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Avionics settings suggestion?


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Hello,


I hope you can make sense of this question, I am a newbie so please go easy.

I purchased my first plane, a 20C a few months ago.  For reasons too lengthy to mention here I wanted to have the co-pilot able to use the radio and bought a push to talk plug.  Unfortunately it didn't work.  When I took her in for maintenance I mentioned it to my AME who said he'd play with it and see if he could get it working.  I don't know if he got it working or not but when I flew it home I discovered that I (in the pilots seat), either have to have it set to radio a switch to send/receive on radio or on intercom to listen/talk to passengers.  I used to be able to hear both and just press my push to talk to send on the radio.  Now I have to operate a three-way switch on the panel which is visible in the top far right of the photo.

Rather than assuming the AME rewired something poorly without testing it, is there a setting on the audio panel or somewhere else that might cause it to behave like this?

Thanks bunchly!

Dave

 

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http://sigtronics.com/_pdf/air_pdf/air_intercom_pdf/spa-400.pdf

Dave - The picture isn't very clear, but it looks like you have a Sigtronics SPA-400 intercom. The link above includes the operation and installation manual. A review of the manual might help. If the issue continues it would be helpful to include a little bit more information on your post. What radios, audio panel, what happens at what setting etc. 

I assume the PTT you added plugs into the microphone jack and has a receptacle for the headset. Make sure that the Co-pilot microphone jacks is wired to the Intercom Co-pilot PTT wire. For starters try to look at the backside of the jack and confirm to it is connected to 3 wires. 

 

 

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Thanks, I will read up and look when I get back into it tomorrow; I didn't have much time to play with it as I had to outrun snow. 

This is a list of what I know I have (so far):

NAV/COM KING KX-170B, COM Bendix/King Ky 97A, Audio Panel Narco CP 135, KING KT76, NARCO ADF 141

Edited by DrQuinn
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I've discovered your problem, Dave! You took your plane to the wrong person. My Aviation Medical Examiner doesn't know much about radios. :P

Review the instructions and check the connections. Write down all of the model numbers and report back with them if you're still having trouble. If you'd like, I'll check how the right PTT is wired in in my C model. 

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Thanks Hank ... lol I said go easy - besides, mine just might!  I don't have a push to talk on the co-pilot yolk, I purchased a plug-n-play type.


I don't think it's an SPA-400 intercom system as it doesn't look like the switch in the middle of the SPA-400 is a three-way (Radio, Intercom, Off).  It doesn't look like it is marked with the company name or type but I will double check tommorow.

 

Dave

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On most of the add on PTT switches, you typically need to modify them to be compatible with the intercom.  Many of them rely on the switch to complete the circuit.  What you need is continuity of the mic circuit, and you only want to use the switch to trigger the PTT.  Ask your mechanic what they changed.  You should not need to switch anything in order for you to use your radio.  

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