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Author Topic: Choosing a rig and Sherwood's list  (Read 4707 times)

W1VT

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Re: Choosing a rig and Sherwood's list
« Reply #75 on: May 28, 2021, 03:14:02 PM »

You may want to look for rigs that are supported online by other users.

Nobody can make all the mistakes necessary to totally understand a modern radio, but a user base of five thousand enthusiastic hams can come pretty close.  Some forums have searchable databases so the smart ham doesn't have to ask a question that has been asked dozens of times.

Zak W1VT

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K4FMH

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Re: Choosing a rig and Sherwood's list
« Reply #76 on: July 21, 2021, 05:39:57 AM »

You may want to look for rigs that are supported online by other users.

Nobody can make all the mistakes necessary to totally understand a modern radio, but a user base of five thousand enthusiastic hams can come pretty close.  Some forums have searchable databases so the smart ham doesn't have to ask a question that has been asked dozens of times.

Zak W1VT

Hi Zak,

Your thought here is a key part of my study, putting together Rob’s pioneering work on comprehensive Rx performance, collective consumer satisfaction, and price (including bang fir the buck). My latest talk on it to the Sutton & Cheam Club in London is here: https://youtu.be/EspoubeuE_k?t=1

73,

Frank
K4FMH
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W9AC

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Re: Choosing a rig and Sherwood's list
« Reply #77 on: July 21, 2021, 06:31:46 AM »

>"Thus the “holy grail” of wanting a 100 dB radio is only a CW [Contesting] pile-up issue."

That quote from Rob was written in 2014, before nearly everyone's bizarre obsession with FT8.  FT4/FT8 carriers with extremely narrow spacing are filled within a 3-4 kHz passband in much the same manner as a CW pile-up.

Paul, W9AC 
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K6BRN

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Re: Choosing a rig and Sherwood's list
« Reply #78 on: July 22, 2021, 09:57:13 AM »

Hi Paul:

This is an old thread, BTW.

I operate mostly FT8 (and JT-9 and JT-65 before that, and AMTO, RTTY and CW before that, etc.)

FT8 is a lot different from CW in that the digital baseband filtering and correlation algorithms inherent in WSJT-X does a much, much better job than MY ear does in picking out even overlapping signals below the noise floor.  A little more than a year ago, WSJT-X, with little fanfare, was significantly improved to tolerate overload/distortion from strong adjacent signals.

Overload occurs not only in the receiver front end but in the ADC back end before processing by WSJT-X.  And although I've worked with DSP/spread spectrum systems for years, I'm very impressed with how Joe Taylor and his team handled this problem.  While I have some speculation on how it was done, it works so well I know that I don't know or understand the full extent of the algorithm tweaks.  So I won't speculate.

Regardless, I've found that the latest WSJT-X performs similarly on Yaesu FT-991, FTDX-3000, Icom IC-7300 and FLEX-6600 radios.  This doe NOT mean that there are not (to me) relatively minor differences.  But all of them have had very little problem decoding signals - even overlapping ones (I use multi-pass decoding) on todays VERY crowded FT-8 band segments.

It's pretty much like a CW contest pile-up every day, particularly on 20M and 40M.

So in my real-world use, significant (but not extreme) differences in dynamic range between radio to radio in the 3 KHz or so FT-8 segments does not seem to make too much of a difference in decode performance.  And I live in a very ham-dense neighborhood in L.A.

I've NO DOUBT AT ALL if the radio's dynamic range was VERY poor and its overload distortion particularly obnoxious, the radio would make a BIG difference.  But between the ones I've mentioned, not so much.

What has YOUR experience been?

Best Regards,

Brian - K6BRN
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N8FVJ

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Re: Choosing a rig and Sherwood's list
« Reply #79 on: August 08, 2021, 09:23:15 AM »

Interesting subject. Ones quality of their hearing is an issue as some radios are more clear sounding than others. There is no measurement for that. First an external speaker will change the quality from the 2.5 to 3" internal speakers of transceivers. But, some sound better than others on external speakers too. And, DSP quality is another factor. I find the Kenwood TS-830S to have such high quality DSP is not needed with my poor hearing. The TS-950SD is another with very clear audio. My hearing is basically full range, but lost the ability to remove background noise.
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VE3WGO

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Re: Choosing a rig and Sherwood's list
« Reply #80 on: August 12, 2021, 01:19:37 PM »

I agree with N8FVj... our own hearing plays a large role in the performance of the end-to-end receiving chain.

And just like the different opinions on the other recent thread about DSP Noise Reduction in this Station Building forum, we will each have our individual opinions of how well a radio sounds or performs in our particular environment.

I for example have found in my own operating habits and location, that wideband intermod dynamic range (ie interference immunity) and noise reduction are my two most important aspects of receiver performance.

73, Ed
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KA4WJA

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Re: Choosing a rig and Sherwood's list
« Reply #81 on: October 13, 2021, 03:42:58 PM »

Frank, Zak, Jim, Ed, et al,

1)  Rig choice for experienced radio ops is rather easy....and, except for those looking for a serious CW contest rig (particularly for 160m CW contesting), the ranking on the list is rather moot.

This is not only my opinion and of many, many other experienced ops....but, surprisingly to some, is also Rob Sherwood's opinion! (read what he writes and listen to what he says, don't just look at a list)

But, these days, (in my opinion), it seems that many newer / less experienced hams (or those new to HF / less experienced in HF comms), seem drawn to the simplicity of "a list", rather than understanding the nitty-gritty of what is needed / what works best in various environs and applications....so...

So, here we are....with this discussion.

 

2)  Yes, joining a particular model / brand "user group" (or at least reading some postings of long-time users of whatever model rig you're considering, especially those of experienced ops), is a GREAT idea!!  (and, I've done this....and found some good info and some effective "mods"...but...)

But, please remember that not all problems/issues you'll read of are really problems with the rig, as many are operator-caused errors....and, some/many "mods" / "updates" cause more issues than they solve.

{One recent example...we've all heard/read of many IC-7300 owners lament the ease-of-overload, when the operator simply needed to apply some attenuation or reduce the gain (just like they're are supposed to do, whether using a super-het receiver, or a direct-sampling SDR), but here with an inexpensive direct-sampling SDR, this becomes more critical for the operator to actually know how-to use the radio.

And, another case-in-point....my beloved Drake TR-7 has a nice clean transmitter w/o any ALC issues, etc. (as many/most modern rigs do), as the ALC is only used as a a power limiting circuit when tx gain /power is adjusted to maximum, but also has a smooth action (no ALC pumping) with a rather long time constant....this allows ALC action to not adversely effect transmit IMD (hence no "buck-shot")....and, you can even run the rig at whatever power level you desire, and adjust so you do not use any ALC at all :) ...but, a case-in-point, on the negative side of a possible mod....there is a mod online, where some unknowing ham recommends changing a cap or two, shortening the ALC time constant significantly (making it about 30% - 40% of what it is from the factory), in order to give the audio "more punch....like a 'poor-man's' speech processor"....so, if the unsuspecting / ignorant ham takes this advice, he ruins (or at least seriously impacts) the great transmit purity of a great rig, just so his audio is "punchier". :(   [another reason to be weary of buying a "modified rig"]

Now, a case-in-point, on the positive side with the TR-7....there is a simple mod (adding one small wire jumper to the "mode switch" wafer) allowing easy-peasy front panel power output adjustment on all modes (SSB, RTTY, as well as CW and AM), using the factory front panel "Carrier" level control (which originally only adjusted output power in CW and AM modes). :)

So...so, you need to remember that no matter what info you get from online user groups, etc....you really need to understand how radios work, what their spec's mean, and what/how (and if) you should do any mods, as well as understand what these "users" are talking about / if they actually know what they are talking about....etc.!!}




3)   As for what rig sounds better to our own ears? 
Well, yes this is an important point!

And, this is mentioned quite often here, as well as mentioned often by Rob Sherwood himself!   (A rig that is fatiguing to listen to, is not one to buy!)

And, since this is such an important criteria, Rob Sherwood mentions it all the time in his presentations (as well as, for more than 15 - 20 years, repeatedly mentioning the importance of our TRANSMITTERS' spectral purity / IMD, as the limiting factor of our RECEIVERS)....however for some reason many hams simply look at "a list".  :(

And, contrary to what some may think, there are specs (and features) available that can be of some help to those looking for a "better sounding" radio, especially those with hearing issues.  Some manufacturers and some product reviews do show these improved specs (using more normal volume levels for a THD spec, rather than their max audio output....anyone ever needed to turn up their HF rigs AF Gain / Volume higher than halfway?), as well as receive audio freq passband, etc.

Of course, there are also some rigs that have receive audio equalizers, and/or bass-midrange-treble adjustments.

So, have a look at some of Rob's (and Adam's) reviews of various rigs....as well as look at the ARRL product reviews....and, even look at the manufacturer's specs.

Doing all of these, you should be able to find a radio that better suits your needs/desires, and possibly even find one that "sounds good" before you actually get a chance to "play with it".  :)

Of course, headphones do help many, a lot more than some think.  :)  And, with this particular issue, where a rig's audio output isn't as clean or distortion-free as we desire, many times using headphones (usually bypassing the rig's audio amp) can make a world of difference!



73,

John,  KA4WJA


P.S.  Apologies for my use of db instead of dB, and khz rather than kHz, etc....and for using .... as a pause in a continuation of a thought.....and, I suspect a host of other faux pas (whether semantic or engineering), please just accept there are reasons, and me being ignorant is not one of them.  Thanks.

 
« Last Edit: October 13, 2021, 03:49:13 PM by KA4WJA »
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KX2T

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Re: Choosing a rig and Sherwood's list
« Reply #82 on: November 28, 2021, 06:04:26 AM »

John no radio is perfect but Rob's list is one tool to use when looking to buy the best radio you can for your radio dollar plus if you dig into Rob's lists he tests blocking at 100Khz which is really nothing by todays standards cause if you look at any lab numbers of radio's tested by the ARRL labs you will see they tested blocking today at 20Khz, 5Khz and 2Khz and this is were the rubber meets the road in real RX performance as well as dynamic range and phase noise plus RMDR.

If you read the ARRL lab notes on the FTDX101D not only does it have greater than 135Db>blocking spec but they go on to say that that test was with 10Dbm of signal, Yaesu stated to them that that radio would take 27Dbm of signal before blocking. This is what also separates the good radio's from the best and it also did 20 years ago when they came out with the original FT1000MP but by today standards it kind not a chart topper.

Transmit IMD is another area that has always been an Oxy moron cause you have 3rd level, 5th level and so on and it seems that everyone's trying to look at the 3rd level yet they don't look past this number to much but if those numbers don't increase its a wash and a dirty little transmitter. The 50V mosfet finals is another joke and Yaesu for years has prostituted that those designs would be best for cleaner IMD run in class A mode yet they have removed the class A mode from there 200w FTDX101MP and brought into play another circuit called AMC. Its still a mystery on the exact roll this AMC plays but it has tamed the flaming Yaesu's ALC issue they had in the past with rigs like the 9000,5000,3000,1200 and the 2000. All these radio's were designed when Motorola owned the company but the old FT1000MP,MK5 and Field were mostly Yaesu Musen designs from Japan so if you catch my drift getting taken over by a big Corporate Giant can suck allot of wind.

The newer radio's like the FTDX101D/MP and the Ten are designs from Japan, they may not have a GUI like a Flex or an Anan but the RX sections and the TX sections are not bad but as you can tell not many hams READ THE FRIGGING MANUAL cause they set the AMC plus very control all the way to the right plus pin there ALC scale.

This brings me back to the IC7300 along with the overload indicator and the use of an RF gain control in which most buyers really do not understand the real use of RF gain but you take a poll of some seasoned op's who have been in this hobby for 40 to 60 years were they know dam well how and why to use this control an all of a sudden the overload goes away. First off Icom radio's have always had way too much gain in the front end, without a pre amp engaged there around 130Db +- a few without pre amps engaged so to put that into perspective most radio except for Kenwoods are around 122Db+- so off the bat there more sensitive then they need to be in the real world, just take a look at your TR7 which had no pre amp in its front end and really didn't need to. When I owned a 7300 I use to either use the RF gain or on the low bands the 20Db pad cause I could tell it had way too much gain, I only used pre amp 1 on 6 or maybe 10 meters but never needed it on any band lower.

My own experiences I will not bore anyone on 50 years of different rigs but since 2009 I have owned 590S,K3,FTDX3000,IC7300,IC7610,FTDX10 and these days the FTDX101D, they have all performed very well but in the heat of a battle like contesting the radio's like the 10 and which I didn't expect but the RX section even more impressed me was the 101D over the 10 this really surprised me cause the lab numbers were close on these two yet the ability of the 101D not to have any blocking issues really did it for me.

I don't have an engineering degree, I have been in electronics sales plus involved with selling amateur radio's when I was younger, been involved with audio plus sound reinforcement for about 15 years, been an RF Technician for about 15 years plus been involved with this hobby Dxing for a few years then got into DX contesting for a few decades. Today just another 70 year old fart but have learned an seen allot threw the years but I still RTFM many times before I order a rig and wait for it to be delivered, I find it ALWAYS helps.

BTW, back when the TR7 came out I did buy one, I was working for Harrison radio at the time and Drake was the ONLY Amateur radio company that offered an employed discount on there radio's to retail sales people, as you know there is not any real margin in this market. I had to wait six months before Drake worked threw the backorders but it was well worth it. For that time period it was and still is today an very solid RF design plus the RX section was ahead of its time in which it started a trend for up conversion rigs that followed.
Jim
« Last Edit: November 28, 2021, 06:11:42 AM by KX2T »
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5BWAZ

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Re: Choosing a rig and Sherwood's list
« Reply #83 on: December 16, 2021, 10:27:15 AM »

I recently came across this post by Rob Sherwood in the IC-7610 Groups (Ic-7610 vs FTDX 101) and thought it was interesting. All of these SDR's can be improved with firmware so I can see manufacturers pushing each other to always be on the cutting edge of this technology. As a new owner of a 7610, I'm happy to see my radio is hanging with the higher class radios.

<< Rob SherwoodDec 14   #24756
The FTdx-101D measured better than the IC-7610 on one measurement only, dynamic range because it has a roofing filter.  My three 7610s have never been close to overloading from a local signal let alone a skip signal.

I spent the last two contest weekends (ARRL 160 and 10 meters) doing A/B comparisons between the 7610 and a K4D.  Both are direct sampling and by definition no roofing filters.  The 7610 won hands down on CW and SSB.  Thank goodness modern radios are firmware upgradable for feature improvements and bug fixes. The latest update to the 7610 (and other Icom transceivers) was the new scroll feature. This was a massive improvement for a contester the way the waterfall no longer smears / skews off at an angle when tuning.

Over time the K4 will likely improve, but the last two weekends were an eye opener from a contest operating standpoint.  I never got to use an FTdx-101D in a contest, but I did run the FTdx10 during January’s CQWW 160m CW contest. Lab wise the FTdx10 is only a little below the 101D, but operationally I prefer using a similarly priced IC-7300.

Rob, NC0B >>
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KX2T

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Re: Choosing a rig and Sherwood's list
« Reply #84 on: December 19, 2021, 09:22:20 AM »

Rob's comments are all well and good but like in real estate location location location so when your very effective station is located in Bolder Colorado there is a big difference between being there and having the same like station somewhere on the east coast plus place that station near water on the east coast and you have a way different type of circumstances. This is were that 20 to 30db of blocking makes the subtle differences and switching from the 7610 in which I owned for almost 3 years and now own the FTDX101D has shown me the differences. I was swayed by the sexy seductive display on the Icom, even liked the HDSDR software Icom came up with that gave me Flex like GUI but in the end I went for all out RX performance and the Yaesu delivers on all counts.
I also prefer two sets of controls for each RX section and the easy flexibility in switching between the two when you are multi tasking between 75m and 40 at night or during contesting its far easier, to get that with Icom you gotta buy the 7851, that's not happening cause its way above my pay grade.
Yaesu started something with the superhet/SDR platform which only time will tell what the K4HD will do but its clear that the K4 has come to late to the market, it is not being takin as the Radio to have cause Icom has clearly taken the HF SDR rig with knobs place and Yaesu was first in our radio market with the Superhet/SDR platform. What a great time to have radio's of this caliber to buy!
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KA4WJA

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General History of Amateur HF Receivers, over the past 50 some years
« Reply #85 on: July 22, 2022, 08:57:09 AM »

Hello to all,
With the topic of "rig choice", and the recent discussions comparing various new rigs (and some confusion over some of these rigs' architecture), I thought maybe some clarifying info and a bit of history would be helpful?   

Frank, Zak, Jim, Ed, et al,
1)  Rig choice for experienced radio ops is rather easy....and, except for those looking for a serious CW contest rig (particularly for 160m CW contesting), the ranking on the list is rather moot.

This is not only my opinion and of many, many other experienced ops....but, surprisingly to some, is also Rob Sherwood's opinion! (read what he writes and listen to what he says, don't just look at a list)

But, these days, (in my opinion), it seems that many newer / less experienced hams (or those new to HF / less experienced in HF comms), seem drawn to the simplicity of "a list", rather than understanding the nitty-gritty of what is needed / what works best in various environs and applications....so...

So, here we are....with this discussion
.

So....

1)  While I'm known here-abouts for concentrating on "the other half of our transceivers", you know ---- the transmitters!  I've seen a bit of confusion and/or misused terms in reference to our modern HF receivers.

And, while I've written here in this thread...in some detail:

https://www.eham.net/community/smf/index.php/topic,128776.msg1194749.html#msg1194749

https://www.eham.net/community/smf/index.php/topic,128776.msg1195427.html#msg1195427


https://www.eham.net/community/smf/index.php/topic,128776.msg1221132.html#msg1221132

https://www.eham.net/community/smf/index.php/topic,128776.msg1224671.html#msg1224671

https://www.eham.net/community/smf/index.php/topic,128776.msg1227431.html#msg1227431

https://www.eham.net/community/smf/index.php/topic,128776.msg1227433.html#msg1227433

....written in some detail, and included quotes from Rob Sherwood, etc., regarding various criteria for transceiver choices, as well as many specific receiver specs/numbers and their meanings/relevance, etc.

But, I still see some of my fellow hams (AND the marketing teams of some radio manufacturers!) that are mixing various terms and/or misunderstanding some things...SDR, DSP, super-het, phase-noise, "roofing filters", etc., etc...

So, I thought maybe a brief bit of history and a quick look at our HF receiver progressions over the past 50 some years, might be helpful to some of my fellow hams?  (or, it might not?  heck, some cynics might even wonder "why is he bothering?"....but in any case, I'll try to be brief and just talk in generalizations so as to not tick-off anyone...)


2)  So, here ya' go...

The unfortunate facts are that today's local RFI environs (and today's transmit IMD / splatter of our SSB transmitters on the phone bands) eliminate most hams' ability to even come close to using all the capabilities of most of our receivers (whether good old venerable classics, or modern 21st Century rigs)...

But, many still desire to "buy the best" or at least "buy what works best for them, at the price they can afford".....and, unfortunately many are still looking at "the list", thinking this is what will determine "the best", rather than actually reading what Rob Sherwood (and others) actually say/recommend, let alone learn about these criteria and make their own decisions....so...here's some history / info that might provide some additional clarity...

A case-in-point....modern Direct-sampling SDR's might be great, but they ain't perfect....i.e. super-hets, properly designed, still rule! :)


    Have a look down the tunnel of history with me for a moment....(don't worry, I'm only going back to the late 60's, 'cuz this is as far back as I have personal experience with / knowledge of...and, forgive me if, for ease of explaining and clarity, I generalize some things here!)

Of course, there are some "outliers" such as some TenTec Omni's still being "down-conversion" radios, when most of the rest of the market having moved to VHF-first-IF's (i.e. "up-conversion" radios), here is a general outline of our HF receivers' progression over the past 50 some years...


a ---- Back in the days I started in radio comms (late 60's / early 70's), we went from single-conversion super-hets to double-conversions super-hets (and some triple-conv super-hets) .....these all had HF first IF's, with some of the early ones having simple LC first-IF filters and/or just "pre-selectors", the good ones (and later ones) had decent first-IF selectivity (or were modified to have decent first-IF selectivity), with first-IF crystal filters (what many hams, oddly even Rob himself, now call "roofing" filters?), or had options to add first-IF filters....and, some even had provisions for crystal filters in both first and second IF's...

These are what we now refer to as "down-conversion radios"...

{there were no "phase-noise" issues, as these were not PLL- synthesized radios}


b ---- Then, in order to provide "general coverage receivers", into our HF rigs, and/or even incorporate many HF transmit bands, across the 1.5mhz - 30mhz range, without gaps nor image-rejection issues, then we got "up-conversion" radios....those with VHF IF frequencies....originally these had low-VHF IF's in the 40mhz - 48mhz range...[the Drake TR-7 was the first of this design....and, still to this day holds-its-own, even in competition with modern 21st Century rigs, 45 years newer in design.]

These are what we call "up-conversion" radios....but, they were still conventional super-hets....and, later "up-conversion" radios had first IF's in the 64mhz to 75mhz range...

{most of these radios used PLL-synthesizers / VCO's...and while some were quite good....a few were very bad --- like the old Yaesu FT-ONE, and lest we forget the Collins KWM-380 is one of the worst in this regard....it's really got to burn those "Collins guys" when they find out their '380's RMDR is beat by 20 - 25db by the likes of a bone-stock IC-735, or the older TS-830, etc.}


c ----  Then, we got DSP....Digital Signal Processing....which at first was done at AF / Audio stage of the radio....and, some worked "okay" but providing minimal "improvement" in our receivers....(and some weren't even worth turning on)....most were simply additions into existing designs...and, as many more up-conversion radios were made, some of the receiver functions (noise blankers, etc.) were migrated to DSP-implementation...


d ----  Shortly followed by IF-DSP's....which at first were done at a very low final IF freq (some at an IF freq of 12khz, or so), and while this was supposed to be an improvement over Audio-DSP (and some were), some allowing the AGC loop to be run thru this low-IF / DSP, but in some rigs the overall implementation wasn't great (not trying to be overly-critical here, it's just that the technology wasn't quite there yet, at amateur-radio price-points)....but, some did function well and provide some rather steep-skirt IF filtering, without serious ringing, etc...

As time went on the DSP algorithms improved....as did the hardware (the DSP processors, etc.)...so, we had higher-frequency DSP-IF's and better AGC controls, etc., as well as better DSP implementation over all...and, things were getting better....well, sort-of...

We also had noise blanking being done in DSP in many radios now, which if done correctly could've been a good thing ---- but that didn't happen....as, the DSP just wasn't good enough yet, and about this time we also the first narrow VHF First-IF filters appear (and, they took on a new moniker: "roofing filters"), and some were pretty crappy, which made noise blanking difficult (as the poor narrow first-IF filters significantly changed the noise shape, thereby making blanking of impulse noise pretty difficult to do.....note that this still holds true today, and it's only through better noise-blanking algorithms that any modern radio with a narrow first-IF filter has a functioning noise blanker at all.)

Please take note here, excellent noise blanking and narrow, step-skirt, first-IF filters are counter-intuitive....perfecting the latter, all but eliminates the perfection of the other!   Hence, the 9khz wide, smooth 4-pole crystal filter in the 48mhz first-IF of the TR-7 is one of the reasons its optional noise blanker works so well....(fyi, the 7-NB noise blanker for the TR-7, was a ~ $75 option in 1977 dollars = ~ $370 in today's dollars....for just the noise blanker!)  Still 45 years later, one of the best noise blankers in any HF radio, ever!   Sorry about the digression...

So, now we had manufacturers putting narrow first-IF filters into their rigs, some were crap --- some were good....but we still had some noisy VCO's (poor phase noise / poor RMDR)...

{together with DSP tech, we had radios now sporting "band scopes" which quickly became not just a toy, but a useful tool for contesters....}


e ---- At this point (10 - 12 years ago), concurrent with the advancements in DSP tech.....Rob Sherwood, et al, had been concerned about the poor oscillator noise (poor phase noise) from many of our radios' VCO's, for quite a while at this point....and, with these many squeaky-wheels pointing this out, many of the manufacturers (all the while working behind-the-scenes on designs of amateur-priced direct-sampling systems) simply changed from old-tech, bargain-basement VCO's to lower-noise oscillators (not super-perfect, but pretty good....although the TS-590S and SG were in 2010-2014 almost as good as today's state-of-the-art rigs)....and, we got some pretty decent "up-conversion" IF-DSP radios!

{and again, band-scopes, etc., had become an almost mandatory feature....and, at some point "waterfall" displays also started to show up....}


f ----  And, again, at about the same time and just after (8 - 12 years ago)....although we had Flex SDR's around for a while at that point, they were "niche" radios and not really a mature technology at amateur-radio price points....but, we had other manufacturers working behind the scenes on Direct-Sampling-SDR type radios.....and, Icom beat 'em all with a reliable, mature-tech, amateur-priced direct-sampling-SDR, the IC-7300!

And, it had "everything" that "everyone" needed....bandscope, waterfall, touchscreen, etc...but, it was also a great little radio, with excellent transmit audio, and in comparison to most modern 21st Century amateur radios a pretty clean transmitter (although, still not as clean as I'd like / not as good as we had 40+ years ago)  BUT...

But, as many found out....direct-sampling-SDR's needed good operators to use 'em, especially in crowded bands / with lots of strong signals....AND...

And, as we also saw the TS-590SG (which is both an "up-conversion" and "down-conversion" super-het) actually worked better in contest environs, crowded bands, noisy locales, etc...

{BTW, around 5 years ago we had the roll-out of FT-8.....which by happenstance was a solution to the many hew hams / those new to HF, that had been suffering with significant receive RFI for the past few years (due to the rise in so much "made-in-China" consumer electronics / switch-mode power supplies / LED-light regulators / etc. / etc....that surrounds so many urban/suburban ham locations)...and, since the radio becomes less of an important factor in FT-8 operations, and since the '7300, in addition to it being a great little radio over all, was also an excellent FT-8 rig with its 100% duty-cycle ability, etc...so, is it any wonder that the '7300 (and direct-sampling SDR's in general) garnered quite a following....}


g ----  And, then we have manufacturers that answered the call of "one-up'ing" the competition (in regards to HF receiver performance AND features!), and it was clear that the "best-of-both-worlds" was a "down-conversion" super-het with IF-DSP (particularly one with low-noise VCO's, and excellent first-IF [roofing] filters, etc.)......along with a direct-sampling-SDR receiver built-in (so, they'd have their band-scopes, waterfalls, etc.), and that brings us to the current (2022) state in amateur HF receiver design / marketing
(a "down-conversion" super-het with IF-DSP, with low-noise VCO's, and excellent/narrow first-IF [roofing] filters....hmmm, what's that old saying, "everything old is new again!"....sort makes me smile that we're coming full-circle now! :) just adding some new-tech abilities to old-tech designs/architecture! :) )



3)  So, when you're looking at different radios (whether a more conventional "super-het" like the '590SG;  or a full Direct-sampling-SDR like the '7300/7610's;  or a "super-het" with an SDR handling the bandscope, etc., like the '101d/101MP...or especially if you're looking for a bargain and buying an older radio!) and trying to figure them out, and trying to figure out why/how/which receiver is best for your application, now you'll be able to figure out what all these various names / abbreviations / acronyms actually mean, and how they work....all on your own!  :)


I do hope this helps?

73,
John,  KA4WJA
« Last Edit: July 22, 2022, 09:15:56 AM by KA4WJA »
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GRUMPY2021

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Re: Choosing a rig and Sherwood's list
« Reply #86 on: July 22, 2022, 09:29:16 AM »

Fit.    You won't find that on any list.  How well a radio fits you.   I guarantee the top 5 of that list will not fit  me.   Your best bet is forget that silly list and go to a brick and mortar or hamfests and spin some knobs and see what fits you best.   What's that?  No one ever talks about fit?  Because it's too personal a thing and doesn't fit the help support the channel by buying from this link narrative.    Watch out for those channels.
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KD7HNN

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Re: General History of Amateur HF Receivers, over the past 50 some years
« Reply #87 on: July 22, 2022, 09:37:47 AM »

Hello to all,
With the topic of "rig choice", and the recent discussions comparing various new rigs (and some confusion over some of these rigs' architecture), I thought maybe some clarifying info and a bit of history would be helpful?   

Frank, Zak, Jim, Ed, et al,
1)  Rig choice for experienced radio ops is rather easy....and, except for those looking for a serious CW contest rig (particularly for 160m CW contesting), the ranking on the list is rather moot.

This is not only my opinion and of many, many other experienced ops....but, surprisingly to some, is also Rob Sherwood's opinion! (read what he writes and listen to what he says, don't just look at a list)

But, these days, (in my opinion), it seems that many newer / less experienced hams (or those new to HF / less experienced in HF comms), seem drawn to the simplicity of "a list", rather than understanding the nitty-gritty of what is needed / what works best in various environs and applications....so...

So, here we are....with this discussion
.

So....

1)  While I'm known here-abouts for concentrating on "the other half of our transceivers", you know ---- the transmitters!  I've seen a bit of confusion and/or misused terms in reference to our modern HF receivers.

And, while I've written here in this thread...in some detail:

https://www.eham.net/community/smf/index.php/topic,128776.msg1194749.html#msg1194749

https://www.eham.net/community/smf/index.php/topic,128776.msg1195427.html#msg1195427


https://www.eham.net/community/smf/index.php/topic,128776.msg1221132.html#msg1221132

https://www.eham.net/community/smf/index.php/topic,128776.msg1224671.html#msg1224671

https://www.eham.net/community/smf/index.php/topic,128776.msg1227431.html#msg1227431

https://www.eham.net/community/smf/index.php/topic,128776.msg1227433.html#msg1227433

....written in some detail, and included quotes from Rob Sherwood, etc., regarding various criteria for transceiver choices, as well as many specific receiver specs/numbers and their meanings/relevance, etc.

But, I still see some of my fellow hams (AND the marketing teams of some radio manufacturers!) that are mixing various terms and/or misunderstanding some things...SDR, DSP, super-het, phase-noise, "roofing filters", etc., etc...

So, I thought maybe a brief bit of history and a quick look at our HF receiver progressions over the past 50 some years, might be helpful to some of my fellow hams?  (or, it might not?  heck, some cynics might even wonder "why is he bothering?"....but in any case, I'll try to be brief and just talk in generalizations so as to not tick-off anyone...)


2)  So, here ya' go...

The unfortunate facts are that today's local RFI environs (and today's transmit IMD / splatter of our SSB transmitters on the phone bands) eliminate most hams' ability to even come close to using all the capabilities of most of our receivers (whether good old venerable classics, or modern 21st Century rigs)...

But, many still desire to "buy the best" or at least "buy what works best for them, at the price they can afford".....and, unfortunately many are still looking at "the list", thinking this is what will determine "the best", rather than actually reading what Rob Sherwood (and others) actually say/recommend, let alone learn about these criteria and make their own decisions....so...here's some history / info that might provide some additional clarity...

A case-in-point....modern Direct-sampling SDR's might be great, but they ain't perfect....i.e. super-hets, properly designed, still rule! :)


    Have a look down the tunnel of history with me for a moment....(don't worry, I'm only going back to the late 60's, 'cuz this is as far back as I have personal experience with / knowledge of...and, forgive me if, for ease of explaining and clarity, I generalize some things here!)

Of course, there are some "outliers" such as some TenTec Omni's still being "down-conversion" radios, when most of the rest of the market having moved to VHF-first-IF's (i.e. "up-conversion" radios), here is a general outline of our HF receivers' progression over the past 50 some years...


a ---- Back in the days I started in radio comms (late 60's / early 70's), we went from single-conversion super-hets to double-conversions super-hets (and some triple-conv super-hets) .....these all had HF first IF's, with some of the early ones having simple LC first-IF filters and/or just "pre-selectors", the good ones (and later ones) had decent first-IF selectivity (or were modified to have decent first-IF selectivity), with first-IF crystal filters (what many hams, oddly even Rob himself, now call "roofing" filters?), or had options to add first-IF filters....and, some even had provisions for crystal filters in both first and second IF's...

These are what we now refer to as "down-conversion radios"...

{there were no "phase-noise" issues, as these were not PLL- synthesized radios}


b ---- Then, in order to provide "general coverage receivers", into our HF rigs, and/or even incorporate many HF transmit bands, across the 1.5mhz - 30mhz range, without gaps nor image-rejection issues, then we got "up-conversion" radios....those with VHF IF frequencies....originally these had low-VHF IF's in the 40mhz - 48mhz range...[the Drake TR-7 was the first of this design....and, still to this day holds-its-own, even in competition with modern 21st Century rigs, 45 years newer in design.]

These are what we call "up-conversion" radios....but, they were still conventional super-hets....and, later "up-conversion" radios had first IF's in the 64mhz to 75mhz range...

{most of these radios used PLL-synthesizers / VCO's...and while some were quite good....a few were very bad --- like the old Yaesu FT-ONE, and lest we forget the Collins KWM-380 is one of the worst in this regard....it's really got to burn those "Collins guys" when they find out their '380's RMDR is beat by 20 - 25db by the likes of a bone-stock IC-735, or the older TS-830, etc.}


c ----  Then, we got DSP....Digital Signal Processing....which at first was done at AF / Audio stage of the radio....and, some worked "okay" but providing minimal "improvement" in our receivers....(and some weren't even worth turning on)....most were simply additions into existing designs...and, as many more up-conversion radios were made, some of the receiver functions (noise blankers, etc.) were migrated to DSP-implementation...


d ----  Shortly followed by IF-DSP's....which at first were done at a very low final IF freq (some at an IF freq of 12khz, or so), and while this was supposed to be an improvement over Audio-DSP (and some were), some allowing the AGC loop to be run thru this low-IF / DSP, but in some rigs the overall implementation wasn't great (not trying to be overly-critical here, it's just that the technology wasn't quite there yet, at amateur-radio price-points)....but, some did function well and provide some rather steep-skirt IF filtering, without serious ringing, etc...

As time went on the DSP algorithms improved....as did the hardware (the DSP processors, etc.)...so, we had higher-frequency DSP-IF's and better AGC controls, etc., as well as better DSP implementation over all...and, things were getting better....well, sort-of...

We also had noise blanking being done in DSP in many radios now, which if done correctly could've been a good thing ---- but that didn't happen....as, the DSP just wasn't good enough yet, and about this time we also the first narrow VHF First-IF filters appear (and, they took on a new moniker: "roofing filters"), and some were pretty crappy, which made noise blanking difficult (as the poor narrow first-IF filters significantly changed the noise shape, thereby making blanking of impulse noise pretty difficult to do.....note that this still holds true today, and it's only through better noise-blanking algorithms that any modern radio with a narrow first-IF filter has a functioning noise blanker at all.)

Please take note here, excellent noise blanking and narrow, step-skirt, first-IF filters are counter-intuitive....perfecting the latter, all but eliminates the perfection of the other!   Hence, the 9khz wide, smooth 4-pole crystal filter in the 48mhz first-IF of the TR-7 is one of the reasons its optional noise blanker works so well....(fyi, the 7-NB noise blanker for the TR-7, was a ~ $75 option in 1977 dollars = ~ $370 in today's dollars....for just the noise blanker!)  Still 45 years later, one of the best noise blankers in any HF radio, ever!   Sorry about the digression...

So, now we had manufacturers putting narrow first-IF filters into their rigs, some were crap --- some were good....but we still had some noisy VCO's (poor phase noise / poor RMDR)...

{together with DSP tech, we had radios now sporting "band scopes" which quickly became not just a toy, but a useful tool for contesters....}


e ---- At this point (10 - 12 years ago), concurrent with the advancements in DSP tech.....Rob Sherwood, et al, had been concerned about the poor oscillator noise (poor phase noise) from many of our radios' VCO's, for quite a while at this point....and, with these many squeaky-wheels pointing this out, many of the manufacturers (all the while working behind-the-scenes on designs of amateur-priced direct-sampling systems) simply changed from old-tech, bargain-basement VCO's to lower-noise oscillators (not super-perfect, but pretty good....although the TS-590S and SG were in 2010-2014 almost as good as today's state-of-the-art rigs)....and, we got some pretty decent "up-conversion" IF-DSP radios!

{and again, band-scopes, etc., had become an almost mandatory feature....and, at some point "waterfall" displays also started to show up....}


f ----  And, again, at about the same time and just after (8 - 12 years ago)....although we had Flex SDR's around for a while at that point, they were "niche" radios and not really a mature technology at amateur-radio price points....but, we had other manufacturers working behind the scenes on Direct-Sampling-SDR type radios.....and, Icom beat 'em all with a reliable, mature-tech, amateur-priced direct-sampling-SDR, the IC-7300!

And, it had "everything" that "everyone" needed....bandscope, waterfall, touchscreen, etc...but, it was also a great little radio, with excellent transmit audio, and in comparison to most modern 21st Century amateur radios a pretty clean transmitter (although, still not as clean as I'd like / not as good as we had 40+ years ago)  BUT...

But, as many found out....direct-sampling-SDR's needed good operators to use 'em, especially in crowded bands / with lots of strong signals....AND...

And, as we also saw the TS-590SG (which is both an "up-conversion" and "down-conversion" super-het) actually worked better in contest environs, crowded bands, noisy locales, etc...

{BTW, around 5 years ago we had the roll-out of FT-8.....which by happenstance was a solution to the many hew hams / those new to HF, that had been suffering with significant receive RFI for the past few years (due to the rise in so much "made-in-China" consumer electronics / switch-mode power supplies / LED-light regulators / etc. / etc....that surrounds so many urban/suburban ham locations)...and, since the radio becomes less of an important factor in FT-8 operations, and since the '7300, in addition to it being a great little radio over all, was also an excellent FT-8 rig with its 100% duty-cycle ability, etc...so, is it any wonder that the '7300 (and direct-sampling SDR's in general) garnered quite a following....}


g ----  And, then we have manufacturers that answered the call of "one-up'ing" the competition (in regards to HF receiver performance AND features!), and it was clear that the "best-of-both-worlds" was a "down-conversion" super-het with IF-DSP (particularly one with low-noise VCO's, and excellent first-IF [roofing] filters, etc.)......along with a direct-sampling-SDR receiver built-in (so, they'd have their band-scopes, waterfalls, etc.), and that brings us to the current (2022) state in amateur HF receiver design / marketing
(a "down-conversion" super-het with IF-DSP, with low-noise VCO's, and excellent/narrow first-IF [roofing] filters....hmmm, what's that old saying, "everything old is new again!"....sort makes me smile that we're coming full-circle now! :) just adding some new-tech abilities to old-tech designs/architecture! :) )



3)  So, when you're looking at different radios (whether a more conventional "super-het" like the '590SG;  or a full Direct-sampling-SDR like the '7300/7610's;  or a "super-het" with an SDR handling the bandscope, etc., like the '101d/101MP...or especially if you're looking for a bargain and buying an older radio!) and trying to figure them out, and trying to figure out why/how/which receiver is best for your application, now you'll be able to figure out what all these various names / abbreviations / acronyms actually mean, and how they work....all on your own!  :)


I do hope this helps?

73,
John,  KA4WJA


TLDR
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K1VSK

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  • Posts: 1947
Re: Choosing a rig and Sherwood's list
« Reply #88 on: July 22, 2022, 10:09:59 AM »

Any rig in the top 20 of Sherwood's list will outperform the abilities of most antennas and locations. QRM/QRM etc. All these factors will degrade reception more than you gain with a rig's great capabilities.
Quite correct. The Sherwood chart is academic at best and largely meaningless to most hams and certainly to beginners regardless of antenna system.
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KA4WJA

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Re: Choosing a rig and Sherwood's list
« Reply #89 on: July 22, 2022, 10:26:21 AM »

Grumpy, et al,
1)  Thanks for you input....and I agree with you!  :)
And, if you click those links and have a read, you'll see that I'm not the only one!  We have discussed this in detail....have a look see...

Fit.    You won't find that on any list.  How well a radio fits you.   I guarantee the top 5 of that list will not fit  me.   Your best bet is forget that silly list and go to a brick and mortar or hamfests and spin some knobs and see what fits you best.   What's that?  No one ever talks about fit?  Because it's too personal a thing and doesn't fit the help support the channel by buying from this link narrative.    Watch out for those channels.

My reason for adding some more to this thread is directly to help those I see, and hear on-the-air, that might need some clarity in what they are reading / being told. 
 
Grumpy, I do thank you for you input!



2)  Rich, KD7HNN....I freely admit that I had to Google what TLDR meant.  :(

Sorry that this was of no help to you....but, in reality it isn't targeted to longtime hams but rather to those newer hams, especially those new to HF, etc. (I thought that was implied by what I actually wrote....but, since you didn't read it, I guess that didn't register with you....oppss)

In any case, I wish you a nice day!



3)  And, Don, K1SVK....that's really my underlying point (for many years).....and to some it's also ironic that this is Rob Sherwood's point as well....if folks actually read what he writes and/or listen to what he says, he makes it quite clear that he agrees with you!  :)



73,
John,  KA4WJA

P.S.  I just hope that the hams that actually need this info / clarity will actually read it!  hi hi
For the rest of you....thanks for the input. :)
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