[TowerTalk] Single Wire Antenna? de K0FF

[K0FF]

How about a single feedline, and single tree for support? 66 feet up, 70 or
so feet out, looks like an inverted L.
One 160 there is a coax-cable trap at the peak. This splits the antenna for
160/75. A small coil at the bottom brings it down to 80, and is shorted out
with a switch for 75 (sorry not automatic- use a ceramic fuseblock and piece
of copper pipe for the switch). for 40M, run another wire up from the same
feedpoint 33 feet. It is held away from the main wire with rings cut from 4"
PVC drain pipe. Small holes drilled every 90 degrees around the
circumference of the ring. Wires tie-wrapped to the rings through those
holes/  40M wire works as 3/4 wave on 15 too. 30M- ditto with a full size
wire.  You can use the 4th set of holes for certain other bands, but not all
will work with a single feedpoint like this. Keep the ends of the wires well
separated as very high voltages appear and will arc over, but the 4" tubing
is fine even for 1.5kW. Where each of the shorter wires stops, continue to
the peak with a nylon strip, birdcage fashion, so that the antenna is
balanced mechanically.
4 radials made from insulated wire tuned 1/4 wave for each band laid on top
of the ground.

No tuner needed.

Use a pulley on the peak, every tweak affects the other bands, and this
thing takes a while to tune up, but afterward, it's very broad across the
band, being essentially a natural resonant GP. The coaxial cable traps also
give the widest bandwidth of all the different types that I've tried.

What would you call this? A fanned vertical-inverted L Ground Plane maybe.

Anyhow it works great.

Geo>K0FF
-----Original Message-----
From: John Schaffner Jr. - K8LN <k8ln@neo.rr.com>
To: TowerTalk <towertalk@contesting.com>
Date: Thursday, June 22, 2000 5:15 PM
Subject: [TowerTalk] Single Wire Antenna?


>
>TT's
>
>Haven't been able to come up with single wire to operate 160/80/75/40. Been
>feeding 450 ohm ladder line to a vee'd dipole  (68 ft at apex) on 160.
>Can't find a sweet spot for all 3 bands.  Different lenghts will bring
about
>2 good tuneable bands but one always lacks. I am wanting to use this
antenna
>for DX contests.
>
>Any ideas?  What are other Single Wire contesters using?  And what tuner
are
>you using.
>
>Tnx
>K8LN
>John
>
>
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