Hello Robert
It seems to me that your diagnosis of your BC station entering the audio
via the Heil adapter and mic cable is correct and is leading to the
problems you describe.
What happens if you listen on SSB without anything at all plugged into the
mic socket on the rig, put the rig into transmit with and without the
monitor function engaged and then return it to receive? I would guess that
it receives normally. For that test, I would suggest that you use a
separate pair of headphones, ie not the Heil, or even just the internal
speaker.
I have had previous problems with RFI on my transmission using an Orion 2
on 160m. It was not BC station related but simply my own RF entering
through the mic lead. I cured it completely by wrapping the mic lead around
a toroid for as many turns as would fit and close to the mic plug.
I think that the overall answer to your problem is either:
1. A custom made adapter incorporating a toroid as you suggest or
2. Use a different mic with a toroid on the lead if necessary
What happens if you feed the rig into a dummy load ? Is the RFI still there
on SSB with the Heil adapter and/or mic/headset connected ?
73
Barry VK2BJ
On Thu, 23 Dec 2021 at 09:48, Bob, W3IDT <w3idt@comcast.net> wrote:
> Smart persons...
>
> Now that I have the Master Reset issue under control with the
> installation of a fresh battery (and the earlier A9 board capacitor
> upgrades), I still have two, possibly related, transmit audio issues.
>
> One of them I think I know how to fix, for the other I have no clue. And
> I wouldn't dismiss that the issues are related.
>
> 1. Though the first issue may appear to be RFI related, a) this radio
> used to sit next to an Alpha something amp with 1500W going to low
> dipoles very near the shack without any RFI problems, and 2) the radio
> now works fine on CW and FSK/RTTY at full 100w without any RFI problems.
>
> Transmitting in any audio mode, whether SSB/FM/AM via the front panel
> mic input or FT8 via the rear panel input, any transmission above about
> 5 - 10w power kills the receiver. Cycling the main power on/off brings
> the receiver back to life. Sometimes, though, on an immediate power
> cycle the receiver is still dead; waiting a minute or so allows the
> receiver to wake up.
>
> This suggests to me that some component is heating up beyond its
> specifications... but a transmit component affecting the receiver?
>
> I have no clue.
>
>
> 2. I have a 35KW AM BC station on 1260KHz 1KM (3500') feet away, and I
> have a custom BC filter with an 85+dB notch at 1260; Its 3rd harmonic at
> 3780 KHz is barely perceptible. I don't hear the station when receiving.
>
> However, when I go to transmit in SSB/FM/AM (that is engage PTT) I don't
> hear it either unless I have the signal monitor function engaged even
> with only a Heil adapter plugged into the front panel input.
>
> With a Heil headset mic plugged in to the adapter, the BC signal is
> strong enough to modulate the transmission, often high enough to trigger
> problem (1) above.
>
> To me this suggests that the BC station is being rectified even in the
> short length of the Heil adapter cable, and even more so in a normal
> length mic cable. But, strangely, not in the earphone part of the Heil
> headset cable.
>
> The solution would seem to be to create a custom mic adapter wound
> around a special low frequency toroid (type 77).
>
> Opinions?
>
>
> Bob, w3idt
> .......
> . Robert F. Teitel, W3IDT
> .
> . w3idt@comcast.net
> . w3idt@arrl.net
> ........
>
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