Aluminum tubing for vertical antenna
I took scrap pieces of aluminum tubing lying around, not being particularly
careful of sizes as along they fit snugly into adjacent pieces when they
were slotted. I used hose clamps. I made it 33ft and 3 inches tall (1/4
wave on 40). It has 32 radials of various lengths for the non-WARC ham
bands 40 meters and higher. 16 of them are 34 feet long for 40. SWR on 40
meters is 1.2 to 1 without any adjustment at 7100. The vertical covers the
entire band. I use a Palstar AT1500CV transmatch on other bands and run 700
watts when needed. I can work anything I can hear and I work tons of DX.
The antenna is very quiet for a vertical. The Palstar has no problem
matching this vertical on all bands 40 through 6 meters including WARC
though 12 meters is the trickiest. Works much DX on all bands whenever I
try Peter I Island, Kiribati, etc., though I use other antennas on bands
other than 40 cut appropriately. Cost of the antenna was $0.00. I used
scrap tubing, scrap #12 or thicker radial wire, leftover rope for 3 guys at
18 feet, leftover 4BTV base. This antenna has been up for months on a hill
at 1100 feet and survived 80 mph plus gusts.
"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
|