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Panadapter Signal During Transmit

Ed, K0KCEd, K0KC Member ✭✭
Is the signal displayed by the panadapter during transmit in the Flex 6700 a sample of the signal that goes out over the air or is it a sample at some point prior to the final amplifier transistors? Ed, K0KC

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Answers

  • Dale KB5VEDale KB5VE Member ✭✭
    edited January 2017
    Ed I have asked this question twice in the past and have not got a answer. If you notice the skirts are down about -125dbm.
  • Ed, K0KCEd, K0KC Member ✭✭
    edited September 2017
    Although the signal may look clean on the panadapter, I would like some assurance that it it looks this good when it reaches the antenna. I do not have the equipment to properly monitor it at that point. Ed, K0KC
  • Ed, K0KCEd, K0KC Member ✭✭
    edited September 2017
    Steve, Thanks for the info...I, for one, like the current solution! Ed, K0KC
  • George KF2TGeorge KF2T Member ✭✭✭
    edited February 2019
    Is there a way to drop the RX sensitivity during transmit to clean up the display and maybe correlate the peaks to the top of the panadapter?
  • Mike - N1MDMike - N1MD Member ✭✭
    edited April 28
    Steve, Thanks so much for this insight and explanation. This has helped me understand what I am looking at during transmit and has increased my enjoyment of this amazing radio. Personally, I am always impressed when you write to us collectively. Your explanations are concise, readable and with a minimum of jargon. You get to the point and answer the question without a tap dance. I my world you would be "a great doc". Mike
  • Ken - NM9PKen - NM9P Member ✭✭
    edited December 2016
    I like it showing what is actually being transmitted, even with the internally generated spurs outside the TX passband. The next step would be to unmute the receiver and direct a reduced level audio to the monitor so we could actually hear what it sounds like in our own receiver. (I assume this is possible even on the 6500?) Or would that cause too many problems, such as messing up the very hard-earned excellent QSK performance on CW? (In which case I would nix the idea.)
  • Dale KB5VEDale KB5VE Member ✭✭
    edited April 2014
    Great response Steve. I asked this same question about a month ago and it was never addressed. Now if I transmit on slice A on3720.000 I will be seeing my recieve when I key the mic and talk correct. And if I go to slice b on a another pan adapter and set it to recieve 3720.00 I will see the same thing on both panadapters , is that what you are saying? I have been doing this for a while and it appears the second panadapters is a little behind the transmit pan. I like what I see and now as I understand it the spurs on the side of the transmit is actually othe noise on the frequency.
  • philip.theisphilip.theis Member
    edited December 2014
    I agree with George, a little less gain if that is possible.
  • Bob N7ZOBob N7ZO Member ✭✭
    edited February 2017
    Steve,  Good explanation, but isn't there a tap on the output of the PA that was meant for adaptive pre-distortion (in the future)?  Why would that not be a good place to sample the signal for transmission monitoring?
  • K4EARK4EAR Member
    edited April 2014
    I'm all for such an approach! I think the 5000 had this with a 80db pad on the HRFIO board and enabling TX monitor routed padded PA rf to a RX in.
  • K4EARK4EAR Member
    edited April 2014
    My +1 bump for this monitoring ability. Let's make it happen sooner, not later.
  • K4EARK4EAR Member
    edited April 2014
    Trying to monitor actual TX audio in my 5000 has too much delay to follow the 6700.
  • Bob N7ZOBob N7ZO Member ✭✭
    edited December 2016

    One of the things that attracted me to the 6000 series was its precision - mathematically clean modulation, demodulation and filtering.  Counting on leakage to monitor the transmit signal seems so…un-Flexworthy.  :-)



  • Tim VE6SHTim VE6SH Member ✭✭
    edited March 2019
    "Later we found that some mixing of on-air signals and other signals in the receiver result in some visible spurs or other anomalies that are not actually on-air. "

    Is this still the case today? I have some transmit spurs on either side of my passband (in wide mode)which I thought were due to RFI. I gather that is not the case and such spurs are "normal". I am in the process of reducing some RFI when I moved to the 6700 (thanks to Al NN4ZZ for his website)and has assumed I would be able to eliminate the spurs.

    73

    Tim VE6SH
  • DrTeethDrTeeth Member ✭✭
    edited August 2016
    Tim, I think it would be a good idea if someone could produce an annotated screenshot showing the spurs. I would find it handy to know exactly what one looks like so I can tell if what I see is okay. I was bemused the other day when I deliberately over-drove my TX (AGC slamming into the red) as a test to see the panadaptor showing a clean signal.
  • Steve-N5ACSteve-N5AC Community Manager admin
    edited December 2016
    The deal here is this: the ability to see your transmit signal is a nice benefit, but it should not be trusted to tell the "whole story."  Due to some coupling in the radio (which varies by band), you will see things that are not representative of the actual on-air signal.  This display (pan during TX) is good to get an idea for what your signal looks like on the given mode and band and then recognize when something is very different.  In this case (something different), you should then look on a RF monitor (independent, spectrum analyzer, etc) to determine what is really wrong.
  • Tim VE6SHTim VE6SH Member ✭✭
    edited December 2016
    Thanks Steve. That confirms your earlier comment. I had thought this was a by-product of some RFI, but obviously not the case (and yes on closer inspection it only occurs on some bands).

    Thank you for your response!

    73

    Tim VE6SH
    

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