Ok - so the goal here is to increase my competiveness for medium duty
contest
use. Primarily in domestic contests like Sweepstakes and the CQP. I am
near S.F. in 6-land.
My "main" antenna system will be stacked 4 element tri-banders at 75' and
50'. I will have a rotatable dipole for 40/80 at 85' on the same tower. I
want to add some kind of tri-band capable antenna for my second radio to
use.
Space is at a premium, this is a suburban 1/4 acre lot.
The easiest thing for me to do is to put up some kind of vertical. Since I
am worried about the front end of my second radio given that I don't have
lots of room (or money, for filters), a vertical seems like it would give me
the best receiver protection for the least effort. The base
would be about 15' up, the top can be maybe 45' up. The vertical would be
about 50' away from the tower if it is a dipole, probably 40' away if it
requires radials. The vertical will be to the south-west of the tower, a
direction that I pretty much never point the beams in. The U.S. is
east-north- east from here (about 70 degrees).
Seems like the obvious options are a tri-band (10,15,20 meter) vertical fan
dipole (not too much fan) or a tri-band 1/4 wave vertical with 3 or 4
elevated
resonant radials.
My gut and the computer both favour the vertical dipole, even if the 20
meter
radiator has to have its ends bent a bit (if I can't get 30' of vertical
space
in total).
Would anyone like to comment, or suggest an alternative that I haven't
considered?
Would anyone like to hazard a guess about the behaviour of my second radio's
receiver, when I am running full power into the stack of beams? Is 50' of
separation and vertical polarization going to be enough, or do I need some
kind of filter to protect the front end?
Thanks for your thoughts,
***dan
Dan Levin, N6BZA
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