kinda at a loss... I just don't see how my old sloper would
be melting its end insulator when I'm using the new
sloper!>>
Dave,
The problem with 1/4 wl slopers is they are sloppy antennas.
They should be called sloppers, not slopers. They work
mostly by sloppy luck, not good design.
They use the tower as a ground, and the electrical rule is
the tower and coax shield has the same current flowing into
it at the feedpoint attachment point as there is flowing
into what we think is the antenna. If you have three amps
flowing into the slopper, you have 3 amps leaving the coax
shield attachment point and that current has to terminate
somewhere!
Everything else on the tower is excited with RF, and some
things (depending on length and distributed impedance) can
even have more voltage or current than the slopper you are
thinking is the antenna! That's right, it's possible to have
5 amps or more in the tower or wirings on the tower
someplace away from the slopper with one amp into the
antenna! It's also possible to have more voltage at the open
end of some wire handing off the tower than you have in the
slopper you are feeding.
You can be sure you have large standing waves on the
"unused" slopper, and those standing waves are causing a
very high peak voltage at the slopper end. Enough voltage to
melt ropes and burn insulators means you have the start of a
very nice Christmas display. Put a wire brush at the end,
and make a nice star!
BTW you can burn up rotors, antenna switches and other
things if you are unlucky and excite the control cables with
voltages and currents like that. I'd just put up an Inverted
V dipole, and be done with it. Or do something else less
risky.
73 Tom
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