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Old July 29th 06, 05:57 AM posted to rec.radio.amateur.antenna
Sal M. Onella Sal M. Onella is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 442
Default Aluminum tubing for vertical antenna


"Hank Zoeller" wrote in message
...
Hello everyone,

I'm contemplating putting up a vertical antenna for HF use. I'm looking
at an approximate height of 30 feet or so. I am thinking of using
aluminum tubing (0.058" wall) in a 'telescoping' manner. Here are my
questions (so far):

1) Diameter. For wind resistance, should I start with something like 1
inch diameter and work down to 3/8 inch? Would the antenna be stronger
if I started with 2 inch diameter and worked down to 1-3/8 inch?

It would seem to me that the larger diameter might be better able to
withstand wind but it would also offer more resistance to wind possibly
negating the additional strength. But, I have no experience to draw
from. So, fat or slim?

2) I am planning a set of guy ropes at about the 12 foot level, a bit
over 1/3 height. Is there a better height for guy ropes? I can put as
much concrete in the ground as I like, and a very robust mount system is
possible. Is there any way to make an unguyed 30 footer that isn't a
tower form factor? Something like making the bottom 12 feet or so from
2 inch diameter, 1/4 inch wall tubing and then light weight tubing from
there up to full height?
--
73, Hank


http://www.valcom.ca/Guelph/products...b-u_photo.html This is
built for navy shipboard use so it may be "scary expensive." These are
virtually indestructible. You have to hit one with a crane boom to break
it. It is exactly what you described in your last paragraph. This size
whip covers 2 - 30 MHz with a tuner.

The Navy has used many 35-foot whips over the years. There were
five-section versions, but any you found now would probably be too corroded
to be of use.