On 9/16/2010 7:41 AM, Bill Ogden wrote:
I have a half-sloper attached to my tower. It is mostly used for 80 meters
(but also for 160 and 40 in rare cases). It is attached to the top of the
middle section of a 55' crankup tower. The tower has a number coax and other
control lines suspended a foot or so outside the tower. I am in the "far
suburbs" but 40/80/160 still have more noise that I hoped and I suspect some
of the noise is from the neighborhood; there is no specific noise generator
that I can detect.

Question: would a coax choke (5 43-material toroids with 5 loops of coax) at
the feedpoint of the half-sloper do any good? I am a little confused since
the tower (and, I assume, the outside of the coax) is an intentional part of
a half-sloper antenna.

At the bottom of the tower, the coax goes underground for about 50' to the
rig.

Bill - W2WO

Might, actually, be better to feed the other end of the sloper, bringing
that end as close to the shack as possible, shortening the coax and
dropping out the associated loss, possibly having a favorable effect on
your noise, etc.

Of course the addition of a suitable counterpoise(s) would be necessary
.... just a thought ... and, of course, a notable amount of work.

Regards,
JS