft apart full size verticals. This is called a strong RF environment. I have measured +23 dbm of RF on the RX antenna while transmitting. There is no desense or any kind of hash in either radio. How the radio would perform for example on a DX pedition with one radio on SSB and one radio on CW on the same band in the same tent I'm not sure. It is probably not as bullet proof in that situation as the K3, but then you give up virtually all of the Software features like external pan adapters and point and shoot with the K3 in that situation as well. I'm interested in what I'm interested in at my station according to how I operate. I am not interested in cooking some lame brained far fetched situation that virtually never occurs and then choosing a radio based on that situation. If I decide to spend the dough to go to some atol in the Indian Ocean I'll chose what ever radio fits that bill, since the cost of the radio will be the least of the expense.

I remember with my SDR-1000 when the watch receiver feature was added, one day there was one receiver, then I downloaded some new software and the next day there were 2 receivers in my radio. The same is true of the AGC. The AGC wasn't the greatest in the early iteration of the radio and in one day, a new AGC algorithm was written and the radio now has arguably the best AGC in ham radio. This kind of flexibility is not available in any other radio with out actually breaking out the soldering iron. When I rebuilt the RX in my TS-820S it was a year long project of hundreds of hours of experimentation and design, it didn't happen in one day after rewriting a few lines of code. I did not rewrite the code, I simply downloaded the code and I had a new radio, as did thousands of other flexers. This is the point. To upgrade the radio takes minutes not tens or hundreds of hours, and the entire fleet of radios are able to be upgraded in minutes, nor does it take a trip back to the factory for some kind of retrofit. An example, the FT-1000 series of radios had built into it a design flaw that made it have a very clicky CW signal. That design flaw continued for something like 15 years. That would not happen with a radio like the F5K. That kind of flaw could be fixed in the entire manufacturing run of the radio over night no matter how many radios were out in the field.

One thing you have to remember is that the SDR-1000 was designed as a hobby radio. It was an engineering experiment by K5SDR to see what he could do with a few parts and some software. It was basically an electronic laboratory which is why it used a "sound card" etc to do the ADC DAC heavy lifting. The original radio was 3 circuit boards and the original software was I believe in visual basic. The radio has gone through and continues to go through astounding exponential changes. The TR-7 sits on the desk, the same radio it was 40 years ago. It is the rapid development and the iterative nature of the development that is part of the SDR fun. It is very interesting as just a ham with no connection to the manufacturer, to see an idea you may have implemented into the radio as development proceeds. Again no other radio offers this kind of experience. The closest I had to this was working with N4PY on implementing some ideas into his series of CAT programs for the TT radios.

I can't tell why Steve had trouble with his SDR-1000 that he tested. I do know he loves to bring it up at every chance he has. I also know he could probably get rid of any hash from his 1.5MW station by inserting a simple little trap into the RX line of a Flex 5K, like I used to do with some of the 1400khz broadcast station overload I had in my Drake R-4 on 160, but then its easier to curse the darkness than light a candle.

As far as reverse engineering goes, the software is GPL, in other words the Chinese can just down load the source code and read it for themselves. This is the great advantage of this radio and the reason for its spectacular development. Individuals are NOT at the mercy of what some designer thinks a radio should be. You are totally free to modify the radio's guts any way you like, as long as if you do make a change and publish the change you also make the source code available. You can not change a Ten Tec or a Yaesu or any other radio like this since the source is proprietary and owned by manufacturer. Also you are limited by the horsepower of the "processor" they stick in the radio. With something like the F5K if you want a 64 bit DSP you simply compile around a 64bit computer, a very different concept than any other radio on the market.

Another feature of the F5K that I haven't discussed is its I/O bus which is based on the phillips I2C spec. The I2C bus is a 3 wire master/master or master/slave serial bus that is bidirectional, and the possible things you can hang in this bus besides the usual switches and relays include eproms, potentiometers, and various controllers. This allows the F5K to act as a total station control center and allow you to write code that can control very complex situations such as an EME station including rotor controls (remember the programmable potentiometer), or the possibility for various servo mechanisms like auto tune amps that are linked to 5K for control. In other words you could build a rack of auto tune custom amps that would follow your F5K perfectly. once again there is no other radio that offers such flexibility and possibility for station integration. Sure you can think up situations where the F5K will fail. For every one of those you tihnk up I can think up 2 dozen instances where your radio would never even get off the ground. For example I could remote my F5K 100 miles from the 1.5MW shortwave station on 20 acres of 4 squares and beams and beverages using off the shelf technology. Or you can set it up to run cross platform. I have my F5K running off a windows machine in my ham shack and I can control it from the Linux box in my office. If I want I can take my laptop to the Starbucks and work DX while sipping my Latte.

Try doing that with a TR-7.

Best I can tell you, if you don't want an SDR, don't buy one, but don't make up a lot of baloney justifications why the radio isn't up to snuff.

Lemme see: Here's why I won't buy an SDR. You can't take the radio into the Voice of America Transmitter plant cafeteria and work field day using a Buddipole indoors!!! Therefore the radio is no good.

73 W9OY
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 24, 2008 Mail this to a friend!
W90Y Wrote:
"Best I can tell you, if you don't want an SDR, don't buy one, but don't make up a lot of baloney justifications why the radio isn't up to snuff.

Lemme see: Here's why I won't buy an SDR. You can't take the radio into the Voice of America Transmitter plant cafeteria and work field day using a Buddipole indoors!!! Therefore the radio is no good. "

Hello Lee...yes,I agree with you...and when you ask People who are saying that SDR is no good,what is interfering signal strenght??? well...no answer!!!

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: is common in cell and mil radios  
by WA2JJH on May 24, 2008 Mail this to a friend!
<<<<SDR has a long way to go……..
Acceptance and frequent use. >>>>>

The transistor had the same problems in the 1950's.
Tubes were considered the defacto standard.

The rest is history.
<<<SDR has a very long way to go before it gets general
Sometimes it is a budget and consumer demand issue.

Total SDR from Antenna port to final D/A at the speaker driver are common in military HF man packs.
The Harris Falcon series is one example ( 1.6-60 MHz 20W HF transceiver. SDR/DSP from RF port to handset.) Problem is......If you have to ask how much the radio costs, you simply cannot afford it. :)

Some Cell phones are all a few chips with proprietary
Software and ASIC/RICS CPU's. Since they are manufactured in mass quantities, cost is way down.

A good freebie pub. For the latest in SDR and all state of the art RF in general is..."Microwaves and RF".
It is chock full of the latest chip sets for SDR in cell phones and commercial/mil transceivers.
Ultra wide band A/D's to Digital I and Q front ends and demods are explained.

WWW. Microwaves and RF.com. To get this monthly mag free, a little creative writing is needed.

Fill out the application on line. Stating your occupation as a Ham radio operator will NOT get you on Penton press industry professional list.

Developer kits sell for $100-$200.


 
RE: SDR:  
by WA2JJH on May 24, 2008 Mail this to a friend!
<<<<< If I want I can take my laptop to the Starbucks and work DX while sipping my Latte.>>>>>>>

Sounds Great to me! Thats living good!
Great way to expose the general public to Ham Radio.

Can I ask what the total expense was for your HF station from a laptop cost you?

Be nice to do it from the new I-phones comming out in a few months. The only legal glitch, might be that cell phones are encrypted. The FCC forbids scrambled
tansmission

My dream was always an HF shack being used from a dual bander H-t and a laptop miles away in a public park.

73 DE MIKE WA2JJH.

 
RE: SDR:  
by N2KFC on May 24, 2008 Mail this to a friend!
LINRAD SDR...

"LINRAD SDR with High -Performance Hardware"by SM5BSZ

http://www.nitehawk.com/sm5bsz/linuxdsp/qex/040102qex020.pdf

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by WA2JJH on May 25, 2008 Mail this to a friend!
I knew FFT's(fast fourier transforms) were going to be involved. The prototype used a mere Pentium 3 at 800MHZ clock.

The good news is that the new dual and quad cores are not only a large jump in clock freq.

Q6600 2.4 ghz overclocks to 3.6ghz with water cooling.
Thats a 4 core pentium that sells for $200.

The top end is The newer 45 micron die QX-9000 series.

Quad core. (actually they are 2 dual core chips with a common Fsb.

DDR-2 1.15 gig memory is dirt cheap 2 gigs for $100.

The other reason to go goompers for the microwave clock freqs is the fact that one can build more RF-HF circuitry inside the computer.

The days of computer generated artifacts will be of little concern.

If you go for Quad core extreme.....wait!!!!!
I went for Intels most powerfull quadro-pentium. The QX-9650. It is a 3 gig chip that overclocks to 4gig using just the standard fan and heatsink.

Windows XP 32bit crashes at 3.8 gig. Do not buy Vista just yet. XP is still faster than Vista in 32 bit mode.

The Quad core pents range from $200-$1200. The $1200 is the new Pentium Extreme quad that clocks at 3.2 gig with just a heast sink and fan. The QX-9750.

Save your money. I purchased the 3.O gig QX-9650 for $1000.

Money well wasted!!!!

The bottom end chips the 2.4 gig Q6600 easily overclocks to 3.6 gig with water cooling.

My point is, if you are in the market for a powerfull PC for SDR, check your specs!!!!!

Since these SDR radio's are plug in cards, make sure you get the newer motherboards.

I am writting an Eham artical now explaining all the new chips, mobos, and the new hoopla on plug in card formats.

The short story is that the higher clocks, improved PWMs, and 85% efficient switcher supplies is all good news for building more of the transciever inside the desktop PC.

 
RE: SDR: Ham Radio of the Future?  
by AI4NS on May 25, 2008 Mail this to a friend!
W9JCM says:
"Yes "Sherwood" had it out for Flex Radio thats nothing new. And man they are having some issues with that K3. "


And what issues is Elecraft having with the K3, aside from minor tweaks, and demand far exceeding supply?

I have not seen any show stoppers on the K3 yet, so what did you mean?

Mike
AI4NS
 
RE: SDR: Good QST artical.  
by K9COX on May 25, 2008 Mail this to a friend!
There is no difference in the performance metrics of a SoftRock, SDR-1000, and SDR-5000 when run on a 1.6 gHz single core or 3.6 gHz multi-core wizbang special. I'm not saying that the radios aren't different but that each radio performs the same once you reach a point of diminishing returns as far as computer speed. More is not necessarily better. Differences noted are with additional processes taking place.
 
RE: SDR: Good QST artical.  
by KD8K on May 25, 2008 Mail this to a friend!
> you give up virtually all of the Software features like external pan adapters and point and shoot with the K3 in that situation as well.

Actually, this is not correct. The K3 has an IF output which can be fed into a device such as N8LP's LP-Pan adapter or Soft Rock with buffer amplifier and can be used with WU2X's modified version of PowerSDR. See http://www.wu2x.com/sdr.html and http://www.telepostinc.com. This gives full point and click tuning using PowerSDR with the K3! I click on the signal in PowerSDR and it sets the K3 to that frequency! I have been using this method for a month or so and It works quite well. I also get most of the other features of PowerSDR, like dual receive, etc. To me, this is the approach I like the best. I am not limited to computer control only, but at the same time I also get most of the features of PowerSDR.

73,

John, KD8K
 
RE: SDR: Good QST artical.  
by KD8K on May 25, 2008 Mail this to a friend!
> People who are saying that SDR is no good,what is interfering signal strenght??? well...no answer!!!

I wish I could give you an exact signal strength, but all I can say is that the signal is above 60db over 9, yes, a very strong signal. However the SDR-1000 I was using has a blocking dynamic range of 111db according to the ARRL review. The K3 has a BDR of 139 as per the ARRL. For me, this made a difference. With the Flex,I could not operate on 40m CW when he was using SSB in the upper part of the band. With the K3 I can. In the end, It's the results that I care about. I have nothing against SDR, it has many great and interesting features and great flexibility and I am sure it will only improve as faster and better Analog to Digital converters and processors come out. Right now, for me at least, a Hybrid approach such as what the K3 offers is what has worked best for me.

73,

John, KD8K
 
RE: SDR: Good QST artical.  
by N2KFC on May 25, 2008 Mail this to a friend!
KD8K Wrote:
"I wish I could give you an exact signal strength, but all I can say is that the signal is above 60db over 9, yes, a very strong signal. However the SDR-1000 I was using has a blocking dynamic range of 111db according to the ARRL review. The K3 has a BDR of 139 as per the ARRL. For me, this made a difference. With the Flex,I could not operate on 40m CW when he was using SSB in the upper part of the band. With the K3 I can. In the end, It's the results that I care about. I have nothing against SDR, it has many great and interesting features and great flexibility and I am sure it will only improve as faster and better Analog to Digital converters and processors come out. Right now, for me at least, a Hybrid approach such as what the K3 offers is what has worked best for me"

Hello John...thank You for info...

So...S9+60db, this is abt -113dBm at ant connector and abt +117dB above -130dB MDS...Yes,this is too much for old SDR-1000,You need abt 6dB ATTN in ANT line,but most of the time You do not need -130dB MDS level on HF Bands,most of the time You can use 10dB or more on HF,specially lower Bands,this depends on level of Band noise at particular time...
SDR-1000 is the old design...FLEX 5000 and many others modern SDR's will handle +117dB above 130dB MDS very easy!!!
ELECRAFT K3 is not so good like You are thinking...take a look at Sherwood Table,140dB BDR but phase noise limited!!!at 100kHz separation!!!much worst at smaller separation...ELECRAFT K3 has serious phase noise problem!!!
ELECRAFT K3 Two Tone IMD at 2kHz separation with 500Hz filter is 95dB PHASE NOISE LIMITED!!!
HAM RADIO OPERATORS are smart People and we know difference abt testing IMD with different filters!!!
Testing ELECRAFT K3 with 200Hz IF filter and compare results too other Radios with 500Hz IF filters is WRONG and is UNETHICAL!!!
For over 30yrs Rob Sherwood is publishing test data in his list according too 2kHz separation with 500Hz IF filter...current listing is:

1-ELECRAFT K3 with phase noise limited 95dB with 500Hz filter
2-FLEX 5000 with 96dB with 500Hz filter
3-Ten-Tec ORION II with 95dB with 500Hz filter

Well...so why Flex5000 with 96dB is in second place???I am sure that number 96 is bigger than number 95,I am sure that You agree with me???

Now lets make our list for the best RX using Rob "listing standart" 2khz separation with 500Hz IF filter:

1-QS1R and PERSEUS and SDR-IP 104dB with 500Hz filter
2-FLEX5000 96dB with 500Hz filter
3-Ten-Tec ORION II 95db with 500Hz-no noise limitation
4-ELECRAFT K3 95dB phase noise limited with 500Hz

Well...in The Real World,if we are putting all "bias" away...FULLY DIGITAL SDR's are clear winners!!!

Ham Radio is the technical Hobby...we do not sell apples and oranges or Sneak Oil!!!
FLEX5000 with 96db deserves better place on Sherwood list!!!

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by N2KFC on May 25, 2008 Mail this to a friend!
Correction S9+60db is abt -13dbm...type error...

73!
John/n2kfc
 
RE: SDR: Good QST artical.  
by N2KFC on May 26, 2008 Mail this to a friend!
Claudio IT9JCB Wrote:
"The radio engineers have to spend lot of their time investigating on why an old 60s receiver sounds so good and probably they will find the right answer, but not NOW: SDR is still too young. "

Hello Claudio,how are You today?

Well...You asking why your old TELEFUNKEN from 50's sounds so good???
TLEFUNKEN has a very long history in Radiocommunication Industry and was producing same of the best Radios,like faumous TELEFUNKEN E52B for German LUFTWAFFE,the best Radiocommunication RX of WWII
to TELEFUNKEN E1800 one of the best analog Radios ever made!!!
Old Radios sounds so good,specially on CW,bcs they are useing very low phase noise LC OSC...so they sound crisp and clean...no mushy and noisy like phase noise limited ELECRAFT K3 !!!

73!
John/sp2ggz/n2kfc/yb1aqv

 
RE: SDR: Good QST artical.  
by N2KFC on May 26, 2008 Mail this to a friend!
Claudio,take a look at TELEFUNKEN E1700...

http://209.85.129.104/search?q=cache:KGnLy5393koJ:www.kurzwellen-freak.de/HomepageClassic01/e1700.htm+www.kurzwellen-freak.de&hl=en&ct=clnk&cd=2&gl=us

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by KD8K on May 26, 2008 Mail this to a friend!
Hi John,

>ELECRAFT K3 is not so good like You are thinking...

You made some interesting comments with regard to that, here is my thoughts below:

>testing ELECRAFT K3 with 200Hz IF filter and compare results too other Radios with 500Hz IF filters is WRONG and is UNETHICAL!!! >

Actually what I want to know is what the RADIO is capable of. I see nothing unethical about posting results based on what a radio as a whole is capable of. If a radio is capable of a 101db IMD DR, then that's what I want to know, regardless of filter sizes. However, I think we are splitting hairs here as the difference between 101db and 96db is probably not noticeable in the real world.


>take a look at Sherwood Table,140dB BDR but phase noise limited!!!at 100kHz separation!!!much worst at smaller separation...ELECRAFT K3 has serious phase noise problem!!!


So a radio that is Phase noise limited at 140db is worse then a radio that is not phase noise limited at 123db? I am not sure I agree with that. The K3 was not phase noise limited during the test at 123db,124db, 125db, etc, and it is worse then a radio that have a BDR or 123db? How do you know that the 123db radio would not have also been Phase Noise Limited if it was capable of a 140db BDR? It was not capable of that, so we do not know the answer to that question. I also take note that the ARRL review did not show any Phase Noise Limited Results, so I highly doubt any claim that there are any serious phase noise issues, especially when the the K3 has one of the best LO Numbers on Rob's chart.

Plese understand that my comments with regard to BDR on SDR's is meant in a constructive way. SDR has many valuable and great features, and I enjoyed my SDR-1000 when I had it.I just think that BDR is a important issue that needs to also be taken into account. It is important to some of us! It was rather frustrating to be unable to use the Flex when I could other radios.I am glad to see the improvement in BDR on the Flex 5000 and I hope that further improvement does continue.

73,

John, KD8K




 
RE: SDR: Good QST artical.  
by WA2JJH on May 26, 2008 Mail this to a friend!
<<<<There is no difference in the performance metrics of a SoftRock, SDR-1000, and SDR-5000 when run on a 1.6 gHz single core or 3.6 gHz multi-core wizbang special. I'm not saying that the radios aren't different but that each radio performs the same once you reach a point of diminishing returns as far as computer speed. More is not necessarily>>>>>

All that means is that the software is not written for multicore procs. A darn shame.

 
RE: SDR: Good QST artical.  
by N2KFC on May 26, 2008 Mail this to a friend!
Hi John,

You said:"Actually what I want to know is what the RADIO is capable of. I see nothing unethical about posting results based on what a radio as a whole is capable of. If a radio is capable of a 101db IMD DR, then that's what I want to know, regardless of filter sizes. However, I think we are splitting hairs here as the difference between 101db and 96db is probably not noticeable in the real world. "

Well..the radio with 100dB IMD DR with 500Hz will have 127dB IMD DR with 1Hz filter !!!If You compare dynamic range of radios YOU HAVE TO SPECIFY filter bandwidth...otherwise it is nonsense...

You said:"So a radio that is Phase noise limited at 140db is worse then a radio that is not phase noise limited at 123db? I am not sure I agree with that. The K3 was not phase noise limited during the test at 123db,124db, 125db, etc, and it is worse then a radio that have a BDR or 123db? How do you know that the 123db radio would not have also been Phase Noise Limited if it was capable of a 140db BDR? It was not capable of that, so we do not know the answer to that question. I also take note that the ARRL review did not show any Phase Noise Limited Results, so I highly doubt any claim that there are any serious phase noise issues, especially when the the K3 has one of the best LO Numbers on Rob's chart"

Well...Rob is giving phase noise value at 10kHz separation from signal,You have to take look at wide band phase noise characteristic...I know phase noise characteristic for ELECRAFT K3 and Ten-Tec ORION II...ORION is better abt 10db at 2kHz!!!huge difference!!!specially for CW operators,ORION is much better for CW then ELECRAFT K3,I did A-B test myself!!!

Take a look at other radios with abt 140dB BDR on rob's list:RACAL,DRAKE TR7,Ten-Tec...ELECRAFT K3 is the only Radio phase noise limited!!!We are talking abt 100kHz separation!!!at this separation something is wrong with ELECRAFT K3!!!

This is not a matter what is better 140dBBDR or 125dBBDR...but what do you need???125dB is a lot,most Ham operators will never need more on HF...VHF this is different story...

IF you know phase noise characteristic you can estimate BDR for any front end...

I prefer Rob's data...ARRL testing metods are not Professional...
For over 30Yrs Rob's was very "solid" ,but now some funny things are going abt ELECRAFT Products...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by KD8K on May 26, 2008 Mail this to a friend!
Hi John,

This is an interesting discussing to me, here is my thoughts:

>prefer Rob's data...

Yes, Rob indeed has a very good reputation. So does the ARRL. We have conflicting data here, so it becomes a matter of which data you want to believe. Whichever data you prefer is your choice, but I still say that if there was a SERIOUS (your description) problem with Phase Noise on the K3, it would have shown up in the ARRL's data.


>IF you know phase noise characteristic you can estimate BDR for any front end...

If that is the case, then would not the Flex 5000, Orion and others have far more of a Phase Noise Problem because their BDR is worse? Perhaps I missing something on this one. Remember the K3 has a Blocking Gain Compression of 139db AT 2 KHZ according to the ARRL.


>You have to take look at wide band phase noise characteristic..

>Rob is giving phase noise value at 10kHz separation from signal

>know phase noise characteristic for ELECRAFT K3 and Ten-Tec ORION II...ORION is better abt 10db at 2kHz!!


Once again, perhaps I am missing something, but it appears as if you are saying you are saying that you have to look at the wide band phase characteristics, but then say the Orion is better because it's Phase noise numbers is better close in. I am not saying the Orion is or is not better, but my understanding is that you do have to look at wideband characteristics, and from Rob's and the ARRL's data it looks good to me, certainly nothing to Indicate a SERIOUS Phase noise problem. I do not however claim to be an expert on this subject.


>take a look at other radios with abt 140dB BDR on rob's list:RACAL,DRAKE TR7,Ten-Tec...ELECRAFT K3 is the only Radio phase noise limited!

That is a good point, perhaps the TR7, or Omni VI+ may be slightly better close in Phase Noise wise, that does not mean the K3 has a SERIOUS Phase noise problem. And once again, is it not the Wide Band Characteristics that is the important thing?


>this is not a matter what is better 140dBBDR or 125dBBDR...but what do you need???125dB is a lot,most Ham operators will never need more on HF..

Agreed. I am not sure if 125db is enough for me with another ham living so close by, but it may be enough for others. But, Again my point is that a 140db Phase limited result is not worse then a 125db non phase limited result.


>If You compare dynamic range of radios YOU HAVE TO SPECIFY filter bandwidth...otherwise it is nonsense...

In looking at Rob's data, I am not sure he specified what filter size he used when measuring the Flex 5000, At least I could not find it. Perhaps he should have. But in any case, the SDR's tend to have the same IMD DR regardless of filter size, so I believe it is safe to assume that a 96db IMD would result when using a 200hz filter. This would still put the K3 ahead of the Flex.Also, the footnote states that he measured the Orion at 96db using the 300Hz Filter. Again, this is splitting hairs as the difference is so small as not to matter.


>ORION is much better for CW then ELECRAFT K3,I did A-B test myself!

I wish I had a Orion to A/B with! :) Which one is better or worse can be a personal view, but I have A/B the K3 with a number of radios, including the Flex, and in my opinion, the K3 has the quietest and cleanest sounding receiver I have heard. Outstanding CW radio, especially with the latest firmware! Excellent QSK, razor sharp filters. Nothing against the Orion, I am sure it is outstanding also!




73,

John, KD8K
 
RE: SDR: Good QST artical.  
by N2KFC on May 26, 2008 Mail this to a friend!
Hello John,

You said:"In looking at Rob's data, I am not sure he specified what filter size he used when measuring the Flex 5000, At least I could not find it. Perhaps he should have. But in any case, the SDR's tend to have the same IMD DR regardless of filter size, so I believe it is safe to assume that a 96db IMD would result when using a 200hz filter. This would still put the K3 ahead of the Flex.Also, the footnote states that he measured the Orion at 96db using the 300Hz Filter. Again, this is splitting hairs as the difference is so small as not to matter. "

Well...ORION has 95dB with 500Hz filter at 2kHz separation,and take a look at Rob's "i" note:"i At 1 kHz dynamic also 95 dB but with 300 Hz roofing filter enabled "...ORION has 95db with 300Hz filter at 1kHz SEPARATION TOO !!!ORION has the best synthesizer at close separation !!!
At 1kHz separation ELECRAFT K3 Will have less than 90db phase noise limited !!!and if we go to 500Hz separation even worst!!!
This is why very low close in is so important for CW operators!!!
Modern SDR's are useing ultra low noise XO's,and have superior close in and in the band IMD DR!!!
A few of my Friends,former military/commercial CW operators,after trying SDR for the first time ,said,that this is the best CW Radio they were ever useing!!!

I do not want to comment on ARRL test data...like I said I do not trust them...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by KD8K on May 26, 2008 Mail this to a friend!
Hi John,

Apparently our discussion has changed from the K3 having a serious phase noise problem to which has the best phase noise characteristics, the Orion or the K3. :) I think they are both pretty good radio's!


You said "Well...ORION has 95dB with 500Hz filter at 2kHz separation,and take a look at Rob's "i" note:"i At 1 kHz dynamic also 95 dB but with 300 Hz roofing filter enabled "...ORION has 95db with 300Hz filter at 1kHz SEPARATION TOO !!!ORION has the best synthesizer at close separation !!!"

I noticed this on Rob's web site under "Receiver Performance" I quote: "The anomaly in the phase noise world presently is the Orion. It has very good close-in phase noise, but it degrades significantly at 50 to 60 kHz." and "So in reality, the Orion did not have the quietest synthesizer ever tested, it was just different. It’s maximum noise occurred at wide spacing, not close-in spacing."

So yes, According to Rob, the Orion does have very good synthesizer noise characteristics at closer separation, but, is not the quietest synthesizer ever tested. Which is better for SSB, CW, I am not sure, they are both great rigs! The Orion's Phase noise may not be better, just different, especially when you consider the Orion's poorer phase noise at wider bandwidths. And from what I understand, it is the total wide band characteristics of the Phase Noise that is the important thing.


You said "I do not want to comment on ARRL test data...like I said I do not trust them.."

Understood, I guess we will have to agree to disagree on that :)

It's been an interesting discussion my friend, I will let you have the last word on the matter!

Hope to work you on CW sometime!

73,

John, KD8K

 
RE: SDR: Good QST artical.  
by N2KFC on May 26, 2008 Mail this to a friend!
Hi John,
You said:"I noticed this on Rob's web site under "Receiver Performance" I quote: "The anomaly in the phase noise world presently is the Orion. It has very good close-in phase noise, but it degrades significantly at 50 to 60 kHz." and "So in reality, the Orion did not have the quietest synthesizer ever tested, it was just different. It&#8217;s maximum noise occurred at wide spacing, not close-in spacing."

This is not the anomaly...this is design choice of PLL crrosover point!!!Ten-Tec design, so far is superior at close separation and good enough at wider separation-this is the ART of engineering to design "just right"...Ten-Tec designers know very well what they are doing !!!
We need the best close in and in the cannel IMD DR and good enough at wider separation...Strong signal problems of Multi operators multi-multi KW TX's are not our problems !!!

I am operating from different places in The World...in USA HF bands are very quiet...we have some problems in Europe on 40mtrs and in Indonesia on 21MHz-some very strong USA Navy Digital transmissions...

Thank You for a talk...and I just hope,that You and other ELECRAFT K3 user,after excitement of "new Love" will go down,will take a new quiet,cold look at K3...live is brutal and objects of perfect uncondisional love are not so perfect in the end...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by KD8K on May 27, 2008 Mail this to a friend!
Hi Johm

Sorry, Just could not resist answering a few things (and then you can have the las t words!) :)

You said "This is not the anomaly...this is design choice of PLL crrosover point!!!Ten-Tec design"

Remember, calling it a anomaly is not what I said, that is what Rob was quoted as saying on his web site!


You also said earlier "You have to take look at wide band phase noise characteristic"

I agree with that, but you want to ignore your own words with regard to the Orion. According to Rob, it's wide band characteristics are not as good as it's close-in.



"take a new quiet,cold look at K3"

That my friend, is what I have done! I have looked at all of the facts! including the ones from the ARRL that I can not just ignore!

73,

John, KD8K
 
RE: SDR: Good QST artical.  
by N2KFC on May 27, 2008 Mail this to a friend!
Hello John,

How are You?

yes...I know that Rob said this...

You said:"You also said earlier "You have to take look at wide band phase noise characteristic"

I agree with that, but you want to ignore your own words with regard to the Orion. According to Rob, it's wide band characteristics are not as good as it's close-in. "
John,not like that...yes,you have to take look at wide band phase noise caharacteristic and after that you make decision based on your criterias...but my criterias can be different then yours I think that you agree with me???
I am testing and building Receivers for over 40Yrs,and I have commercial test equipment and I know exactly what I need...

Like I said, ARRL test methods are not Professional...I am useing standart idustry methods,like described by Urlich Rhode N1UL...

My opinion is,that at this time if you are looking for new RX you have two choices: SDR or Ten-Tec...but you can have different idea and this is just fine!!!

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by KD8K on May 27, 2008 Mail this to a friend!
Hi John,

>but my criterias can be different then yours I think that you agree with me???

>My opinion is,that at this time if you are looking for new RX you have two choices: SDR or Ten-Tec...but you can have different idea and this is just fine!!!

Yes, Absolutely. Finally some things we do agree upon! :)

It is interesting to look at various design techniques, and discuss their advantages and disadvantages.

I in no way view the K3 as a "Perfect Radio", No Radio Is. It has its flaws as all radios do. I also do not view it's synthesizer design as perfect, I just simply did not see it as seriouosly flawed, but as you said, maybe for your purposes (or others) it is. :) We have to look at what criteria is important for our situation. The Orion's design is outstanding, but it is a bit more expensive also. I wish I had one sitting beside my K3!

73 to you!

John, KD8K







 
RE: SDR: Good QST artical.  
by IT9JCB on May 27, 2008 Mail this to a friend!
" N2KFC wrote:
Old Radios sounds so good,specially on CW,bcs they are useing very low phase noise LC OSC "


Hi N2KFC,
I partly agree, the newest generation rigs use good DDS in their synth and a good DDS (when well designed) should be far superior to a free running VFO, especially close-in to the carrier. But I agree that poor designed DDS can have high phase noise, as you say.

73s Claudio
 
RE: SDR: Good QST artical.  
by N2KFC on May 27, 2008 Mail this to a friend!
Hello John,

You said:"It is interesting to look at various design techniques, and discuss their advantages and disadvantages. "

Yes John...I agree with You...specially now with modern SDR Technology...
SDR Projects like: QS1R ,PERSEUS ,SDR-IP ...with 104/105 dB IMD DR @2kHz separation with 500Hz filter and 125dB BDR...and they can only get better !!!
This is 25 dB better IMD DR ,then old DRAKE R4C !!! 10db better then ELECRAFT K3 and Ten-Tec !!!

John,what are You thinking who will much this level of IMD DR first???ELECRAFT or Ten-Tec ???
I think that Ten-Tec...Ten-Tec has better R&D engineerig staff...
ELECRAFT is stack with outdated narrow roofing filter concept...but this is good for roofing filter companies for sure,first they sell You a Radio for 1400$ and latter set of roofing filters for another 1000$...

We will see...this will be very interestimg to watch...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by N2KFC on May 27, 2008 Mail this to a friend!
Hello Claudio,

How are you?

You said:"I partly agree, the newest generation rigs use good DDS in their synth and a good DDS (when well designed) should be far superior to a free running VFO, especially close-in to the carrier. But I agree that poor designed DDS can have high phase noise, as you say. "

Well...DDS have another problem...spurrs !!!

So far...Ten-Tec synth has the best close in characteristic...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by N2KFC on May 28, 2008 Mail this to a friend!
Interesting News abt ELECRAFT K3...from ELECRAFT Reflector...

"K3 SHUTDOWN on 50 MHz--solution coming soon "

Wow..wow !!!

"K3 Temporary workaroud allows 6-meter operation at high power "

Wow...wow !!!

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by KD8K on May 28, 2008 Mail this to a friend!
>Interesting News abt ELECRAFT K3...from ELECRAFT Reflector...

At least Elecraft is responding quickly to issues! Much quicker then some other companies I know!


I just wanted to offer one further comment on Phase Noise. (This is not meant to be trolling, but I am interested learning more about this subject) I did some research on this issue and found some interesting info. I think my comments earlier on "wide band phase noise" may have been misinterpreted. I did not mean you have to look at wide spaced numbers, but what I meant is that you should not look at just one narrow section of the band (whether close in or wide spaced) but look at the numbers as a whole across the band. I believe that Phase Noise has a cumulative effect. I may or may not be wrong about that. For instance, I noticed these phase numbers comparing the Orion to the K3 that was posted on the K3 reflector...

Rig............1kHz.. 2.. 10.. 10.. 50.. 100.. 1M

K3............ -110 -119 -136 -140 -143 -144 -150
ORION 2... -121 -129 -126 -125 -118 -128 -138

So while yes, the Orion is better at 1 Khz, The Orion could receive Phase noise interference from a signal 5-10 Khz away that the K3 would not receive. Which is better? I am not sure one or the other is better, just different. In a crowded band with many strong signals 25-50 Khz within each other, the K3 may actually have less phase noise problems then the Orion, because the Orion might receive phase noise issues from a signal 5-25 Khz away that the K3 would not. That's what I meant by looking at "wide band characteristics" You have to look at a wide section of the band to see how the receiver will perform in a crowded band situation.In the end, I believe that the Orion would do better is some situations, and the K3 might do better in another. I am NOT an expert on this, so I will throw this out for additional comment...

73,

John, KD8K



 
RE: SDR: Good QST artical.  
by KD8K on May 28, 2008 Mail this to a friend!
Theres a slight mistake in the chart above, the 2nd 10Khz should be 20Khz...

73,


John, KD8K
 
RE: SDR: Good QST artical.  
by N2KFC on May 28, 2008 Mail this to a friend!
Hello John,

How are you today?

When we are testing RX,there are two aspects one theoretical ,one practical...
Most HF Radios have MDS abt -130dBm with 500Hz filter...take your radio and check how many signals at or above 59+30dB you have in your location on the band at the same time...not too many if at all???and all have to be in abt 30khz wide part of band...

Most HF operators are useing too low MDS...use ATTN in ANT line,so you can set noise level from ANT to abt 10-15 dB above RX noise...most of the time you can use 10-30 dB ATTN...most of the time I am useing 10db ATTN even on 21MHz ...I am useing ATTN combination 5-10-10-20 dB ,so I can set in 5dB steps...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by KD8K on May 28, 2008 Mail this to a friend!
>John,what are You thinking who will much this level of IMD DR first???ELECRAFT or Ten-Tec ???
I think that Ten-Tec...Ten-Tec has better R&D engineerig staff...

>ELECRAFT is stack with outdated narrow roofing filter concept...

>104/105 dB IMD DR @2kHz
>125dB BDR


Hi John,

If I am not mistaken, I believe that Ten-Tec also uses roofing filter designs in the Orion and Omni VII, very similar to Elecraft. I am not sure who who will hit 105db first, but Elecraft seems to be closest, only 4-5 db away!. Wayne and Eric are pretty good engineers, just as the guys at Ten-Tec are. I would like to see Rob do some measurements on the Perseus, I think those are similar numbers to what another SDR company claimed and it ended up being less... I still say 125db BDR needs to be improved some, if my calculations are right that is about a 70db over 9 signal, a very strong, but not unheard of signal strength, especially in strong RF Environments. However,With that being said, I am sure that it will be improved, and in the not so distant future old style crystal filters will be a thing of the past!

73,

John, KD8K


 
RE: SDR: Good QST artical.  
by KD8K on May 28, 2008 Mail this to a friend!
Hi John

>Take your radio and check how many signals at or above 59+30dB

I think in a contest situation, that could happen easily!. In any case my point is that the exact same signal not causing Phase noise issues on the Orion at 1Khz can cause a phase noise issue at 10Khz because the Phase Noise gets worse the further out you go. To me, it is pick your poison, do you want a Phase noise problem from a signal at 1Khz or 10Khz? Am I incorrect about that?


73,

John, KD8K
 
RE: SDR: Good QST artical.  
by N2KFC on May 28, 2008 Mail this to a friend!
I am talking abt 104/105 dB IMD DR @2kHz with 500Hz filter!!!

Elecraft and Ten-tec are 10dB behind !!!

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by N2KFC on May 28, 2008 Mail this to a friend!
"I think in a contest situation, that could happen easily!. In any case my point is that the exact same signal not causing Phase noise issues on the Orion at 1Khz can cause a phase noise issue at 10Khz because the Phase Noise gets worse the further out you go. To me, it is pick your poison, do you want a Phase noise problem from a signal at 1Khz or 10Khz? Am I incorrect about that? "

So...next contest...do checking and tell me abt...

I am operating from different locations in The World...and I do not see too many signals at 59+30dB or stronger on HF bands...from USA stations only K3ZO is 59+30dB in Indonesia,sometimes...N3XOF is very strong too...
You see,I know DX Pile-up to South Pacific from both ends...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by KD8K on May 28, 2008 Mail this to a friend!
<You see,I know DX Pile-up to South Pacific

<I do not see too many signals at 59+30dB or stronger on HF bands

I do not claim to have your knowledge of contesting, or DXing; I am sure I can learn much from your experiences! I am just someone interested in the technical aspects of radio...however, I can speak of my experiences..I routinely see signals +30db on 40 and 80 meters almost every night. W1AW hits that here almost every evening; Broadcast stations on 40m hit 40db plus, and from what I hear it is much worse in Europe... During the WPX contest the band had quite a few 30db plus stations when I listened... And I run a simple dipole on 40m, So I don't believe 30db Plus signals is unusual at all in the USA. We can agree to disagree on that however :) I also find it interesting that the Orion at 50Khz the Phase noise is 118db...A signal 50Khz away can cause a significant Phase noise issue on the Orion.

You gave a scenerio from your side, let me present a scenario that occurs with me on the other side of the pileups and this is where I believe the K3 would be better then the Orion because of it's better Phase noise numbers at slightly wider spacings....

I am trying to work a weak DX station listening up 5-10, a fairly common situation...Many strong stations calling...The K3 has better Phase noise numbers at that spacing, (The Crossover point from what I understand is around 5Khz) so the Orion would have a higher potential to have the weak dx station covered by phase noise due to the strong stations calling in the pileup...And from what I understand, it only takes 1 strong signal to cause Phase Noise issues...Once again, it may come down to what is important for the way we operate, but that is why It was important for me to look at the whole bandwidth of the Phase noise, and not just one narrow slice. If I am incorrect on that, let me know!



>I am talking abt 104/105 dB IMD DR @2kHz with 500Hz filter!!!

Fair enough, I still would like to see some independent tests that have been done by either by Rob or the ARRL and then we would have something concrete on which to discuss!

73,

John, KD8K


 
RE: SDR: Good QST artical.  
by N2KFC on May 28, 2008 Mail this to a friend!
Hello John,

It is OK...so you have a few strong signals at 40mtrs...but like I said use some ATTN in ANT line and problem is gone...I am sure that you have very high antenna noise level on 40mtrs,you can use 20dB or even more ATTN...
Most of the time in my New York city location even on 20 mtrs,ANT noise level is abt -100 dBm in 500Hz I can use easy 15dB of ATTN...
Wide band ANT noise 0-32 MHz ia abt -17dBm...wide band noise from ANT in 0-32 MHz tested with just single Pole LC Preselector is abt -50 dBm...so,in my location RX with -130 dBm MDS in 500 Hz with -15 ATTN is working just fine...

You said:"Fair enough, I still would like to see some independent tests that have been done by either by Rob or the ARRL and then we would have something concrete on which to discuss! "

Take a look at PERSEUS test done by Leif SM5BSZ...

http://www.nitehawk.com/sm5bsz/perseus/perseus.htm


73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by N2KFC on May 28, 2008 Mail this to a friend!
John,take a look at SM5BSZ Page:

Real life dynamic range
of Modern Amateur Transceivers


http://www.nitehawk.com/sm5bsz/dynrange/dubus205/dubus205.htm



It is not only Rob and ARRL...we are doing a lot of testing in Europe too...now situation is much different,thousands of Hams have commercial test equipment in their Radio Shacks...


73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Good QST artical.  
by KD8K on May 29, 2008 Mail this to a friend!
> like I said use some ATTN in ANT line and problem is gone...I am sure that you have very high antenna noise level on 40mtrs,you can use 20dB or even more ATTN.

>most of the time in my New York city location even on 20 mtrs,ANT noise level is abt -100 dBm in 500Hz I can use easy 15dB of ATTN.

Good point, and I do use the ATTN most of the time on the K3 when using 80m and 40m. That is one thing about
the K3 I do not like, it only has a 10db ATTN, I wish it had more selections. So in the end, I would think that the K3's 1Khz and the Orion's 10Khz and 50Khz Phase noise numbers are not as much of a issue when you take into account the things you mentioned above.

>It is not only Rob and ARRL...we are doing a lot of testing in Europe too..

I certainly did not mean to imply that test results are only done in the USA. My point is that it is hard to compare test results between different individuals because of possible differences in test methodologies... for instance, read this about the K3 from test results that was done in Europe.

http://www.bavarian-contest-club.de/projects/K3_english.pdf


If I am reading that chart correctly, it lists the K3's IMDDR3 at around 106-107db! So my point is that I would like to compare the Perseus using numbers by the same individual because of possible variations in testing. Nothing against the Perseus, it looks like a fine and interesting radio.


>Real life dynamic range
of Modern Amateur Transceivers

>http://www.nitehawk.com/sm5bsz/dynrange/dubus205/dubus205.htm

That does look interesting, There is a lot there though, I will read it after work today!


73,

John, KD8K
 
RE: SDR: Good QST artical.  
by N2KFC on May 29, 2008 Mail this to a friend!
Hello John,

Yes...only 10dB ATTN it is not enough...but you can make your own outside with some relays and put in ANT line and use some control signal from K3 to switch btw TX/RX...

I know page of Bavarian club...yes their data is "off" the mark...

Yes,take a good look at SM5BSZ and LINRAD ,a lot of up to date info abt Ham Radio...

73!
John/sp2ggz/n2kfc/yb1aqv
 
SDR: Ham Radio of the Future?  
by NR9R on May 29, 2008 Mail this to a friend!
Thank you for taking the time to share your thoughts Claudio.

One point I would like to make is the difference between the "quality" of the receive audio and "utility" of the receivers function.

Let's say "quality" is related to how pleasurable the audio device is to listen to. One might describe an audio amplifier or radio receiver that produces rich life-like tones as high in quality.

Let's say "utility" is related to the sensitivity and selectivity of the device. Such a device would be engineered to maximize the ability to discern a signal in the presence of noise; to maximize intelligibility.

In some cases the "quality" and "utility" of a receiver may be mutually exclusive. For instance, noise reduction DSP technology which maximizes the utility of a receiver may be rather unpleasant to listen to while improving intelligibility. Conversely, high fidelity audio which requires a large bandwidth may come at the cost of selectivity.

Whether DSP or analog devices are inherently more apt in maximizing "quality" or "utility" is up for debate. While DSP has potential advantages over analog devices in the area of "utility" it is interesting to note that DSP technology found in pro audio gear attempts to duplicate the "quality" of vintage vacuum tube equipment. The advantage being in the ability to select several classic sounds in a single digital device at a fraction of the cost (Do digital audio devices even have a revered character of their own?)

So I guess it comes down to how one plans to use a radio receiver. SDR may be an ideal technology for contesters while a vintage vacuum tube receiver may not be surpassed in terms of quality. Unless of course the digital receiver is successfully programmed to duplicate the analog sound.

Anthony

 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 30, 2008 Mail this to a friend!
Hello John,

Direct sampling SDR receiver measurements &#8211; IK1ODO


http://www.guyatkins.com/files/sdr/SDR_RX_measurements.htm


John...where is Rob??? he is getting slow in responding to modern RX Technology ???

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 30, 2008 Mail this to a friend!
Hello John,

Take a look...Mixers testing done by PA3AKE...


"http://www.xs4all.nl/~martein/pa3ake/hmode/index.html"

You can see what mixers we are useing for long time,with Input IP3 50dBm+

ELECRAFT K3 has only IP3 +26dBm...my 40yrs old RACAL RA1772 has IP3 +30dBm with preamp on !!!

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 30, 2008 Mail this to a friend!
Hello John,

Interesting Mixer by RZ4HK...


http://www.xs4all.nl/~martein/pa3ake/hmode/tlt-hmode.html


73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by KD8K on May 30, 2008 Mail this to a friend!
Hi John


>ELECRAFT K3 has only IP3 +26dBm...

That's still better then the +21 of the Orion II :) (I still think that they both have excellent numbers and are both great rigs!)

>Direct sampling SDR receiver measurements
>http://www.guyatkins.com/files/sdr/SDR_RX_measurements.htm

Those are excellent numbers.I do notice that it lists the Perseus as 102db IMD, not 107db, and 118db BDR not 125db, once again differences in measuring methods or sample variation? For me, it's hard to compare numbers from different individuals for that reason. Whether it's 102 or 107, they are both excellent numbers. Do you think that -107db or -123dm noise floor is enough for picking up weak signals? I think a preamp might be needed in some situations.




73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by KD8K on May 30, 2008 Mail this to a friend!
That should have been 105db, not 107db for the above...

Hi John,

<Interesting Mixer by RZ4HK...


<http://www.xs4all.nl/~martein/pa3ake/hmode/tlt-hmode.html



Yes, that does indeed look interesting. As you mentioned before the numbers have got so high that because of band noise, etc there may be no practical benefit, but still interesting none the less...

73,

John, KD8K



 
RE: SDR: Ham Radio of the Future?  
by N2KFC on May 30, 2008 Mail this to a friend!
Hello John,


"Those are excellent numbers.I do notice that it lists the Perseus as 102db IMD, not 107db, and 118db BDR not 125db, once again differences in measuring methods or sample variation? For me, it's hard to compare numbers from different individuals for that reason. Whether it's 102 or 107, they are both excellent numbers. Do you think that -107db or -123dm noise floor is enough for picking up weak signals? I think a preamp might be needed in some situations. "

IMD on this list are from calculation...see the note...
SM5BSZ data are from test...

Take a look...118dB BRD is for 2400 Hz filter!!!

QS1R is tested without Preamp...so everything is OK...

Yes,PERSEUS AND QS1R numbers are great...

So, now you have good idea what is the state of art in Analog and Digital RF Technology.

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by KD8K on May 30, 2008 Mail this to a friend!
Hi John,


<Take a look...118dB BRD is for 2400 Hz filter!!!

Doesn't the BDR typically stay the same on a SDR regardless of filter size or spacing, or am I wrong about that? If that's the case, it would not matter if it is measured with a 500hz or 2400hz filter setting

73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by KD8K on May 30, 2008 Mail this to a friend!
Hi John,

>So, now you have good idea what is the state of art in Analog and Digital RF Technology.

Thank you for your input, as always John!

My view is that SDR is outstanding in many different way's and will only get better. Being able to manipulate a RF signal with software is very powerful. As you said, the numbers are so high now that additional improvement will not have a lot of practical benefit. (It's still fun to compare numbers though!) I doubt many would be able to tell the difference between a Perseus, Flex 5000, K3 or Orion in the real world. A lot of it comes down to User interface issues and personal preference. For a minority of us (or perhaps I am the only one?), BDR is still somewhat of a issue, but that has improved will continue to be improved over time. It will be interesting to see how SDR evolves over time.

73 for Now,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 1, 2008 Mail this to a friend!
Hello John,

"Doesn't the BDR typically stay the same on a SDR regardless of filter size or spacing, or am I wrong about that? If that's the case, it would not matter if it is measured with a 500hz or 2400hz filter setting "

No...if you change filter bandwidth you are changing MDS level of your RX at the same time !!!
You will have bigger DR with narrow filter !!!
This is why ELECRAFT is comparing IMD DR of ELECRAFT K3 with 200Hz filter to Radios with 500Hz filter...just little "dirty trick"
You have to give filter bandwidth for BDR and MDS testing !!!

Yes modern SDR's are very good now,and thousands of Hams are useing SDR Radios today...

John...do you have Band Scope for your K3???

73!
John/sp2ggz/n2kfc/yb1aqv

 
RE: SDR: Ham Radio of the Future?  
by S5M on June 1, 2008 Mail this to a friend!
KZ1X: Wonder why the top two receivers on Rob Sherwood's reports are US-made SDRs?

Rob is in add-on filters business and he measures 2 kHz IMD! I only experienced such heavy QRM during WRTC-1996 in Silicon Valey. Read G3RZP for the rest.

My old IC-735 had bad AC hum and a lot of hiss. Adding outboard 300-3000 Hz DSP filter made it dream RX! Nothing changed on the radio side, just my perception. Aviators learn early to trust instruments. Audiofiles like the "warm" sound of tubes :-)

Collins makes VHF SDR but uses superhet front-end on HF. Still the only way to survive in close multi-TX environment.

73 de Mario, S56A, N1YU, MSc EE retired
 
RE: SDR: Ham Radio of the Future?  
by S5M on June 1, 2008 Mail this to a friend!
KD8K: Being able to manipulate a RF signal with software is very powerful.

The minor problem is that RF signals are of analog electrical nature and should be converted to bits first within a reasonable sampling time. We can do it with 16 bits for HF but beware that Morse dot is only 30 msec long limiting software FFT BW resolution.

I hope you are aware of excelent RSGB G3SJX tests. DARC CQ DL lab is also less concerned about advertising revenues then ARRL. Rob is patriot :-)

Check SM5BSZ decent IMD chart which shows SDR collapsing totally around 0 dBm input because of ADC saturation. No SDR at USA M/M superstation yet!

BTW, I still have to switch DSP functions on my FT1K. I did my homework in 1990's on CW DSP.

73 de Mario, S56A, N1YU
 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!
<John...do you have Band Scope for your K3???

Yes, actually I do!. The K3 has a IF output which is fed into a softrock. I am waiting on my LP-PAN, it should be here next week. Both allow the K3 to be used with with various SDR software, including a modified version of Powersdr by WU2X. This allows full point and click tuning on a 192 KHZ bandscope! I click on the signal in Powersdr and it tunes the K3 to that frequency! I have also been using WinRAD with the K3, that seems like real nice software also. Once again, this is a personal preference but, this is what I like best, I do not like being limited to computer control only, but I still have the benefits of most of the SDR Software out there. After using my SDR-1000 for a while, I just could not get used to only computer control, although it does have advantages for some things.

73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 1, 2008 Mail this to a friend!
Hello John,

How are you today???

So,you have PAN Display...very good...so we can do some testing...what audio card do you have???
Without ANT signals,is your noise response on the Display flat???

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!
<Check SM5BSZ decent IMD chart which shows SDR collapsing totally around 0 dBm input because of ADC saturation. No SDR at USA M/M superstation yet!

If I am not mistaken 0dbm is around S9+70, so that would explain the problem I had with the Flex. That describes exactly what would happen, the receiver would appear to "saturate" from the strong signal, making the SDR-1000 unusable.

73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!
>what audio card do you have?

EMU-0202

>Without ANT signals,is your noise response on the Display flat???

96Khz, perfectly flat. 192Khz, has a slight bump on the edges that goes away with ANT noise. This is on the softrock. The LP-PAN from what I understand is much better then the softrock. I will find out when I receive it next week

73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 1, 2008 Mail this to a friend!
Hi John,

This is OK...

Now...do you have RF ATTN ???
Do you have some low power RF source:RF Generator ,Crystal OSC or LC OSC ???
Do you have Second Computer???

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!
>Now...do you have RF ATTN ???
Only on the K3

>Do you have some low power RF source:RF Generator ,Crystal OSC or LC OSC ???
Yes

>Do you have Second Computer???
Yes

I might be able to save us both some time; please see
http://www.telepostinc.com/ under lp-pan, Larry has a description of LP-PAN using the emu-0202 and PowerSDR and some test results.

Also, remember, I use this primarily as a bandscope! I receive via the K3, so the actual receive performance of the LP-PAN or Softrock is not that important to me.


73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 1, 2008 Mail this to a friend!
Hi John,

LP-PAN -I konw this page,very interesting,not only for ELECRAFT K3 use...


What kind of RF Source do you have???

What IF Filters do you have in your K3???

This can be very interesting to compare K3 to SDR with K3 Front End...I am getting some reports that SDR with K3 Front End is better then ELECRAFT K3 !!!Very interesting !!!Maybe K3 has some Mixer termination problems ???

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!

>No...if you change filter bandwidth you are changing MDS level of your RX at the same time !!!
You will have bigger DR with narrow filter !!

That's an interesting question to me now, because I thought blocking dynamic range was the difference between the receiver's noise floor, and the blocking signal, measured in DB. I thought that when the MDS changes, the dynamic range stays the same, it's just that the "Window of dynamic range"(whether it be 123db or 139db moves) so if the MDS is -124db the Blocking DR is 123db above that, or if the MDS is -130 the Blocking DR is still 123db above that. For example, It's interesting to me that the Flex 5000 has a 119dbm MDS preamp off and 132dbm preamp on on 14mhz and only 1 db difference in blocking DR (123/122) As I said before, I am not a expert on this, so perhaps I have the wrong understanding on this.

73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!
>I am getting some reports that SDR with K3 Front End is better then ELECRAFT K3 !!!Very interesting !!!Maybe K3 has some Mixer termination problems ???

Personally I would much rather rely on documented test results! In any case, I can guarantee that the K3's front end is far superior to that of a softrock!

73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 1, 2008 Mail this to a friend!
Hi John,

"That's an interesting question to me now, because I thought blocking dynamic range was the difference between the receiver's noise floor, and the blocking signal, measured in DB. I thought that when the MDS changes, the dynamic range stays the same, it's just that the "Window of dynamic range"(whether it be 123db or 139db moves) so if the MDS is -124db the Blocking DR is 123db above that, or if the MDS is -130 the Blocking DR is still 123db above that. For example, It's interesting to me that the Flex 5000 has a 119dbm MDS preamp off and 132dbm preamp on on 14mhz and only 1 db difference in blocking DR (123/122) As I said before, I am not a expert on this, so perhaps I have the wrong understanding on this. "

If you add PREAMP this is different story...depends how many dB of amplification and another factor Noise Figure of PREAMP...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 1, 2008 Mail this to a friend!
Hi John,

"Personally I would much rather rely on documented test results! In any case, I can guarantee that the K3's front end is far superior to that of a softrock! "


Well...I am not so sure...Softrock is pretty good !!!
Like we said before ELECRAFT K3 has ONLY +26dBm Input IP3 !!! K3 Mixer configuration has very easy capacity of +40 dBm Input IP3 ,something is wrong with K3 Mixer or Mixer termination or IF System ???or all of them ???

John...do some testing...connect other SDR to Audio output of ELECRAFT K3...set widest IF Filter in K3 and set DSP Filter for 500Hz...turn off analog and digital AGC in ELECRAFT K3...in PAN display SDR turn of AGC,and set SDR Filter for 500Hz...set sdr conditions for similar noise pick-up from ANT...
Go to busy BAND and compare two RX's...maybe we will find out what ELECRAFT IS HIDDING behind narrow 200Hz IF Filter???

Get some ATTN's so we can do a lot of very interesting testing...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 1, 2008 Mail this to a friend!
Hello John,

John...get a book:"Radio Communications Receivers" by Cornell Drentea ,this is the best,comprehensive guide to radio receiver design and technology!

73!
John/sp2ggz/n2kfc/yb1aqv

 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 1, 2008 Mail this to a friend!
Hi John,

Take a look at SYNERGY MICROWAVE Page:


www.synergymwave.com


Very good source of up to date Info abt RF Technology...
Company is run by Ulrich N1UL...they are making very iteresting things...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!
>ELECRAFT K3 has ONLY +26dBm Input IP3 !!!
>something is wrong with K3

Do you think that is a bad number? The Orion is at +23dbm! If there is something wrong with the K3, then what is wrong with the Orion?


73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!
>if you add PREAMP this is different story...depends how many dB of amplification and another factor Noise Figure of PREAMP...

Does the dynamic range actually change when you add a attenuator(thus affecting the radio's MDS)?

73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 1, 2008 Mail this to a friend!
Hi John,

"Does the dynamic range actually change when you add a attenuator(thus affecting the radio's MDS)? "

No...you only shift MDS UP...


"
Do you think that is a bad number? The Orion is at +23dbm! If there is something wrong with the K3, then what is wrong with the Orion? "

It is not a matter of good or wrong...this is good or bad engineering...for what to use Mixer with +40dB Input IP3 in +26 dBm RX if you can use very cheap diodes DBM ???

73!
John/sp2ggz/n2kfc/yb1aqv



 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 1, 2008 Mail this to a friend!
Hi John,

Some "Real Live" testing done today in NYC on 20Mtrs...useing Commercial HP3586 Level Meter

Total power at ANT Connector:

1. -23dBm in 0-32MHz Bandwidth
2. -50dBm in 0-32Mhz Bandwith with single LC Preselector
3. -38dBm in 0-32MHz Bandwidth with 14MHz ,3el ,HP Filter
4. -103dBm in 400Hz Filter
5. -40dBm when 4U1UN/B is on

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!
< No...you only shift MDS UP

That's exactly what I understood, changing the MDS does not change the DR, it shifts it... So again, does a lower MDS due to a increased bandwidth setting on a SDR actually change it's Dynamic Range or is it Just "Shifting the Dynamic Range" (Actual dynamic range stays the same)


>Some "Real Live" testing done today in NYC on 20Mtrs...using Commercial HP3586 Level Meter

That's interesting info, but not really applicable for my situation as I do not live in NYC :) I live close to another ham who I regularly get a s9+70db+ signal from, and that's my concern in using a SDR.

>it is not a matter of good or wrong...this is good or bad engineering

So are you also saying that the Orion is engineered badly?



I guess we have taken a lot of bandwidth on this thread. Would you like to continue our discussion off list?


73,

John, KD8K


 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!
sorry, that should have been "higher MDS" in the above.
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 1, 2008 Mail this to a friend!
Hi John,
"That's exactly what I understood, changing the MDS does not change the DR, it shifts it... So again, does a lower MDS due to a increased bandwidth setting on a SDR actually change it's Dynamic Range or is it Just "Shifting the Dynamic Range" (Actual dynamic range stays the same) "

This is just oposite,if you incrase bandwdth,you will get more noise!!!MDS will have higher value and DR will be lower!!!
If you change noise bandwith from 500Hz to 200Hz...this is 2.5 times...you will gain 4dB in DR !!!
You have to specify bandwidth if you compare DR !!!

" I live close to another ham who I regularly get a s9+70db+ signal from, and that's my concern in using a SDR. "

Before you said 59+60dB...this is why you need ATTN so we can test signals levels in your location...SDR is not only RX,but very good test equipment too,with additional ATTN we can test higher levels...
59+70dB ,this is -3dBm signal,abt range of BDR of SDR PERSEUS !!!You need some ATTN in ANT Line anyway...

Like you see ,modern SDR's are very good...problems of Multi operators,multi-multi KW's TX's ,are not our problems !!! If somebody is running only a few dB less Power then Local MW Broadcast Station...well this is his problem...

73!
John/sp2ggz/n2kfc/yb1aqv

 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!
<This is just opposite,if you increase bandwidth,you will get more noise!!!MDS will have higher value

See my previous post, I corrected and said higher...



>Before you said 59+60dB

No, I said GREATER THEN 59+60. I am not sure of the exact strength but Judging from the fact it is blocking, a good estimation is at least 59+70 or around 0dbm.


I think we are just going to have to agree to disagree John... I think we have been discussing this issue long enough, I will let others have the bandwidth now! :)

73,

John, KD8K

 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 1, 2008 Mail this to a friend!
Hi John,


>You have to specify bandwidth if you compare DR !!!

John, the point I am trying to make is that SDR filtering is not the same as Analog Filtering. To me, changing a filter size in a SDR is not the same as changing a filter size in a analog radio. Changing a filter, say in Winrad, is not the same, as say, selecting a different crystal filter in a TS-450 or some other analog radio.

As you know, in a SDR, a full bandwidth of signal (often 198khz or better) is applied to a Analog to Digital Converter. Software does processes a portion of that frequency range, but a wide range of frequencies is still being applied to the ADC, before the software even processes it! The dynamic range of the SDR is typically the dynamic range of the ADC. That is my understanding, the dynamic range of the SDR is not in the software, not in what filter sizes that are selected, but in the Hardware, in the ADC. That's why I say software filter sizes don't really matter that much in a SDR. You keep mentioning filter sizes and DR, but to me, if you know the dynamic range of the ADC, then you know the dynamic range of the SDR. To me, it's simple, actually!

Also, if you need more then 123db blocking that the currently used ADC's typically have, then you put something in front of the ADC to protect it. Again, rather simple to me! This is especially true when a very large range of frequencies are applied to the ADC, more chance of a signal saturating the ADC.


As I said previously, I think I have used enough bandwidth on this thread, so I will make that my last comment. I have enjoyed our Discussion John!

73,

John, KD8K

 
RE: SDR: Ham Radio of the Future?  
by NC0B on June 1, 2008 Mail this to a friend!
Since my name and my web site have been mentioned several times in this forum, I thought I would make a few comments. My testing of radios, beginning in 1976, happened by accident. I purchased an R-4C that tested well at 20 kHz, but performed poorly in a CW contest. Thus I originated the 2-kHz dynamic range test in that year, since it differentiated how radios really performed in CW pile-ups. It took decades for the League to react to the fact that a 20-kHz test alone was inadequate.

All radios are not in my chart since I certainly could not afford to buy everything on the market. Many were borrowed from CW Electronics, now HRO, in Denver, while others were sent in by hams willing to loan a radio for testing purposes. It is a free service with no advertisers and no potential conflict of interest.

I think there is some hair splitting at the level of performance we now have on the market. A few dB one way or another would never be noticed in the heat of battle during CQ WW. The Flex 5000A was tested with a 500 Hz DSP bandwidth. It also has a flat phase noise characteristic, not one that generally falls off (improves) at 6 dB per octave at wider spacing. You can see this confirmed by the ARRL report now on the web. Likewise the Orion has a bump at 50 to 60 kHz in phase noise, and its phase noise is different on each band, due to the division of the LO. The K3 varies from 95 to 101 depending on the combined roofing filter and DSP bandwidth. The total bandwidth of an Orion or a K3 is less than the individual bandwidth of the roofing filter and the DSP setting. The data is also a single sample, so there will be sample variations to a modest degree.

What I am trying to say is look at the big picture. The Atlas 350-XL happens to be 9th on the chart, but that does not mean that it is better than all those below it. The chart had to be sorted by some column, and I felt that close-in dynamic range was the biggest differentiator of radios for the CW operator. The Atlas ranks above the Icom IC-7800, but obviously the $10,599 Icom has a lot more in its arsenal to combat QRM. It is also interesting that the top radios are 15 dB better than this very expensive Icom.

The League has changed the way it now measures blocking, and I used their method for testing the K3 only. Unfortunately the number is meaningless, and I will be inserting a footnote in the future to explain why. Most modern radios are phase-noise limited before they block, meaning that reciprocal mixing noise coming out the speaker overshadows gain compression. To solve this measurement problem, the League decided to look at the weak signal being blocked with a very narrow audio spectrum analyzer. Maybe they listen to weak CW signals on the air with a 3 or 10 Hz spectrum analyzer, but I don’t. Sometimes new testing methods don’t make it easier to make a purchase decision.

On my home page there is a Power Point presentation, and the associated audio file, from a talk I gave at the Boulder (Colorado) Amateur Radio Club in February. This lead to an expanded version for K3LR’s Contest University, just before the 2008 Dayton Hamvention. These slides and audio file will be available soon for download.

One subject that is discussed in both presentations is the fact that a radio’s dynamic range is a “window” that can be moved around. It is rare that the noise floor of a radio is the limit in reception, and certainly never below 20 meters. If your radio is on the verge of overload on 40, 80 or 160 meters, use your attenuator and reposition the dynamic range to your advantage.

After you read the reviews, and look at the charts, then the hard part begins. What is important to the buyer? What modes are going to be used? Do you want to run your radio with a computer? Do you have big hands and like big knobs? What about reliability and service support? Does the AGC over-react to transient noise? Is the blanker effective? Is the audio clean, and how the does the radio perform in QRN and noise? Many DSP radios are not at their best in noise.

Close-in dynamic range requirements are vastly more significant on CW than SSB. (The presentations explain why.) Even on CW, the limit as to how close one can operate to a very strong signal may be limited by the keying sidebands of the strong station 1 kHz away.

There is no way to put all this information in a table. But you can decide not to buy a radio with a 63 dB 2-kHz dynamic range, if you want to seriously compete in a CW contest. Why are 63 dB radios even be produced in 2008? W8JI and I both agree that if your radio has a close-in dynamic range in the mid 80s, you will be happy most of the time. If you want a 10 dB safety factor, at least you now have that option, and interestingly enough, they are all American made!

73, Rob Sherwood, NC0B
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 2, 2008 Mail this to a friend!
Hi John,

"John, the point I am trying to make is that SDR filtering is not the same as Analog Filtering. To me, changing a filter size in a SDR is not the same as changing a filter size in a analog radio. Changing a filter, say in Winrad, is not the same, as say, selecting a different crystal filter in a TS-450 or some other analog radio. "

Well...filters are analog or in software, but in the end are doing the same...you just need some time to understand this...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by N8VB on June 2, 2008 Mail this to a friend!
"You keep mentioning filter sizes and DR, but to me, if you know the dynamic range of the ADC, then you know the dynamic range of the SDR. To me, it's simple, actually!"

This is incorrect. Google for "processing gain" to see why your statement is not true.

Phil N8VB
http://www.srl-llc.com
 
RE: SDR: Ham Radio of the Future?  
by W4ZV on June 2, 2008 Mail this to a friend!
Regarding phase noise, here's a summary of TX phase noise made by Eric WA6HHQ of Elecraft last September. Note that I added the FLEX 5000 results by visually interpolating Figure 3 of ARRL's July 2008 Product Review.

#######################################################
http://www.nabble.com/K3-and-pahse-noise-td14082921.html#a14082985

Here are transmit composite phase noise numbers from the Lab for the K3.
Needless to say, we are pleased with the results. :-) I've also included
some numbers from the ARRL reviews for several late model rigs.

Rig 1kHz 2 10 20 50 100 1M
K3 -110 -119 -136 -140 -143 -144 -150
IC7800 -103 -112 -130 -138 -140 -140 -140
FT2000 -102 -105 -128 -129 -128 -128 -128
ORION 2 -121 -129 -126 -125 -118 -128 -138
OMNI 7 -102 -103 -120 -123 -127 -129 -126
FLEX5K* -116 -118 -119 -118 -118 -117 -118

*interpolated from Fig 3, ARRL July 2008 review

Note:
All of the above data reflect the ARRL's latest phase noise lab test set
up. The K3 was tested on an identical set up which has been correlated
with the ARRL's. The ARRL changed to this more accurate phase noise test
set up with the IC7000 Review in May of 2006. (See the sidebar in the
IC-7000 review, on pg 71, for details covering this change.)

Phase noise results from reviews prior to May 2006 were off by 7.5 dB
(too optimistic). When comparing new phase noise results to the old
ones, move upward on the chart 7.5 dB from the old number. (i.e. For an
old phase noise number of -110 dB, the corrected value is 110-7.5 =
-102.5 dB.)

The new phase noise plots are easy to spot as they extend to 1 MHz,
versus the 22 kHz limit of the old ones. All of the above data are from
the new test method.

73, Eric WA6HHQ
#################################################

Which radio has the best phase noise? It depends on the spacing. Orion is best at close spacings but the K3 is best integrated over a wide range. I once believed Ten-Tec did the right thing optimizing Orion's close-in phase noise but have changed my opinion. Close-in RX performance is so dominated by other issues like key clicks that phase noise issues are over-ridden. Thinking about an intense contest environment such as the CQ 160 CW Contest, where you have 50-100 kHz full of S9+30 stations spaced every few hundred Hz, I believe the best metric may be phase noise integrated over the frequencies of interest, since all signals will be contributing to noise in your receiver.

73, Bill W4ZV
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 2, 2008 Mail this to a friend!
Hello Bill,

"Which radio has the best phase noise? It depends on the spacing. Orion is best at close spacings but the K3 is best integrated over a wide range. I once believed Ten-Tec did the right thing optimizing Orion's close-in phase noise but have changed my opinion. Close-in RX performance is so dominated by other issues like key clicks that phase noise issues are over-ridden. Thinking about an intense contest environment such as the CQ 160 CW Contest, where you have 50-100 kHz full of S9+30 stations spaced every few hundred Hz, I believe the best metric may be phase noise integrated over the frequencies of interest, since all signals will be contributing to noise in your receiver. "

Like you said :"50-100 kHz full of S9+30 stations" ,yes but you need a lot of stations in just right place...on 160 Mtrs we can make very easy very good LC Preselector...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 2, 2008 Mail this to a friend!
Hello Bill,

I am getting a lot of reports that ELECRAFT K3 is not working to good if you set wide Roofing filter,SSB or wider and 500Hz DSP filter...I am sure you did some testing with these settings...what are you thinking???
I did very short testing of K3 myself and I "fill" clear degradation...
I have Home Made SDR with First IF of 9MHz and I do not have this problem...I can use 500Hz filter or 100KHz filter in my IF...no big difference...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by W4ZV on June 2, 2008 Mail this to a friend!
"Like you said :"50-100 kHz full of S9+30 stations" ,yes but you need a lot of stations in just right place...on 160 Mtrs we can make very easy very good LC Preselector..."

I don't think so. I'm referring to 1800-1850 kHz filled with S9+30 contest signals every 3-500 Hz. There is no LC pre-selector I'm aware of that can pass desired signals while rejecting undesired signals a few hundred Hz away. Only crystal filters can do that. Also, IMD does require signals in "just the right place" but phase noise is broadband.

"I am getting a lot of reports that ELECRAFT K3 is not working to good if you set wide Roofing filter,SSB or wider and 500Hz DSP filter...I am sure you did some testing with these settings...what are you thinking???
I did very short testing of K3 myself and I "fill" clear degradation...
I have Home Made SDR with First IF of 9MHz and I do not have this problem...I can use 500Hz filter or 100KHz filter in my IF...no big difference..."

If you are not seeing the problem in your homebrew rig it's because the QRM signals may not be strong enough to activate DSP protection. Every DSP rig must have this or it will drive the ADC in the DSP into overload. As has already been discussed, BDR in the Flex-5000 is ~123 dB versus ~140 dB in the K3 (per Sherwood's measurements).

The ideal case will be with a roofing filter to match the DSP bandwidth, so I would never consider a contest like the CQ 160 CW without a mode-appropriate roofing filter (500 Hz or less).

I find it interesting to compare actual contest results rather than debating theoretical arguments. Below are two such results in the recent ARRL DX Contest on 160 meters.

Call QSOs Mults Score

W4ZV 312 74 69,264
K1LT 214 67 43,014

I was using the K3, unassisted class (no Packet) and single-wire Beverages. K1LT was assisted class (with Packet) using 4 SDR rigs in a 4-vertical beam-steering arrangement described in his Dayton paper below.

http://www.kkn.net/dayton2008/beam_steering_on_160_meters.pdf

Contests on 160 are mainly a test of receiving capabilities, yet I very seldom see the calls of people making theoretical arguments for SDRs in these results. When I see winning contest results by people using SDR rigs, then I'll be convinced. :-)

73, Bill
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 2, 2008 Mail this to a friend!
Hello Bill,

"I don't think so. I'm referring to 1800-1850 kHz filled with S9+30 contest signals every 3-500 Hz. There is no LC pre-selector I'm aware of that can pass desired signals while rejecting undesired signals a few hundred Hz away. Only crystal filters can do that. Also, IMD does require signals in "just the right place" but phase noise is broadband. "

Well...if you have multiple very strong signals in the band ,good preselector will always help...if you have really strong signals...

"Contests on 160 are mainly a test of receiving capabilities" ...well,160mtrs is not so bad in USA ,in Indonesia we have much worst conditions ,a lot of noise...I did a lot of 160 mtrs testing with YB1A from his station...I think that 160mtrs is not so difficult and attractive like some People are thinking...

Well,when I am in South Pacific I am DX mayself...I think that DX Pile-up for DX Station is much more difficult that 160mtrs contesting !!! I know DX Pile-up very well from both ends...With my SDR I do not have problems on HF !!!

The best test of receiving capabilities is 144MHz VHF Contest ,specially in Europe...you will never have so strong signals on HF...we have signals over 160dB over MDS of our Receivers...to copy very weak signals is very difficult !!! But I am useing cavity Preselector ,yes I have to tune this filter ,ultra low noise XO ,and bank of IF filters on 9MHz + SDR...

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by S5M on June 2, 2008 Mail this to a friend!
Bill & Bob, please note that Hilberling PT-8000 with 100 W output finally got FCC license so you might add it to your DL hardware Mercedes and Optibeam :-)

SDR DSP processing gain helps with narrow weak signals but ADC is useless with strong input causing overflow.

Solid state TX are weak link these days with IMD and wideband noise. The most difficult band is 2 meters. 160 m with S9+30 signals is a big joke as we can operate with 40 dB antenna attenuation except in one exceptionally quiet site in GA. Good CW operator ears count more than DSP!

73 de Mario, S56A, N1YU
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 2, 2008 Mail this to a friend!
Hello Mario,

"Solid state TX are weak link these days with IMD and wideband noise. The most difficult band is 2 meters. 160 m with S9+30 signals is a big joke as we can operate with 40 dB antenna attenuation except in one exceptionally quiet site in GA. Good CW operator ears count more than DSP! "

Yes ,Mario ,I agree..."The most difficult band is 2 meters. 160 m with S9+30 signals is a big joke "

40 mtrs in Europe ,is the most difficult to operate HF Band in The World...Very strong Broadcast Stations in Band and around...HF in USA is like a Picnic !!!

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 2, 2008 Mail this to a friend!
Hello Bill,

"If you are not seeing the problem in your homebrew rig it's because the QRM signals may not be strong enough to activate DSP protection. Every DSP rig must have this or it will drive the ADC in the DSP into overload. As has already been discussed, BDR in the Flex-5000 is ~123 dB versus ~140 dB in the K3 (per Sherwood's measurements). "

Well...this take place with not so strong signals,well below saturation of Elecraft K3 front end...simply K3 does not have very good DR in the channel of the roofing filter...that all !!!

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by KD8K on June 2, 2008 Mail this to a friend!
<This is incorrect. Google for "processing gain" to see why your statement is not true.

Thanks for that info Phil. So if understand correctly, the Dynamic Range of the SDR is actually the Dynamic Range of the ADC + the processing gain in the software. Thats why a ADC that has around 100db DR can actually have a DR of 123db. Also, if I understand what I read correctly, there is still a hard limit on the dynamic range, it's just that processing gain improves that limit. My question becomes, does filter size affect the processing gain. In other words, if the ADC+processing gain = 123db dynamic range, and I have say a 125 db signal on the input of the ADC, will changing the filter size to a smaller filter improve the blocking DR on the SDR and perhaps preventing the blocking from occurring, or does it stay the same. I thought it stayed the same, regardless of filter size, and was the point of my previous comment, but perhaps I am wrong about that? If it does change the DR, then that is something I did not know.

73,

John, KD8K
 
RE: SDR: Ham Radio of the Future?  
by S5M on June 3, 2008 Mail this to a friend!
N2KFC wrote: 40 mtrs in Europe ,is the most difficult to operate HF Band in The World...

G3RZP did QEX measurements and came with modest 40 m requirements of IP3=20 dBm with preamp and antenna attenuator. We must have preamp for NF=2 dB on 2 m while we can live happily with NF=20 dB at 40 m. BCI TX WB noise is often a problem here even if it comes from Radio Vatican :-)

73 de Mario, S56A, N1YU


 
RE: SDR: Ham Radio of the Future?  
by N2KFC on June 3, 2008 Mail this to a friend!
S5M Wrote:"G3RZP did QEX measurements and came with modest 40 m requirements of IP3=20 dBm with preamp and antenna attenuator. We must have preamp for NF=2 dB on 2 m while we can live happily with NF=20 dB at 40 m. BCI TX WB noise is often a problem here even if it comes from Radio Vatican :-) "

Hello Mario...on 144Mhz for Troposcatter work ,we need abt NF=3dB ,but from very noisy location like New York City you can use NF=6dB...I think ,I am in the worst VHF Location in The World !!! less then 2miles East of
Manhattan !!!

73!
John/sp2ggz/n2kfc/yb1aqv
 
RE: SDR: Ham Radio of the Future?  
by N8VB on June 4, 2008 Mail this to a friend!
<Thanks for that info Phil. So if understand correctly, the Dynamic Range of the SDR is actually the Dynamic Range of the ADC + the processing gain in the software. Thats why a ADC that has around 100db DR can actually have a DR of 123db. Also, if I understand what I read correctly, there is still a hard limit on the dynamic range, it's just that processing gain improves that limit. My question becomes, does filter size affect the processing gain. In other words, if the ADC+processing gain = 123db dynamic range, and I have say a 125 db signal on the input of the ADC, will changing the filter size to a smaller filter improve the blocking DR on the SDR and perhaps preventing the blocking from occurring, or does it stay the same. I thought it stayed the same, regardless of filter size, and was the point of my previous comment, but perhaps I am wrong about that? If it does change the DR, then that is something I did not know.>

The QS1R SDR, as an example, has a saturation limit of +10 dBm. As long as signals coming into the ADC stay under this limit, going to a narrower filter size improves BDR and SNR. As the +10 dBm limit is exceeded, the SNR degrades gracefully - even at +25 dBm you are still able to receive all but the weakest signals.

Regards,

Phil N8VB
http://www.srl-llc.com
 
SDR: Ham Radio of the Future?  
by KB3MMX on June 4, 2008 Mail this to a friend!
The FT-950 is a cheap radio to use as a comparison!

If you want to really compare SDR to analog why not go heads up against a Flex 5000.....heck or even a SDR reciever kit.

The future is true SDR and will offer ham radio FAR more tunability and preformance than it has ever had in history.

There will still be some analog guys out there no matter what....

At least the technology is advancing for most of us.



73,
Chuck
 
SDR: Ham Radio of the Future?  
by AG5P on June 4, 2008 Mail this to a friend!
There we have it folks a virtual cornucopia of answers that can be summed up with this one statement…….opinions are like a#@holes everyone has one. Walter no longer has this call so dont blame him for this opinion.

AG5P
 
RE: SDR: Ham Radio of the Future?  
by S5M on June 5, 2008 Mail this to a friend!
N8VB: As the +10 dBm limit is exceeded, the SNR degrades gracefully - even at +25 dBm you are still able to receive all but the weakest signals.

Phil, considering your great work on SDR, could you provide any measurements for the above declaration?
ADC overflow data are useless and I wonder how blocking procedes with possible interpolation. SM5BSZ puts hard limitis.

73 de Mario, S56A, N1YU, MSc EE retired

 
RE: SDR: Ham Radio of the Future?  
by W9OY on June 7, 2008 Mail this to a friend!
N8VB

The hardware limit pretty much stays the same. You can add some pre-ADC filtering to spruce things up a little like bandpass filters and pre-amps which will take away some of the wide band offending signals but the limits are pretty much the limits. The way the radio works is you convert to a base band freq at the level of the QSD and send that data to the ADC which sends a stream of quadrature data points on to the computer for further processing. The bandwidth of the signal at this point is the bandwidth of the base band signal aka 48khz or 192khz or whatever. The way I think of it is like slicing up a cucumber into very thin slices and then recompiling all the slices into something that looks like the cucumber. Its discrete slices, but the original "data" is retained. The entire cucumber is like the 48khz bandwidth, and in the computer you select out some small portion of the cucumber and build a filter around it and run it through a processor to demodulate it and convert it back to something suitable for your listening pleasure

Once the signal is in the computer is where the signal processing occurs and this is where the filtering and demodulation is added before reconverting the signal back to something suitable for your ears. The ADC fails all at once. It is not like an analogue situation where distortion starts and then builds. Once the last bit is violated the signal fails, but until the last bit is violated there is no signal degradation. Conceptually it needs to be thought of in a different analogy than how you think of a linear device.

This over simplifies but it gets the point across

73 W9OY
 
Ham Radio of the Future?  
by WA2JJH on June 7, 2008 Mail this to a friend!
W9OY, nice analogy! The CAT SCANNER, a staple at most hospitals, uses an algorythm called......"THE CENTRAL SLICE THEOREM"
THE NYQUEST LIMIT also is very applicable too.

Bottom line is.............

I will purchase the ""softrock"" kit and make my own conclusions.
 
RE: SDR: Ham Radio of the Future?  
by N8VB on June 8, 2008 Mail this to a friend!
W9OY:

W9OY wrote:
<N8VB
The hardware limit pretty much stays the same. You can add some pre-ADC filtering to spruce things up a little like bandpass filters and pre-amps which will take away some of the wide band offending signals but the limits are pretty much the limits. The way the radio works is you convert to a base band freq at the level of the QSD and send that data to the ADC which sends a stream of quadrature data points on to the computer for further processing. The bandwidth of the signal at this point is the bandwidth of the base band signal aka 48khz or 192khz or whatever. The way I think of it is like slicing up a cucumber into very thin slices and then recompiling all the slices into something that looks like the cucumber. Its discrete slices, but the original "data" is retained. The entire cucumber is like the 48khz bandwidth, and in the computer you select out some small portion of the cucumber and build a filter around it and run it through a processor to demodulate it and convert it back to something suitable for your listening pleasure>

I was not talking about a QSD based system. The QSD is pretty much dead for future SDRs. It will be relegated to cheap softrock, low power, and hobbist type projects. I predict that Flex will also drop the QSD in favor of direct sampling for its future products.

W9OY wrote:
<Once the signal is in the computer is where the signal processing occurs and this is where the filtering and demodulation is added before reconverting the signal back to something suitable for your ears. The ADC fails all at once. It is not like an analogue situation where distortion starts and then builds. Once the last bit is violated the signal fails, but until the last bit is violated there is no signal degradation. Conceptually it needs to be thought of in a different analogy than how you think of a linear device.
This over simplifies but it gets the point across
73 W9OY>

Maybe the ADC in your sound card fails all at once, but I was not talking about sound cards (nor old fashioned QSD based systems like Flex uses now). The QS1R is a direct sampling RX. The LTC2208 also saturates gracefully (values wrap around) so as the input limit is exceeded, the noise floor gradually rises masking weaker signals - signals above the increased noise floor can still be demodulated.

73 Phil N8VB
Software Radio Laboratory LLC
Columbus, Ohio
http://www.srl-llc.com
 
RE: SDR: Ham Radio of the Future?  
by WA2JJH on June 9, 2008 Mail this to a friend!
N8VB-NICE DESIGN!!!!! Just checked out ur site
 
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