Dale, It is not a Bozo idea at all!!
At the top of my 134 foot tower, I run the coax for the 10M Beam, 40M
beam and 80 M rotatable dipole inside the 18 ft mast, out the top of the
mast, and attach them to a 1 foot extension angle bracket mounted on the
mast, down the outside of the mast to the three antennas, two mounted on
the mast and one on a ringrotor. Also in this coax bundle is a 4
conductor cable which controls the relays for the 80 M dipole (Force12
The angle bracket at the top is there so that the coax does not scrape
(chaf) on the steel mast during rotation. Instead, the coax/control
cable bundle being attached to the bracket which is attached to the mast,
turns with the mast and, because of the length of cable used (18 ft
inside the mast and another 20 feet below the bottom of the mast which
allows me to lower the mast for access to the upper antennas) it gently
twists over the 38 feet of cable without any damage. Note that there is
no chaffing at the bottom of the mast since the additional 20 feet of
cable/coax drops straight out of the mast, all inside the tower until it
reaches its first tie-off point on the tower some 20-22 feet below the
bottom of the mast..
Why did I do this in the first place? Because my tower is 24 inches/face
triangular, guyed inches below the ringrotor mounted at the top of the
tower. It would be extremely difficult and very unreliable to feed the
40M beam in the ringrotor cradle otherwise. BTW, the mast is turned by
using a mast-twister attached to the ringrotor.
Check out my homepage for fotos and more details:
Dale L. Martin wrote:
> Okay, Steve, you can tell I'm in a Bozo mood tonight....
> What about this:
> Run the coax up the bottom and out the top of the mast and down
> to the antenna? With the appropriate means to prevent chaffing
> at the top and bottom of the mast, of course. The loop out and
> down would look strange as heck, but what the heck! We're hams,
> after-all....we're supposed to be "strange."
> Or maybe use right-angles and a barrel at the top to cut down the
> 'loopy' look.
> dale, kg5u
> FAQ on WWW: http://www.contesting.com/towertalkfaq.html
> Submissions: firstname.lastname@example.org
> Administrative requests: towertalk-REQUEST@contesting.com
> Problems: email@example.com
> Search: http://www.contesting.com/km9p/search.htm
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Administrative requests: towertalk-REQUEST@contesting.com