Intercoms

Hello,

I am going to set up my RV-9A with a single SL-40 comm for now, and I know I want input for music, a trafficscope, and the Garmin 296 terrain squaker. Can I have all these come into a intercom like a Fightcom 403?

Pete

I think the Flightcom 403 has two aux inputs, and the cheaper 403mc has only one. Sounds like with the setup you listed you'll need three audio inputs, though. I don't know of anything short of a full blown audio panel that will let you do that. But, there are audio mixers available (a do-it-yourself one is here) so you could mix 2-into-1 and then run that into one of your two aux inputs.

Also be aware that the Garmin 396 is the one with the audio output for terrain and other alerts - the 296 just has an internal beeper.

cheers,
mcb

Thanks Matt

I am undecided on the 296/396 so the point might be moot. Maybe less toys is better ;-> I'll look at the mixers - Thanks.

Pete

Audio mixer

http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1113496059/1#1

Check the above out.

For stereo you may look into DRE 244e or a PS engineering. G

Audio mixer

It is possible to build a simple audio mixer without active circuits.

Go to
http://www3.telus.net/aviation/vx.html
and download the datasheet for the AMX-1A.

The schematic and application note shows how to mix comms, audio alarms and external music inputs into a mono audio system.

It's pretty simple, with no auto-mute on the music input. It also works directly with Sigtronics intercoms, but the concept can be used with others.

Vern Little, RV-9A

Hi Vern

Vern,

Good luck with the 1st flight. I looked at your intercom interface - it is very well done - i wish i had put in a Sigtronics intercom.

What value resistors did you use for the audio inputs? I used 150 Ohms and a 10uF cap for isolation. Since I am not a EE, that does not mean a lot to me, i followed the lead of my buddy the EE.

Low cost audio panel

While this may be more than you are interested, it does include an intercom, switching for two coms and two navs (no ADF, DME) and does not have a marker beacon receiver.

But it does have four inputs for warnings. They are known as unswitched inputs.

www.ps-engineering.com/pma4000.shtml

Maybe a few members here can comment on their experience with this audio panel. It sells for about $775

Mark

Intercom

You might try RST Engineering.
Build your own Audio Panel from a Kit.
Its very satisfying and a quality product
Provides all of the growth you may need in the future.
Under $ 300.00
15 to 20 Hours build time

The RST 564 and RST 565 Audio Panel includes all of these features:

Automatic speaker and headphone switching between COM 1 and COM 2 when the transmit switch is selected to that radio (or separate audio and microphone switching at the option of the pilot).
Built-in full-feature intercom with front-panel volume and squelch switches.
Provisions for one to four aviation headsets.
Isolated and individually switched inputs for 8 "radios" (COM 1, COM 2, ADF, AUX, DME, NAV 1, NAV 2, and MKR.)
Detailed construction and operation manuals.

http://www.rst-engr.com/

Al Smith
RV6 FF
N 495AB
Keos

resistor values

Pete, what you've done will work. The resistance value is not critical, and the capacitors don't affect the audio at all.

Based on the number of emails that I get on audio systems for aircraft, it's the most difficult wiring challenge in the entire airplane.

Anyway, keep plugging away, it sounds like you are getting closer to the goal line.

My inspection is now complete (with no snags). When I get the regional guy to sign off on the paperwork, I'm ready to fly.

Vern