Dual GPS/Com without an Audio Panel

[todehnal]

I'm and RV-12 builder and I wish to add an extra panel mounted GPS, or possibly a GPS/com to Van's Panel. I would like to do this without an audio switching panel, due to weight, panel space and, of course, cost. How about putting in simple switches for com 1 and com 2 selection, as well as nav 1 and nav2 selection to the Dynon EFIS? If someone has experience and/or knowledge on this matter, your help with the correct switch selection and how to hook it up would be greatly appreciated. If I'm out in left field here, just let me know, but I sure would like to try this

By the way, I'm building an E-AB, not an E-LSA

Example:
The standard 12 panel comes with:
Dynon 180 EFIS
496 GPS
SL40 Com
GTX 327 Xponder
Flightcom 403 Intercom

Want to add and use switches for:
GPS 155XL or 300XL GPS/com

Thanks in advance

Tom

 

[Mel]

No problem whatsoever.

I've been running dual com radios for many years without an audio panel.
You'll just need a DPDT switch to switch the PTT and mic audio.

 

[todehnal]

Now for the Dynon

I've been running dual com radios for many years without an audio panel.
You'll just need a DPDT switch to switch the PTT and mic audio.

Thanks Mel! I wasn't sure if it was a problem or not, allowing the standby radio audio, to float, without a load. But, if you have been doing it, it should also work for me. Thanks.

Now, if I can just swap GPS inputs to the Dynon, I'll be in fat city

Tom

 

[flickroll]

Now, if I can just swap GPS inputs to the Dynon, I'll be in fat city

Another switch to switch the serial input should take care of that....

 

[Mel]

Just a minute...

Thanks Mel! I wasn't sure if it was a problem or not, allowing the standby radio audio, to float, without a load. But, if you have been doing it, it should also work for me. Thanks.

I'm not quite sure what you mean by allowing the "standby radio audio" to float. I'm talking about switching the MIC audio, not the receive audio. The receive audio needs to be loaded. In other words, you will be able to hear both receivers at the same time. You don't want to switch the receive audio.

 

[Walt]

I have dual SL40's and use a 4PDT to switch audio, mic, PTT and data (data from the 696 to tune the selected radio). You can isolate and tie the audio outputs together or switch them, however with the monitor function of the SL40 there is no reason to tie them together unless you want to monitor 4 frequencies at once

 

[todehnal]

Additional Thoughts

I'm not quite sure what you mean by allowing the "standby radio audio" to float. I'm talking about switching the MIC audio, not the receive audio. The receive audio needs to be loaded. In other words, you will be able to hear both receivers at the same time. You don't want to switch the receive audio.

You are right, Mel, I could control the receive audio selection with volume knobs, but Walt has some interesting comments about his dual SL40 installation.

Tom

 

[L.Adamson]

however with the monitor function of the SL40 there is no reason to tie them together unless you want to monitor 4 frequencies at once

I often listen to three frequencies at once. The local CTAF, an air to air channel, and air traffic control as I'm under the Class B veil. In this case, I do have an audio panel.

L.Adamson --- RV6A

 

[breister]

Another consideration - you might wish for the standby radio to be muted when receiving on the primary. This can be accomplished by using a multi-pole switch and routing the standby radio audio to the intercom's music input (with appropriate resistors to keep the volume approximately the same - music input tends to be more sensitive).

You don't want the standby radio to block out incoming transmissions to you.

 

[RV6_flyer]

I often listen to three frequencies at once. The local CTAF, an air to air channel, and air traffic control as I'm under the Class B veil. In this case, I do have an audio panel.

L.Adamson --- RV6A

Ditto. GX60 GPS/COM, SL30 Nav/COM, Marker Beacon, and Entertainment Center all going at the same time. 4 Comms, one Nav, and entertainment all at the same time.

Another consideration - you might wish for the standby radio to be muted when receiving on the primary. This can be accomplished by using a multi-pole switch and routing the standby radio audio to the intercom's music input (with appropriate resistors to keep the volume approximately the same - music input tends to be more sensitive).

You don't want the standby radio to block out incoming transmissions to you.

The bad thing about this is that some times you want Comm 2 as the primary. I just keep the volume of the not primary comm turned down a little lower.

Electric Bob has an audio summer circuit on his AeroElectricConnection.com web site. I cannot find a working link while I am posting this so you will need to try to find it.

I did not use Electric Bob's audio summer circuit in my airplane but did use a 100 or 1K resistor in series with the audio output of each Nav and Comm signal as I tied them together to the comm input on the intercom. The intercom had a separate input for the entertainment where it mutes to a lower level when one of the comm or nav signals is hot. Done like this but to the intercom instead of the headset jack. http://www.aeroelectric.com/PPS/Audio/DualCommAudio.pdf

 

[todehnal]

I did not use Electric Bob's audio summer circuit in my airplane but did use a 100 or 1K resistor in series with the audio output of each Nav and Comm signal as I tied them together to the comm input on the intercom. The intercom had a separate input for the entertainment where it mutes to a lower level when one of the comm or nav signals is hot. Done like this but to the intercom instead of the headset jack. http://www.aeroelectric.com/PPS/Audio/DualCommAudio.pdf

Thanks Gary,
The schematic answered all of my questions

Tom