Interesting questions John.
First, let me say that I built a 2L 40M Delta Loop suspended from
a 20 ft boom attached to the side of a tower at the 120 ft level. The
horizontal (bottom) side of the loops were at 80 ft. I used 1/8 inch
nylon ropes to pull out the bottomcorners. To simplify installation
and service, I placed pulleys at each end of the boom and ran a
continuous loop of 1/4 inch rope. This allowed me to attach the
loops at the tower and pull them out to the ends.
The antenna was a KILLER to Europe, Africa, the Middle East, and
Indian Ocean, aimed at 60 degrees. I lost it, and every wire antenna
on the place, after 8 years of excellent service when a small tornado
or downburst knocked over dozens of trees in my yard and woods,
falling on every antenna tie rope.
I now use a 2L Cushcraft 40M beam, tuned to the CW dimensions,
on a different tower at 95 ft. I am quite pleased with this antenna
on CW but it is clearly not as competetive on SSB as the Delta Loop was.
The 8 ft wide tower you describe may have more of an effect than my
15 inch wide tower. It may be beneficial in your case to put the boom
on a mast 10 to 20 ft above the tower.
It is always nice to be able to rotate your 40M beam so you may want to
think about a "shorty-forty". The heavy duty Cuchcraft looks like a good
choice.
You can make the 2L Delta loop reversible by feeding each loop
with 3/8 WL of coax and switching BOTH sides of the feedline.
The unterminated feedline will look like an inductor at the feedpoint,
causing the non-fed element to look like a reflector.
GO FOR IT !
Let us know how it plays.
73 / GL, Tom N4KG
On Sun, 14 Feb 1999 19:55:08 -0600 "John T. Duncan" <jduncan@nol.net>
writes:
>
>I have access to a 90 foot tower and want to hang a fixed 2 el quad
>for =
>40m. The thought was to put a 20 to 24ft boom across top and using =
>ropes fashion a quad. The problem is that the tower is 8 ft across
>and =
>I would like thoughts on whether the quad would "see" all that metal!
>=
>Am I wasting my time? Any help would be appreciated.
>
>John
>
___________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
or call Juno at (800) 654-JUNO [654-5866]
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|