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Old September 24th 12, 09:39 PM posted to rec.radio.amateur.antenna
Dave Platt Dave Platt is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 464
Default Home made antenna question??

I thought of that but there are a bunch of other things on there like TV
antennas, dishes, clothes lines, back yard lights, etc etc. Stunt it, just
wanted to throw up a crazy idea, I know it is a very broad question. What is
the smallest thing I could use with a pretty good tuner? On top the utility
tower?


How about a car/truck "screwdriver" antenna?

I have a pretty good tuner and will use the tuner to tune.


The combination of a short vertical, a tuner in the shack, and a coax
feed, is not a particularly happy one.

You *may* be able to tune it, in the sense of presenting a load to
your transceiver which won't cause its output section to complain or
leak blue smoke. However, the losses in the tuner, and (particularly)
in the coax feedline, are likely to be very high... you won't get
much signal out, and you may end up with high enough voltages on some
sections of your coaxial feedline to cause arcing (even at "barefoot"
power levels!)

So, the two approaches I can think of which might work would be:

(1) A "screwdriver" antenna or equivalent... a vertical whip (longer
is better) and a remotely-adjustable loading coil.

(2) A vertical whip, and a remote-controlled (or self-controlled)
antenna tuner / transmatch mounted right at the base of the whip.

In either case, you'll probably need to use the tower itself as the
"ground" (counterpoise) for the tuned antenna... plan on running some
heavy, low-impedance braid from the tuner to the antenna mount point.

--
Dave Platt AE6EO
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