[TenTec] Orion II Transmit Audio issue(s)...

Byron Cordes byroncordes at icloud.com
Wed Dec 22 20:31:13 EST 2021

I would try the 5 pin din connector in back of radio  and see if the problem is still there.  I had a Orion that would act up occasionally and using the five pin din in the back the radio for audio solved it.  
73s Byron AC9PA 

On Dec 22, 2021, at 4:51 PM, Bob, W3IDT <w3idt at 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).


Bob, w3idt
. Robert F. Teitel, W3IDT
. w3idt at comcast.net
. w3idt at arrl.net

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