ICOM A2 radio headset adaptor and sidetone

[Alan George]

I have made up a headset adaptor for our ICOM A2 radio that is panel mounted and it works fine but there is no sidetone i.e. I cannot hear myself in the headset when I am transmitting and it is surprisingly annoying. I understand the ICOM A2 does not have sidetone as standard so has anyone found a method to put the voice transmission into the headset. Our aircraft is a single seater so there is no intercom fitted.

Thanks for any help, Alan.

[ROB THOMASSON]

The snag is that without sidetone from the radio you are going to have to build a pre amp and feed some of the output back to your headphones. You could get an intercom kit from Maplins as a suitable base but if the battery goes flat you lose all radio unless you have the ability to unplug it if necessary.
By the time you've bought the kit, the plugs and sockets etc and played around it might be easier just to buy an aircraft intercom and plug it all together. It'll be reliable and you could sell it on later if you need to. I got one off Afors for £60 and job done.

[Alan George]

I have used a Maplin box to mount the sockets for the headsets so that could just as easily be an intercom.

I like the Flycom intercom as single cable powers both it and the Icom radio, a neat solution. But it is intended for Flycom headsets so would need another adaptor for a 2 plug GA headset like David Clarks, not so neat.

The Pilot PA200 intercom takes the 2 plug GA headset directly. But it needs a battery for power and I cannot see myself accessing the intercom on a regular basis to change the battery.

What model of intercom did you use? Any suggestions that give the benefits of 2 plug GA headset and aircraft power?

[Rob Swain]

In your position I'd buy a Sigtronics intercom and make the properly documented (and supported?) mod for 'artificial' sidetone.

OK, I admit this is not the cheapest option, but the Sigtronics is small, cheap(ish), reliable and has the proper 'straight through' wiring from P1 headset to radio and back again in off / standby / failure mode.
It is also very forgiving of putting additional inputs, like GPS audible warnings, though to the headsets.