For domenstic use, an 80M dipole at 50 ft will do well.
For DX, a vertical will do MUCH better. Unfortunately,
a 50 ft tower with a Yagi on top will act as a parasitic
REFLECTOR to a separate 80M vertical.
I had just such an arrangement at a previous QTH with
an 80M wire vertical suspended from an 80 ft tower.
To the east, about 50 ft, I had a TH3 on a separate 50 ft tower.
The vertical was a KILLER into the Pacific. It SUCKED to Africa
and Europe. I concluded that the TH3 Tower was acting as a
reflector.
There IS a solution. Use your 50 ft tower and Yagi as an elevated
GP or shunt feed the tower and install 30 or more ground radials.
See my article on Simple Effective Elevated GP Antennas in QST
for JUNE 1994 or any of the later ARRL Handbooks.
If you STILL want a separate 80M vertical, I highly recommend the
MFJ 1792 80 / 40 vertical. It is FULL SIZE on 40M with an isolating /
loading coil and a capacity hat at the top for 80M. It is rated at 1500W
on 40M and 1000W on 80M and very reasonably priced around $150.
Avoid BASE loaded verticals such as the HF2V or other Butternut
verticals which suffer from reduced efficiency and bandwidth on 80M.
The GAP verticals use a transformed capacitance to act as a series
inductance on the Lowest Band of operation which also reduces
efficiency and bandwidth.
Tom N4KG
On Sat, 18 Aug 2001 Tom Anderson <ww5l@gte.net> writes:
>
> After taking a lightnming hit I'm redoing the antenna configuration
> on my crank
> up tower. One question is does anyone know how efficient a
> shortened 80 meter
> dipole/inverted vee (80 ft) is versus the advertised "full size" 80m
> dipoles of
> 130 ft or so? The highest I can get the apex of the dipole/inverted
> vee is 50
> ft. (I have a TriEx WT51 with a Mosley Classic 33 WARC (the the 40m
> kit on the
> driven element) on top. The reason for investigating the shortened
> dipole/vee is
> my lot is just 100X150 Any help appreciated, or would I be doing
> better by
> putting up a vertical?
>
> Tom, WW5L
> Colleyville, Texas
>
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