Marine band amphib radio install

James331

James331

Ejection Handle Pulled
Joined
Apr 18, 2014
Messages
20,309
Display Name
Display name:
James331
Hey guys,


Im looking to add marine band and general audio input/output capabilities to my plane.

The plane has a spare VHF antenna on the belly which is not connected to anything, ontop of the existing dual top antennas for the garmins, plus a com3 on my audio panel which isnt being used for anything.

What Id like to do is install a jack for the belly antenna under my panel for a handheld marine radio.

Also adding a TRRS jack to my panel, wired into the Garmin GMA340 (Comm 3)

http://www.cablechick.com.au/blog/understanding-trrs-and-audio-jacks/

trrs-diagram1.jpg

trrs-diagram2.jpg


Id like the TRRS to have stereo audio output to the headsets so I can use it for music from my ipod, or swapping over to the marine handheld to use the audio in and out from com 3 with a spliter cable from the panel TRRS jack to a handheld marine radio, if that makes sense

Is this doable?

Any good makers for a nice flush mount TRSS and VHF jack?

Any recommendations for a nice handheld marine radio?

Would the VOX feature work here, basically so I won't have to hit my yoke PTT as well as holding down the radios PTT button?



Thanks!
 
Last edited:
So I found the wiring installation manual for the Garmin 340.

Looks like com 1-3 only don't support independent right and left stereo, they just take mono and pipe it to both L and R in the headset?

So if I used it for the marine handheld as well as the iPod, I'd have to have the iPod only in mono, not stereo?

Also I'm not sure what "com 3 key" is? Guess that's the PTT activation on the radio, which I wouldn't have to worry about if the marine handheld utilized VOX?

Wonder where I could find out if I need to use the "load" option too.

image.jpg


image.jpg


Anyone? ....Bueller?
 
Last edited:
far as I know all aircraft com radios are mono.

Stereo comes from the intercom portion. If the 340 contains a stereo intercom then it should have some sort of optional stereo aux line in for music.
 
So iPod to stereo music-in jack and com 3 wired to a jack/plug you mention should work.
 
The CG air aux guys all add marine radios to their planes maybe ask them?
 
Com 3 key is what sends the PTT switch signal to the transmitter to transmit.
 
You are in WAY over your head if you think all you have to do is connect your aircraft headset through an audio panel to your marine transceiver.

Jim
 
weirdjim said:
You are in WAY over your head if you think all you have to do is connect your aircraft headset through an audio panel to your marine transceiver.

Jim
Click to expand...
Well, he's on the right track to get it in the intercom... but the radio install isn't even touched in the initial question.

What kind of coax is run for the extra antenna? Impedance matching is important. Is there an easy way to legally install the radio in the aircraft and the required antenna? The existing antenna is likely completely mistuned for marine band. Piping it to the intercom is the easiest bit of the install.

In general, radio installation (in things other than aircraft, at least) isn't terribly difficult. My experience is generally limited to ham installs in four wheeled land vehicles, though. In an airplane, I'd imagine the paperwork may be a bit tricky here since it's not going to be TSO'd radios or antennas.
 
Wow ! What a way to make a lot of extra work for yourself. I too fly an amphibian and for the very FEW times that a marine band radio is needed I just use a hand held one.
 
I'm thinking I might just use the handhelds antenna, though this would still be a good use for com 3.

There is a stereo for the music input, just mono for the comms.
 
mkosmo said:
Well, he's on the right track to get it in the intercom... but the radio install isn't even touched in the initial question.

What kind of coax is run for the extra antenna? Impedance matching is important. Is there an easy way to legally install the radio in the aircraft and the required antenna? The existing antenna is likely completely mistuned for marine band. Piping it to the intercom is the easiest bit of the install.

In general, radio installation (in things other than aircraft, at least) isn't terribly difficult. My experience is generally limited to ham installs in four wheeled land vehicles, though. In an airplane, I'd imagine the paperwork may be a bit tricky here since it's not going to be TSO'd radios or antennas.
Click to expand...

I really am not intending to start a holy war here, sir, but please don't add to the misinformation quotient.

Thanks

Jim
 
weirdjim said:
I really am not intending to start a holy war here, sir, but please don't add to the misinformation quotient.

Thanks

Jim
Click to expand...

Do you have anything constructive for me Jim?
 
Jim's snark was that the preceding post had a lot of issues. As for legality, TSO is neither necessary nor sufficient for a radio installation in an aircraft. By the way, your installation would be illegal under FCC rules to use except on the water. The exemption for VHF station licenses only apply to voluntary craft operated on the water.

The antenna mismatch of a VHF marine frequency into a VHF aviation band antenna is going to be substantial. Most aviation antennas are broadband to a certain extent but you're asking a lot here. The transistor finals in your portable are just going to put out substantially reduced power in such situation. Of course, if you're only trying to range boats in your immediate vision, it will probably work. Not much power is required.

You don't indicate the model of the radio (Garmin does NOT make handheld marine stuff). The speaker out isn't going to be a problem. Jim's previous comment is an allusion to the fact that aviation microphones emulate old carbon mic telephone transmitters and not the average mic input these handhelds use. That being said, you may or may not be able to get it to work directly. I've found that a lot of intercoms/audio panels are more tolerant to the mismatch than one might reasonably expect. I used to use my aviation headset with a VHF business band radio at the local racetrack. It wouldn't (expected) work plugged directly into the radio, but it would if I ran it through my portable intercom first.
(I suspect the intercom didn't much need the mic bias the radio would be expected to provide and the input was of sufficiently high impedence that it just worked).

That being said, you still may need to provide a small circuit to get it to work.

You don't have to worry about stereo. All the radio inputs to the audio panel are MONO, it automatically replicates them to the LEFT and RIGHT headphone channels.
 
flyingron said:
Jim's snark was that the preceding post had a lot of issues. As for legality, TSO is neither necessary nor sufficient for a radio installation in an aircraft. By the way, your installation would be illegal under FCC rules to use except on the water. The exemption for VHF station licenses only apply to voluntary craft operated on the water.

The antenna mismatch of a VHF marine frequency into a VHF aviation band antenna is going to be substantial. Most aviation antennas are broadband to a certain extent but you're asking a lot here. The transistor finals in your portable are just going to put out substantially reduced power in such situation. Of course, if you're only trying to range boats in your immediate vision, it will probably work. Not much power is required.

You don't indicate the model of the radio (Garmin does NOT make handheld marine stuff). The speaker out isn't going to be a problem. Jim's previous comment is an allusion to the fact that aviation microphones emulate old carbon mic telephone transmitters and not the average mic input these handhelds use. That being said, you may or may not be able to get it to work directly. I've found that a lot of intercoms/audio panels are more tolerant to the mismatch than one might reasonably expect. I used to use my aviation headset with a VHF business band radio at the local racetrack. It wouldn't (expected) work plugged directly into the radio, but it would if I ran it through my portable intercom first.
(I suspect the intercom didn't much need the mic bias the radio would be expected to provide and the input was of sufficiently high impedence that it just worked).

That being said, you still may need to provide a small circuit to get it to work.

You don't have to worry about stereo. All the radio inputs to the audio panel are MONO, it automatically replicates them to the LEFT and RIGHT headphone channels.
Click to expand...


The more I think about it the more I'd rather just have use the handhelds antenna, so long as it works.

Not 100% sure which handheld I want to get just yet, I'm open to suggestions.

As for the mono only, the music in function appears to have stereo input and output.

image.jpg



So no way using VOX I could have a setup for the com 3 where I could use it with different handhelds?

Thanks!
 
I had an aviation handheld that I ran into the music input of my intercom. I only had one radio in that plane and I wanted to listen to the ATIS when IFR. It was listen only through the headphones. If I wanted to talk on it I had to push the button and hold it to my mouth. It worked only within 5 miles with its own antenna. I had an antenna installed on the plane and it worked quite well. If I really wanted to speak into it with headphones, I could plug aviation headphones into it with an adapter and I could listen/talk through the headphones.

I traveled with my Amphibs up the inland passage and around Vancouver island and I can see how having a marine radio could really help in an emergency. If I had to land on the water, I'd still be in trouble because I need a rescue and I'd be floating around carried by currents to who knows where. And many of the boats monitor the marine hailing channel 16 or whatever it is. There are lots of boats up there.

YMMV
 
Last edited:
The music is stereo, the radios are NOT (as shown by the pinout).
 
You must log in or register to reply here.
Back
Top