Trig ty91 vhf radio

[Mauleguy]

I have a very faint click noise in my radio, it makes the same noise whether the engine is running or not. It really bugged me the first few hours, I am slowly getting use to it, 20 hours on the new Cub now. I guess in another 100 I will forget about it, any suggestions. Brand new radio

 

[skywagon8a]

Perhaps this is a dumb question, but do you also have a transponder? Could it be that it is actually the transponder reply transmission which is bleeding through?

 

[wireweinie]

Transponder installed? Any other electrically active electrical equipment installed? Are you sure the noise is coming from the radio and not the intercom?

Plug headset into the pilots position. Listen for the noise and pull the circuit breakers one at a time and see which one makes the noise go away. This should narrow down the noise source.

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[wireweinie]

Crap! He beat me to it!

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[Mauleguy]

Yeah I have the Trig Transponder with ADSB also. I am using the built in intercom of the Trig Radio.

Thanks I will try the breakers

 

[OLDCROWE]

Yeah I have the Trig Transponder with ADSB also. I am using the built in intercom of the Trig Radio.

Thanks I will try the breakers

Been there done that with the same setup but separate intercom, Pierce and I chased that noise six ways to Sunday and finally moved the transponder antenna to the tail clean out on the belly of my Cub and no more tick, tick, click...

Disconnect power to the transponder and I bet it goes away.

 

[wireweinie]

I figured you'd chime in on this one, lol.

Web

 

[OLDCROWE]

I figured you'd chime in on this one, lol.

Web

That noise is annoying as hell, I wouldn’t even wish it in Eaton.

 

[txpacer]

I have a low level background noise in my Trig with the intercom off. The volume is independent of the radio volume, so I just turn down the headset volume, up on the radio, problem solved.

 

[RaisedByWolves]

Been there done that with the same setup but separate intercom, Pierce and I chased that noise six ways to Sunday and finally moved the transponder antenna to the tail clean out on the belly of my Cub and no more tick, tick, click...

Disconnect power to the transponder and I bet it goes away.

Weird. Don’t have that with mine


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[Bearhawk Builder]

Been there done that with the same setup but separate intercom, Pierce and I chased that noise six ways to Sunday and finally moved the transponder antenna to the tail clean out on the belly of my Cub and no more tick, tick, click...

Disconnect power to the transponder and I bet it goes away.

Did you have the TN72 ADS-B also with the TA70 WAAS antenna? I've been curious if that antenna would have any effect on the com if too close to each other.

 

[wireweinie]

Did you have the TN72 ADS-B also with the TA70 WAAS antenna? I've been curious if that antenna would have any effect on the com if too close to each other.

Shouldn't cause noise in the headset. The GPS antenna is passive, meaning it only receives, never transmits. On the other hand, the transponder antenna transmits LOTS of power. Usually not a problem if comm antennas are on top.

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[wireweinie]

I have a low level background noise in my Trig with the intercom off. The volume is independent of the radio volume, so I just turn down the headset volume, up on the radio, problem solved.

Have you swapped headsets, brands/models? Noise only with engine running or not?

Web

 

[txpacer]

It hasn't been much of a problem, so I haven't spent much time chasing it.

Have you swapped headsets, brands/models? Noise only with engine running or not?

Web

 

[OLDCROWE]

Weird. Don’t have that with mine


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You were there when we were working on it... It even persisted with a different head.

 

[OLDCROWE]

Have you swapped headsets, brands/models? Noise only with engine running or not?

Web

What made us go on the hunt was we even heard it with a set of DC's without noise cancelling.

 

[wireweinie]

You were there when we were working on it... It even persisted with a different head.

?

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[Steve Pierce]

Mine is quiet unless I monitor both frequencies and have my strobes on and I here a slight click. Was gonna ground the strobe power supply direct to the battery but haven't gotten around to it. I usually fly with Tony and we know where each other are until he gets down into the weeds with that cammo paint job but his wig wag LED landing lights show well.

 

[wireweinie]

What strobes?

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[Steve Pierce]

Whelen with a single power pack on the battery shelf behind the baggage.

 

[wireweinie]

Ouch. That's a tough system to soundproof. Separation is about the only way to minimize noise. Rarely able to eliminate it completely.

The noise is usually generated from the leads from the box to the tubes and if it's the original grey stuff, not shielded well.

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[Steve Pierce]

I should just $it can it and go on a diet so I can get my EW w/pilot down around Tom's.

 

[OLDCROWE]

?

Web

Steve had a new uninstalled unit that we swapped mine with.

 

[wireweinie]

But the head just has the controls. The R/T unit is the part that puts out the power.

Web

 

[Steve Pierce]

Swapped the whole enchilada.

 

[RaisedByWolves]

You were there when we were working on it... It even persisted with a different head.

Guess I should turn mine on once and awhile.


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[KevinJ]

Guess I should turn mine on once and awhile.


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.....or take it out

 

[fancypants]

Is it about a 1 cycle per second ticking noise? When you push a button or twist one of the selector knobs on the Trig control head, does the ticking cycle start over, or tick faster for a short while? If so, I bet it's the same noise I was trying to track down in my install.

With absolutely nothing else connected anywhere in the plane - electrical system rewired from scratch, using the Trig internal intercom - I heard a ticking noise, about 1 cycle per second on the output of the Trig. After some experimentation, I found I could get the ticking to change by fiddling with the buttons and knobs. This suggested to me that it was something to do with the interface between the control head and the radio. I then discovered I could get it to stop entirely by disconnecting one of the TMAP lines going between the control head and the radio unit. According to one of their install documents, TMAP is the RS485-based serial protocol the control head and radio unit use to communicate. My guess is that there is a 1 Hz update/polling clock as part of the system design, and there's a design flaw somewhere that's allowing the serial data communication itself or that clock signal to leak into the intercom audio path.

So, what to do about it? I seem to remember trying various shielding options for the TMAP lines, but that didn't do anything. Then I found some references to firmware updates for noisy radios on their website, so I sent the control head and radio to Mid-Continent (Trig's US service center) and had them update both. I think this was covered under warranty, but probably had to pay shipping both ways. I can't remember if the updates made a noticeable difference, but I know it didn't make it any worse.

Finally I tweaked levels on the radio/intercom and headset so that the noise was minimized, just as txpacer suggests above. It's probably still there if I try to hear it, but it's not too noticeable with the engine running. I put on about 150 hours since May and I haven't given it much thought since then.

Curious to know if others can reproduce the change in behavior with the knob twisting and button pushes.

 

[wireweinie]

TMAP A and B lines flip flopped?

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[Bearhawk Builder]

Did you twist the TMAP wires?