[TowerTalk] 75M rotatable dipoles

[GALE STEWARD]

Jerry,

I'd put a 40 at the top and use a sloper or a wire
vertical for 80 (if you're interested in DX).  Just
for grins, I modeled a 80 meter dipole with 1.5 in.
dia. elements at 92 ft. (freq 3.8 mhz).  Over average
ground it shows a maximum gain of 6.54 dBi at an
elevation angle of 42 deg.  The azimuth plot at this
same 42 deg. shows that the F/S ratio is only 5 dB. 
I've used an 80M inverted vee at 100 ft that worked
pretty well but was no match for a single vertical
(full size) even for the "close" DX.  A vertically
polarized loop (triangle) for 80 might work well off
of a tower at your height.

GL & 73,
Stew  K3ND

 
--- "J. Kincade" <w5kp@swbell.net> wrote:
> 
> Is a 75M rotatable dipole a waste of money if 92' is
> as high as one can
> install it? Would having it that low destroy the
> rotating advantage of the
> end nulls, thereby turning it into an expensive
> inverted V?  The
> alternative, of course, is to spend the bucks on a
> shorty 40 at the 92'
> point instead, and hang a good 'ol cheap inverted V
> for 75.
> 
> Thanks for the brain cell time.
> 
> 73, Jerry W5KP


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