Concerning an ELT antenna: I just used a length of prepared
coax, RG-58, BNC connector on one end end at least (e.g.,
allelectronics.com, cheap). Separate the shield and center
conductor for a length of exacty 21.5 inches, making a
dipole.
Now I may be cheap when it comes to antennas, especially for
worthless ELT unless you fly over really remote and harsh
terrain, but not when it comes to my MFJ-259B antenna
analyzer. Not particularly cheap, so I get some use out of
it. This kludge on an antenna checked out perfectly at
121.5.
Without a "balun," the feedline shield will radiate a bit.
MFJ-259B doesn't detect that. The mitigator is the fact
that a dipole, within five feet of the ground, will radiate
sharply upward, about 45-deg at least. A monopole whip
antenna on a flat ground plane won't quite do that for you.
That's likely to be the situation of the "crashed" fuselgage
w/r/t to earth.
In installing the coax antenna to the fuselage side, like
with RTV silicone, have the two poles about a 30-deg angle
---From vertical -- further fills in the natural void to
upstairs satellites or search planes, if the dipole legs
were in a straight line.
Reg,
Fred F.
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