Icom IC-A200 to Sigtronics intercom

I am installing an Icom radio and a Sigtronics intercom in my -7A, and have a question about connecting the two. The wiring diagram for the intercom shows 3 wires that connect to the radio: one to the radio headphone output, one to the "key input of the aircraft radio" and one to the "mic input of the aircraft radio". The headphone connection in clear, but I am confused about the two mic connections. The radio wiring diagram shows a yoke-mounted communication/intercom switch between the radio and the microphone jack to use the built-in intercom feature, but I do not need to use the switch, I believe. If anyone is familiar with the Icom radio and can offer advice, it would be much appreciated. Hope this is clear enough.
Thanks.
Ward

Sorry

Ward,

Sorry, I don't have an ICOM radio, but recently installed an SPA-400 in my Grumman.

I have a Narco Audio Panel and thing got a little tricky. At first, I could hear myself, but not the radios. Called Sigtronics, and they said send the intercom back for repair and sent me a loaner. Loaner did the same thing. My avionics guy did some digging and found the Narco Audio Panel needed a resistor added to make the intercom work properly. I don't know why Sigtronics didn't tell us that on the phone. He found it on the Sigtronics website. Apparently, some audio panels/radios require little "tricks" to make them work right with the Sigtronics intercoms.

Apparently the ICOM may be on of them. Have you looked at this?

http://sigtronics.com/air/pdf/SPA-400_ICOM_A-200_Inst.pdf

Also look at some of the instructions found here:

http://sigtronics.com/air/tecavi.html

Hope this helps!
Phil

Ward,
I recently wired my Icom with a PS engineering intercom and things came out great. I understand what you mean about the mic switch, but can't remember exactly what the diagram looked like or what I did. I do remember that no yoke switch was used. When I get home tonight I'll email you my wiring diagram.

To make wiring a Sigtronics intercom easier (including the series resistor for the ICOM), you can use the AMX-1A at www.vx-aviation.com.

It also allow you to interface alarms and other audio sources.

The Sigtronics intercom is unique in it's ability to add audio sources without using an audio panel or iso amplifier. I run my RV-9A with several audio sources this way. The key is to have isolation resistors in series with any audio source that is low impedance.

Often, you can't tell until you wire the audio device in. It usually does no harm to put the resistors in. The AMX-1A does this for you, too.

Vern

Thanks!

Man, I love these forums. Thanks for all of the quick replies. The PDFs are great and the VX connector looks interesting! I'm all for simplicity.
Thanks again.
Ward

Ward, Steve and whom ever has an ICOM 200, let us know what you yhink of it. I'm considering one as a second com.
Larry

I'm flying behind and Icom in my RV6 (connected to a PSE intercom) and really like it. It's not as fancy or probably not as robust as an SL-40, but then again it's only 1/2 the price! My opinion of the Sigtronics stuff however is 180 degrees opposite. I won't bash it, but I won't use it either.

Just my 2 cents as usual!

Cheers,
Stein.

Ward,

I'm using the same two items on my -9 and have just worked through the connections but haven't started wiring anything yet.

The iCom has three mono inputs and then feeds the intercom.

I plan on connecting the Dynon EFIS and EMS to two of these and will run the Garmin GPS 396 stereo out to the Sig stereo in. This will leave me one other mono input to the radio.

If the intercom goes Tango Uniform the EFIS and EMS warnings will feed through the radio to your headsets, so the manual states. However, you can put a set of jacks before the intercom, should it die and just plug your headset in there. I do not plan on doing this as I will have a simple D/N VFR ship and could really care less if the radio dies. The radio is not a safety issue for VFR flight, IMHO.

Here is a schematic of what I plan on doing. Hope it helps.

Sigtronics

Stein,
I would be anxious to hear off-list the details of the Sigtronics.
By the way, my order arrived today in great shape! Thanks. Now I can mount my fuse blocks.
Ward
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