Radio squeal, "echo"- on only one mic jack?

rottydaddy

rottydaddy

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Just curious as to any general idea about this one...

The Champ I've been flying has a basic two-channel flip-flop type com radio with a two-place intercom (don't have make and model handy, but I don't think it matters). PTT on each stick.
Last couple of flights, I've noticed that when I key my PTT on certain (tower) freqs, I can hear a squeal as if being "stepped on", and apparently ATC hears it too. Almost got turned out of one Class D pattern today, until the instructor took over comms.
Back at Brown, Tower told me I seemed to be coming in on Ground and Tower freqs simultaneously, even though you cannot select "transmit" on both channels; it's just got the flip-flop switch. And when I spoke to them on both freqs, there was no squealing; only the "echo" described.
There may be two different things happening here...


Haven't tried swapping headsets, but it seems unlikely that it's my headset mic, anyway... especially the dual-transmit thing.
I've never encountered this before- anybody else?
 
The dual "transmit" thing could have been on the ATC end. They can listen to two channels at once and may not have realized that they had both selected. I would check for a headset or headset incompatibility problem first.

See the the squeal can be repeated, then move the headset to another jack to see if the problem moves with it. If you get nothing, try having the two headsets plugged and move them around.

If nothing or it does not move it may be related to the intercom and/or intercom wiring. Do you have an audio panel that has a bypass the intercom select on it?
 
No audio panel- this is a plane that came from the factory with no radio, and no electrical system. :D

There's the transceiver, which has a freq flip switch but no other transmit/receive options, and a little intercom box, which has squelch, volume, and an iso switch which has no effect on this anomaly.

As for Tower listening to both freqs, I'm sure they do at Brown, but I wasn't transmitting on both, because I can't in that plane... unless there's ross-talk or something related to the flip-flop switch (?).
 
rottydaddy said:
As for Tower listening to both freqs, I'm sure they do at Brown, but I wasn't transmitting on both, because I can't in that plane... unless there's ross-talk or something related to the flip-flop switch (?).
Click to expand...
I am not saying you were transmitting on both. I am saying they were listening to both and therefore could not tell if it was coming over one freq or the other therefore the controller thought it was over both freqs.
 
smigaldi said:
I am not saying you were transmitting on both. I am saying they were listening to both and therefore could not tell if it was coming over one freq or the other therefore the controller thought it was over both freqs.
Click to expand...
Maybe... they described it as a sort of "echo".
At any rate, there's not much I can do about it, but I'll be sure to try another headset in that jack next time.
 
rottydaddy said:
Just curious as to any general idea about this one...

The Champ I've been flying has a basic two-channel flip-flop type com radio with a two-place intercom (don't have make and model handy, but I don't think it matters). PTT on each stick.
Last couple of flights, I've noticed that when I key my PTT on certain (tower) freqs, I can hear a squeal as if being "stepped on", and apparently ATC hears it too. Almost got turned out of one Class D pattern today, until the instructor took over comms.
Back at Brown, Tower told me I seemed to be coming in on Ground and Tower freqs simultaneously, even though you cannot select "transmit" on both channels; it's just got the flip-flop switch. And when I spoke to them on both freqs, there was no squealing; only the "echo" described.
There may be two different things happening here...


Haven't tried swapping headsets, but it seems unlikely that it's my headset mic, anyway... especially the dual-transmit thing.
I've never encountered this before- anybody else?
Click to expand...

Your old radio is broad casting on a wide band width and covering both frequencies, so it is stepping on its self.

I'll bet it is not (FCC) legal to transmit on this radio.
 
NC19143 said:
Your old radio is broad casting on a wide band width and covering both frequencies, so it is stepping on its self.

I'll bet it is not (FCC) legal to transmit on this radio.
Click to expand...

How could it do that with only one headset/PTT and not the other? :confused:
 
Well, somebody fixed the IC... then the radio was picking up tons of FM stuff out of Mexico while in flight.:rolleyes:

But that was just the squelch, as it turned out. :)
 
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