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PostPosted: Sun Dec 30, 2007 7:46 pm
by Banned my Admin

PostPosted: Mon Dec 31, 2007 12:11 am
by JPXman
i use:

Icom A4
Gentex 41-1 helmet rewired to civvie impedances
braided tinned copper shields on plug wires (i have 4 of them with the JPXs)
remote mounted antenna on end of boom tube

and i get great reception/transmission

with attention to RF no-no's, you can use any radio in an ultralight. some just need more nurturing.


PostPosted: Mon Dec 31, 2007 1:46 pm
by lazairiii

What exactly is civvie impedances? Can you post a pic of the set up?


PostPosted: Mon Dec 31, 2007 7:19 pm
by JPXman
when i get a new camera i will - i lost it on xmas day somewhere after dinner outside!!!!

the gentex helmets (and any chopper helmet for that matter) use different impedances in the speakers and the microphone. what it all means is that if you try and use the helmet as-is with a civilian radio (like an Icom) the radio can't drive the speakers hard enough so barely any sound comes out, and the microphone doesn't match the radio's input impedance, so it can't drive the radios' modulator properly - so barely anything gets transmitted.

all i did was swap out the two speakers in the cups with ones from an old aviation headset, and got new david clark microphones (pricy). the wiring is fine as is, but i had to adapt it from the one plug "helicopter plug" to the icom that expects standard two-plug system. and all that entails is chopping the end off the icom adapter and buying a $10 helicopter plug female end and wiring it up.

i never thought that people might want to do this - so if anyone is having comm trouble let me know, it used to be my cup of tea long long ago, in a galaxy far far away.


PostPosted: Mon Dec 31, 2007 11:38 pm
by uscgairdale

For the navcom you won't need another antenna. The com vs. navcom thing is just a matter of preference. The general aviation pilots like the navcom as a backup just in case they need it. Personaly I just have a com because I don't have a need for the nav side of things in my it's cheaper. OK, I confess I guess I'm just cheap!

I own a JRC JHP500 handheld. Like you I picked up my radio used off of ebay and I've been very satisfied with it on several different ultralights. (Lazairs, Quicksilvers, a Pterodactyl, and a Kolb). The quality of the radio is a factor, but far and away the best thing to do is to properly shield all of your ignition system and ensure that your remote antenna is a good distance away from your engines. Take the time to set up this stuff right and it will definitely pay off in the end.