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Author Topic: Protection of RX with RX antenna only Ports  (Read 4062 times)
K9IUQ
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Posts: 1687




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« Reply #15 on: January 09, 2010, 08:30:33 AM »

Bill says "This is truly a serious problem that Flex needs to address."

I agree 100 percent, which is I why I sent inquirys to the Flex reflector AND Flex tech support.I will be very interested in their replies.


Bill says "Yaesu made a very bad reputation by stone-walling the FT-1000 key click problem for ~15 years"

I listen to 160 mtrs pretty regular. Hear both you and W8JI. W8JI has bad key clicks. I use Cw Skimmer and W8JI pretty much wipes out the waterfall with clicks. I have turned the click filter on but it still does not elimanate them completely. I assume he is using his K3. I have never noticed them on your signal. Both of you are 30db over s9 or so here in S.IL.

As you know I have been researching radios for many months. I got MANY private emails from K3 owners that are not happy with this or that. Poor RX audio and RX noise were commented on by many owners. RX spurs also mentioned frequently. Most of these hams will not post on a public forum because the K3 true believers can get pretty nasty. Even Rob Sherwood wrote me privately  a couple of times concerning K3 problems. It said a lot to me when Rob said he had a K3 for a couple of months and declined to buy one, sticking instead with his Icom's.

Since I own neither a K3 or a Flex yet I am not biased. The opinions I have formed came from reading relectors and private email from owners like you. I appreciated the comments you gave to me and value them because you are such a respected 160 mtr "Guru".

Stan K9IUQ
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K9IUQ
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Posts: 1687




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« Reply #16 on: January 09, 2010, 08:39:29 AM »

W8JI says: "That's like going to the Ford Mustang forum and asking how Mustangs are. :-)"

Take out Ford Mustang and insert K-3. I have been on the K-3 relectors for many months and it is obvious many drink the Elecraft Kool Aid. Mostly the only honest responses I got on the K-3 were private emails. If you dis the K-3 in public, one will get beat up cuz them K-3ers can get VERY nasty. I actually had one K-3er write me an extremely nasty email telling me to get off the K-3 reflector because my questions were too detrimental to K-3's....

Stan K9IUQ
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K9IUQ
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Posts: 1687




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« Reply #17 on: January 09, 2010, 08:43:03 AM »

W8JI says: "Fair enough, but please mark down and check the frequencies 2.4 up and down, and make sure they are clear! When you send a QRL? on 1827, be sure you check 1824.6 and 29.4 to be sure they are not busy also.  :-)"

NOT fair enough. This is not how I want to operate. If Flex is not addressing the issue, it will be simple. I will not own a Flex. Period.

Stan K9IUQ
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W8JI
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« Reply #18 on: January 09, 2010, 06:35:57 PM »

W8JI says: "That's like going to the Ford Mustang forum and asking how Mustangs are. :-)"

Take out Ford Mustang and insert K-3. I have been on the K-3 relectors for many months and it is obvious many drink the Elecraft Kool Aid. Mostly the only honest responses I got on the K-3 were private emails. If you dis the K-3 in public, one will get beat up cuz them K-3ers can get VERY nasty. I actually had one K-3er write me an extremely nasty email telling me to get off the K-3 reflector because my questions were too detrimental to K-3's....

Stan K9IUQ

I don't know why people are like that, although some people do make mistakes or make a single problem with one radio a universal problem.

I don't know of any perfect radio. They are just like women. :-)

I will say this....I like how my Yaesu FT1000MP MKV's feel and work better than anything else except:

I don't like a virtual radio, I want something to just grab and push buttons. I spend too much time with my computer as it is.

I need stereo diversity with my antennas. Only the K3 does that properly in a radio package. There is no other choice.

I want a cleaner transmitter. Even though I have declicked the MKV's, I'd like them to be better. The K3 is much cleaner (sometimes too clean).

The K3 is better receiving with strong signals on crowded bands like contests.

I'd like the K3 to be inside the FT1000 box and use the knobs and buttons of the FT1000, but it isn't going to happen.

 

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K9IUQ
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Posts: 1687




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« Reply #19 on: January 10, 2010, 04:05:00 AM »

W8JI: "I don't like a virtual radio, I want something to just grab and push buttons. I spend too much time with my computer as it is."

Like it or not it IS coming.

I worked in industry as an electrician/ instrument tech until my retirment in 2001. When I started as a young lad all motor control was mechanical devices/ buttons/relays/stepping switches etc. Instrumentation was standalone device with meters, knobs etc. That all changed with the advent of PLC's and the desktop computer. Now motor control is controled via a computer or PLC, the start and stop buttons are on a computer screen.No control panels, no real buttons just a computer screen and a keyboard or touchscreen or mouse.

Instrumentation has gone the same way. No more stand alone instruments. It is all displayed and controlled on a computer screen somewhere.

SDR is the future of hamradio whether one likes it or not....

Stan K9IUQ
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W8JI
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« Reply #20 on: January 10, 2010, 04:09:54 AM »

W8JI: "I don't like a virtual radio, I want something to just grab and push buttons. I spend too much time with my computer as it is."

Like it or not it IS coming.

I worked in industry as an electrician/ instrument tech until my retirment in 2001. When I started as a young lad all motor control was mechanical devices/ buttons/relays/stepping switches etc. Instrumentation was standalone device with meters, knobs etc. That all changed with the advent of PLC's and the desktop computer. Now motor control is controled via a computer or PLC, the start and stop buttons are on a computer screen.No control panels, no real buttons just a computer screen and a keyboard or touchscreen or mouse.

Instrumentation has gone the same way. No more stand alone instruments. It is all displayed and controlled on a computer screen somewhere.

SDR is the future of hamradio whether one likes it or not....

Stan K9IUQ

It can be SDR if it has a good roofing filter or enough wide-spaced dynamic range, and if it has proper human interface. I have nothing against SDR. :-)
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W4ZV
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« Reply #21 on: January 11, 2010, 07:15:00 AM »

K9IUQ;

> SDR is the future of hamradio whether one likes it or not....

W8JI:

> It can be SDR if it has a good roofing filter or enough wide-spaced dynamic range, and if it has proper human interface. I have nothing against SDR. :-)

In fact most current top-line radios are SDRs, beginning with the Ten-Tec Pegasus and Kachina over 10 years ago.  This includes the FT-2000/5000/9000, IC-7800/7700/7600, Ten-Tec Orion I/II, Elecraft K3 and some Kenwoods.

SDR simply means "software defined radio" which applies to all of the above since all may be updated with firmware.  SDR does not mean being forced to use a computer interface like Flex, QSDR, Pegasus, etc.

The SDRs winning in the marketplace cleverly hide the computer crap and provide a human interface that's more comfortable for most users.  They're also running on dedicated processors (e.g. ARM) using efficient (and fast) machine language so they're not burdened with Windoze on GP computer chips.  This is a key reason why rigs like the K3 have excellent QSK and Windoze implementations do not.

To answer Stan's original question about RX antenna protection, KD9SV's "Front End Saver" is a commercial unit for $80 that is used by many.  

http://www.radiobooks.com/products/fes.htm

If you want to roll your own, here's a good schematic from K9AY:

http://www.aytechnologies.com/TechData/RIP-1.pdf

I've never used any of these with any of the rigs I've had (TS-930S, FT-1000MP, Orion or K3) because I'm careful to locate my RX antennas a reasonable distance from my TX antennas, and the above rigs have a reasonable amount of protection already built-in.

73,  Bill  W4ZV
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W4ZV
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« Reply #22 on: January 11, 2010, 07:27:58 AM »

I was wrong about the ARM processor...it's a TI.  Here's more info from the DSP designer KK7P:

I've had several private questions about the DSP.  I'll combine the
information and make it public here :-)

The K3's DSP is a Texas Instruments TMS320VC33-150 embedded DSP, not a
PC CPU from Intel or AMD or VIA.  There is one DSP chip per receiver;
the subreceiver option includes a PC board assembly incorporating the
second DSP.

The TMS320VC33 is a 32-bit, floating point processor that we chose for
its performance, low power consumption, and the fact it has been in the
marketplace long enough to have a completely functional silicon along
with a development tool suite that is stable.

The DSP firmware is written in assembly language, and is original.  It
does not borrow from any GPL'ed sources or use any commercial "function"
libraries. It does not run on a formal operating system.

Much of the DSP peripheral support hardware is contained in a
flash-based programmable logic device.  This enables us to connect a
very high performance 24-bit A/D converter for the receiver IF, two more
channels of greater-than 16-bit A/D for microphone and PC input, and
several more channels of less-than 16-bit A/D for more mundane things
like forward and reflected power, upstream signal level detection, and
so forth.  It also connects six D/A channels, lets the DSP check some
digital I/O lines (e.g., to support true FSK generation) -- and to
communicate with the control processor!

Oh, and it enables the DSP's Flash memory to be programmed by the user :-)

73,

Lyle KK7P
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K9IUQ
Member

Posts: 1687




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« Reply #23 on: January 11, 2010, 09:12:05 AM »

W4ZV, Bill opines: In fact most current top-line radios are SDRs, beginning with the Ten-Tec Pegasus and Kachina over 10 years ago. This includes the FT-2000/5000/9000, IC-7800/7700/7600, Ten-Tec Orion I/II, Elecraft K3 and some Kenwoods.

SDR simply means "software defined radio" which applies to all of the above since all may be updated with firmware. SDR does not mean being forced to use a computer interface like Flex, QSDR, Pegasus, etc.

.....................................................

Here is the definition of SDR from Wikipedia:

"A Software-Defined Radio system, or SDR, is a radio communication system where components that have typically been implemented in hardware (e.g. mixers, filters, amplifiers, modulators/demodulators, detectors, etc.) are instead implemented using software on a personal computer or embedded computing devices."

Sorry Bill but Your K-3 does not meet this definition of SDR. Your K-3 has filters right? Ex$$pensive filters. Does the K3 have an embedded commputing device?  Just because a radio has an updateable firmware chip does not make it a SDR. Having a DSP chip does not make a radio a SDR....

The Flex radios are SDR, NO dispute about that.

Maybe you could stretch it a bit(actually a lot) and call the K-3 a hybrid but SDR it is not..

Stan K9IUQ
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K9IUQ
Member

Posts: 1687




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« Reply #24 on: January 11, 2010, 09:22:35 AM »

W4ZV says:"To answer Stan's original question about RX antenna protection, KD9SV's "Front End Saver" is a commercial unit for $80 that is used by many.'
http://www.radiobooks.com/products/fes.htm

Bill,
This may be exactly what I am looking for. I did not know about this device.

My RX antenna will be within 200 ft of my xmit antenna. I do not think that is far enough away to protect even a stout frontend since I run legal limit at times.....

THANKS
Stan K9IUQ
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W4ZV
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« Reply #25 on: January 11, 2010, 10:13:46 AM »

"A Software-Defined Radio system, or SDR, is a radio communication system where components that have typically been implemented in hardware (e.g. mixers, filters, amplifiers, modulators/demodulators, detectors, etc.) are instead implemented using software on a personal computer or embedded computing devices."

> Sorry Bill but Your K-3 does not meet this definition of SDR. Your K-3 has filters right? Ex$$pensive filters.

Yes it has filters...so does the Flex, so does a Perseus.  In fact every DSP receiver must have anti-aliasing filters ahead of the ADC.  The Flex uses filters and a local oscillator to convert signals to 9 MHz.

> Does the K3 have an embedded commputing device? Just because a radio has an updateable firmware chip does not make it a SDR. Having a DSP chip does not make a radio a SDR....

Yes, it has both a MCU and DSP (two if you get a KRX3).  The MCU is the controller which is basically the system traffic cop.  Both are firmware programmable.  Just because the storage media is internal Flash rather than a hard drive in a computer makes no difference.  In fact solid state drives are now replacing hard drives in some computers.

> The Flex radios are SDR, NO dispute about that.

Yes they are but they're not actually direct conversion SDRs, like Perseus or the QS1R, and even those must have an analog anti-aliasing filter ahead of the ADC.

> Maybe you could stretch it a bit(actually a lot) and call the K-3 a hybrid but SDR it is not...

I guess we'll just have to disagree.  Yes the K3 is a hybrid but so is the Flex.  See below from ARRL's review of the F5k:

In an SDR, analog RF signals are converted
to a digital bit stream, and everything
happens at that level using digital signal
processing (DSP) techniques before conversion
back to analog. As FlexRadio explains,
its SDR is “essentially a direct-conversion
receiver, but the mixing of the LO [local oscillator]
to create a 9 kHz IF makes it appear
a lot like a dual-conversion receiver.”  

A true direct conversion SDR (e.g. Perseus) samples RF at twice the maximum frequency applied to the radio (e.g. 60 MHz for a 30 MHz radio) but even this still requires an anti-aliasing filter.  That is probably the purest form of SDR.  Both the Flex and K3 are hybrids doing sampling at a lower IF.

It is a MYTH that SDRs don't have analog filters in them.  Icom's President Inoue said something very stupid to that effect several years ago which I'm sure he now regrets.

73,  Bill
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N7IOH
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Posts: 116




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« Reply #26 on: January 21, 2010, 01:56:08 AM »

How about the MFJ-1708 RF Sensing, TR switch.  It works with 12vdc or 110vac and will ground the receive antenna.

http://www.mfjenterprises.com/Product.php?productid=MFJ-1708

Al, n7ioh
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K9MRD
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Posts: 331




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« Reply #27 on: January 21, 2010, 10:10:26 AM »

W4ZV says:"To answer Stan's original question about RX antenna protection, KD9SV's "Front End Saver" is a commercial unit for $80 that is used by many.'
http://www.radiobooks.com/products/fes.htm

Stan,

I use the Front End Saver on 80 meter CW where I have a receiving flag antenna. It works fine, but the relay chatter drives me nuts using QSK so I don't operate that mode on 80.  I added an on/off switch to the Front End Saver so that it would not bother me when I don't use the receiving antenna. My rig grounds/disconnects the RX antenna port when it is  not selected. If you work QSK CW or chase DX you may find a non-relay solution will make you happier. Smiley

Wayne
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W8JI
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« Reply #28 on: January 22, 2010, 05:07:13 AM »

How about the MFJ-1708 RF Sensing, TR switch.  It works with 12vdc or 110vac and will ground the receive antenna.

http://www.mfjenterprises.com/Product.php?productid=MFJ-1708

Al, n7ioh

Anything that switches by RF will switch much too slow. Some things that switch by manual keying lines (line the amp relay line) will even switch too slow.

The DX Engineering TR switch has diode limiters that would protect for a slow relay and a relay, but does not have RF sensing. It would however need to be connected "backwards" for this application. It does not have RF sensing for a good reason.  It is electrically impossible to have it disconnect the receiver before RF actually hits.

I'm not sure about other switches, but a receiver needs more than one level of protection unless switching is sequenced properly, which means the protection is enabled at least 2-5 mS before RF hits.

Tom



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