On Thu, 19 Mar 1998 18:28:56 +0000 "Alex C.J. van Eijk" <DXIS@wxs.nl>
writes:
>I am wondering how a half-sloper for 80m suspended from a 25m high
>tower
>effects the shunt-fed operation of that same tower for 160m, and
>vice-versa? Didn't find anything in the various books I have on the
>shunt-feed method.
>
>73 Alex PA3DZN
Alex; my own experience is that any interaction is minimal or unoticed
as long as the tower and/or guy wires are not naturally resonant on
either band.
I had a 30M shunt fed tower for 160 at a prior QTH and had no problem
with various 80M antennas such as 3 half wave slopers that I could drive
any adjacent pair in phase. Everything tuned up and lengths were as
expected.
I would suggest that the 80M coax be taped off to the tower at numerous
points and also decouple the feedline with ferrite beads where it leaves
the tower. I had to do that to eliminate meter fluctuation on the
Tailtwister rotator that turned 10-20M yagis on the same tower.
This is a very simplistic reply and I suspect that conditions vary among
users.
73 Carl KM1H
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