Rx audio does not mute during transmit in CW mode.

  • 2
  • Problem
  • Updated 4 months ago
  • (Edited)
In CW mode using v. 2.0.17.96, if I key MOX to transmit, the antenna relay switches & signals in the scope disappear as expected but the underlying radio noise remains unmuted. This happens whether in Break-In mode or not.

Is this normal? It's very distracting.

Please try this with 2.0 yourself. I know of one other 6x00 that does the same thing. I don't remember 1.9.13 operating this way but I don't want to downgrade the software just to verify that version's operation.


My radio is a 6300. I'm using two different client computers, both running Windows 10 and a Maestro. All three do the same thing.

Thanks for any insight on this.
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Bob - W7KWS -

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Posted 2 years ago

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Douglas Maxwell

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This has always been a problem for me Bob and a year later it is still broken in my opinion. it has taken me a while to realise what is going on. Full and semi break-in modes work fine, but when break-in is disabled, delay is set to 0 and PTT is applied, a false receiver hiss is present in headphone audio (try it). I think the Flex is still decoding the rx even although the antenna is connected to the tx. When CW is actually sent, the false hiss is removed and it changes correctly to sidetone. You would think that when break-in is disabled that delay wouldn't have an effect, but the only way to get rid of the false hiss in the audio is to dial in some delay. This isn't a solution as if you change your CW speed setting you have to re-adjust the delay value accordingly, all this even although break-in is disabled!?! The effect is a very choppy sidetone/false hiss audio mess in your headphones during PTT for a 48 hour contest!
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William McCaa, K0RZ

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This problem was introduced with version 1.10.16 and has continued to the present release of version 2.4.9. I been told that it is on the bug list. I find it very frustrating that the 6000 series radios can't perform the basic function of turning off the receiver when the MOX button is activated. Since I work CW, I abandoned using my 6500 on CW and returned to using my Kenwood TS-2000.

I keep expecting a fix since since it showed up in 1.10.16 but am now question the value of keeping the 6000 series radios. I should have kept the 5000.   
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Douglas Maxwell

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I totally understand your frustration, I cannot believe this bug is so low in priority and that more Flex owners aren’t complaining. I am sick of testing new releases only to find this bug repeated in every one. I am also considering returning to my K3 for cw contesting, but the Flex it’s a lot of investment just to be used for the occasional rag chew. Hopefully someone at Flex will realise that not having a fully functioning PTT in cw mode is a major bug and fix it before the contesting community give up on it.
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Bob - W7KWS -

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Douglas, it appears that we can only hope. 73!
(Edited)
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Douglas Maxwell

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I’m fairly sure this is an audio bug and not a PTT signalling bug. I know it’s not a proper solution, but I found that turning the sidetone volume down to a barely audible level helped to limit the annoyance during transmit throughout the UKRDX contest 24hour contest. YMMV.