V16 can it feed to an intercom like Dynon SV-intercom-S2

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azminear@gmail.com
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Joined: Tue Feb 01, 2022 11:59 pm

V16 can it feed to an intercom like Dynon SV-intercom-S2

Post by azminear@gmail.com »

I have a V16 transceiver with a Vega control head, I need to get another audio and mic input/outputs for my 3rd passenger. Can I use the Audio out to feed into an intercom system and pass the intercom out back to the co-pilot mic input? Anyone done this that might give me some guidance?
rainier
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Re: V16 can it feed to an intercom like Dynon SV-intercom-S2

Post by rainier »

Sure - it's no different to any other aviation COM radio.

As both the intercom as well as the V16 have their own volume and input level controls you need to setup the V16 (or any other radio) so it gets the correct mic input level and the audio output should be set to a level the intercom can work with. Once that's done you would not touch the radio's audio controls again and do volume control via the intercom.

The link between radio and intercom requires some thought to prevent unintended side effects which could affect audio quality - in particular during transmit where there is a chance that transmitted signal could be coupled to the audio connections between intercom and radio causing havoc.

A general rule of thumb is to keep the audio levels as high as possible - that means there is more "distance" between interfering signals and the audio signal you are interested in.
So for the V16 mic input - you would adjust that to be as insensitive as possible - and then adjust the intercom output to the radio as high as possible. As long as you do not get into clipping or distortion range you are good.
The other way around - the V16 audio out should be as high as possible and the intercom input from the radio adjusted as low as possible to compensate.

Finally - to arrest and feedback issues during transmit - you may need two ferrites - each to be mounted on the audio lead physically close to the input you need to protect. Usually you can get away with just one - at the V16 mic input. The audio output is low impedance and much more tolerant as a result.

In difficult cases you can also wire a small 1:1 600 ohm audio transformer between radio and intercom, even two one for each direction. The advantage of this is that RF can't usually transfer via the transformer and you completely avoid the pesky "ground loop".

Use shielded wires for the audio - ground the shield on one side only. Run audio ground as a separate wire inside the shield. Two core shielded wire often used for computer type communications works well.

One possible "gotcha" is the "sidetone" during transmit - some intercom systems have their own sidetone and the sidetone from the radio can interfere. If this happens - switch the sidetone in the V16 off using the setup.

Also switch the intercom of the V16 off - just turn the V16 intercom volume right down to zero and only use the RX volume on the V16. Switch the V16 VOX off - you should now use whatever noise gating your intercom uses. If you leave the V16 VOX on and use the external intercoms noise gating as well - the result will likely not be good.
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