[Antennas] top hat for vertical

Fri Dec 31 09:30:32 EST 2004

DavidE Benedict wrote:
>> Maybe use a plastic guy-ring (or some other structural-type insulator
> material) at your 13 foot level, and place the top-hat at the top as would
> be best. The guy-ring wouldn't have to be more than 4-6 inches or so in
> diameter.
>
That is certainly a possibility. I used to use wire rope for guying my
tower. Some years ago I ran some calculations to see what would be the
optimum segmentation of the wire rope guys to reduce resonance effects
across the HF bands. Turned out that I needed to add a whole mess of
insulators and clamps to get the segments short enough to eliminate
resonance effects across the entire range.
After figuring up the cost of adding all that hardware, it came to more
than the cost of replacing the wire rope with phillistran. So now I use
phillystran for guying. Phillistran is jacketed kevlar fiber rope. It
is non-conductive and extremely strong. Been using it now for over 10
years on the tower installation.
I am figuring on using some lower cost, lighter weight phillystran for
guying the vertical.
I have also given up trying to top load the thing. No need for that
since there is enough tubing length to be a full quarter wavelength on
30 meters. I am also going to try using it as an inverted-L by running
a horizontal wire from the top of the vertical to a second support mast.
With the open wire line and the ballanced antenna tuner I am hoping the
thing will serve as a reasonable all-band antenna. Primarily 30 meters
and up but I expect it will also work, at reduced efficiency, on 80 and
40 meters.
Regards,
Frank Kamp
K5DKZ