Hi
I see a number of messages regarding installation of antennas
(aerials) which indicate only a slight understanding of how they work. Most
VHF sets use a 1/4wavelength vertical antenna. If remote, this antenna
requires a groundplane which allows it full output if sized to agree with
the 50ohms in the coax cable. This size is 5% larger than the antenna pole
and can be as simple as two or three wires at equidistant angles to each
other. The handhelds have nothing like this antenna, and are particular to
the handheld itself - they are a different animal. It's true that without a
groundplane the signal will spill out, but most of it is swamped by imporper
impedance - and ELTs are insufficient enough without stifling the signal
further. If the ELT has provision for an antenna on its body, keep it there
and mount it where the antenna is relatively clear of large metal bits.
Connect a remote antenna incorrectly and kiss goodbye to 90% of the vital
message it may need to send one day.
Or contact a nearby ham of 30 years experience for a useful
word.
Cheers, Ferg VE3LVO
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