[Antennas] Need antenna info
Sandy and Kees Talen
[email protected]
Sat, 26 Jan 2002 21:01:03 -0600
Hi Bob, WA2HOQrp <tm>.......2 week old EXTRA
...........First, congratulations ! Second, there are
people running around on the roof all the way to the
edge ? or is that just to protect maintenance people ?
My 2 cents worth.......
If you don't want or they won't allow a beam/tower/rotor,
and you can't get the proper radials for a vertical since
this appears to be a roof location, and you don't have to
"hide" the antenna (like #26 wire)......... the best all around
antenna I have used for many years, is an inverted "V"
trap dipole. There are instructions in all the ARRL handbooks.
The traps allow loading and operation on all the bands
from 80m to 10m. Coax can be the smaller foam core
RG58AU if you can't run the larger RG8 under the rocks.
That is all 50 ohm cable which matches well to the inverted
"V". Its called an inverted "V" because the pole at high point
is in the middle with the ends tied to other supports. Try to
get the middle and the ends in the same plane and running
North-South so the lobes go East-West (or whatever direction
you prefer to opptimize).
If you have to bend it 30 degrees or so that's OK. If the angle
from the center down, on one side is different than the angle
on the other side, that's OK. Make the design with wire that
is a little long (just twist the extra back onto the antenna) so
you can add/subtract length later as you optimize it (you don't
want to have to splice the antenna later to add length). Get/borrow
an SWR bridge and use this for optimizing the antenna. Use
ceramic insulators as #1 choice, plastics as #2.
You probably won't need it, but It's always a good idea to use
an antenna tuner at the radio.
Nothing fancy, just the basics. There are also several commercial
wire antennas available.
73s Kees K5BCQ