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ELT antenna for com 2

MConner

Well Known Member
My ELT antenna is mounted in the baggage compartment with the base at the top longeron and extending upwards in the fiberglass top. For length, it bends toward the center of the roof with about 1/2 of it mostly vertical.

I am adding a #2 comm radio and am thinking this type of antenna install might work since most of what I use it for is receive.

Anyone tried an ELT antenna for comm? Should be close as 121.5 is in the comm band.

Mark
 
Just a comment. Your mounting location provides a very much less than ideal ground plane, with virtually no ground plane extending to the outboard side. For 1/4 wavelength antennas like this the ground plane is part of the system.
Having the top half of the antenna horizontal is not a huge deal (might cost you 10%?).
 
Another small point; the diameter of the antenna affects bandwidth. The ELT antenna is small in diameter and therefore has very little bandwidth.
i.e. The further you get away from 121.5 Mhz., the less the gain of the antenna.

Bottom line; Not a very good idea.
 
Ok tried it

tried the ELT antenna in the baggage area for com 2. Receive Works at about 85% as well as com 1 to the front, seems a little weak to stations behind me. Transmitter was reported 5 x 5 by ATC 40 miles in front. Have not tried behind. Think it is due to ground plane efficiency.

Have not tried all frequencies yet.

Mark
 
If your ELT antenna is one that has a "lump" in it, this is often a tuning device which helps the antenna radiate not only on 121.5 but also on 243.0 MHz. With this being the case, use of these antennas for COMM operations is not a good idea. If you really want a 2nd COMM, install a 2nd COMM antenna.
 
Com 2 is there for a back up similar to carrying a hand held. It is nice to be able to listen to an ATIS or monitor a CTAF while still talking to ATC on com 1. The transmitter works better than a hand held in case com 1 fails. No holes in the plane and no drag from the antenna. The ELT antenna was surplus so saved a few dollars. I am happy.

Mark
 
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