N7NEU wrote:
>What do y'all think of putting a vertical antenna on top of a tower
>that has a tri-band beam presently installed. I am thinking possibly of a
>Butternut HF2 for 7 and 3.5 mhz. Mainly want to cover 7 mhz, but 3.5 would
>be a bonus. I mainly work the domestic contests and do get on and play in
>the occasional dx test as well.
Craig
The butternut manual "warns" against the type of installation you are
contemplating...but what the heck..nothing ventured nothing gained.
Try it without any ground counterpoise at first (ie the Tower/beam is the
ground counterpoise. If this doesn't work then try one resonant radial
(for each band)insulated from the tower. Try using insulated wire
and those old 300 ohm TV ribbon standoffs to keep the "resonant"
radial away from the tower a bit. Expect to have to play with the lengths
of these radials quite a bit as the tower will "load" them (I suspect
they will be shorter than "formula")
I can even envision using three 300ohm TV ribbons (one on each leg), with
one side of the twin lead cut for 40M and the other cut for 80 (and maybe
one cut for 75). You might want to also think about putting a relay up
in the 80M coil so you can "automatically" short out a few turns then
you can work CW and SSB just by flipping a switch. (I'm surprised the guys
a B'nut dont offer this as an option....hello anybody listening over there).
You will probably get to climb the tower about 2 dozen times before you get
it all perfect..but what the heck... we all need the execise...
Let me know what happens!!
Dave
N0DH/7
Spokane, WA
n0dh@comtch.iea.com
|