On Fri, 10 Sep 2004 23:18:13 GMT, "Dale Parfitt" wrote:


"Walter Maxwell" wrote in message
.. .
On Fri, 10 Sep 2004 13:38:34 -0500, "Steve Nosko"
wrote:

When you are BETWEEN markets, this is common. Or, if you want to
listen
to a distant station and the wrong one is close. I'm equi-distant from
Chicago, Milwaukee and Rockford and have this problem hearing WDCB 90.9,
west of CHi-town with WHAD 90.7, S-W of Milwaukee pounding in. They're
in
different markets.

This was discussed not to long ago here. A notch in the antenna
pattern
is not too difficult. Two vertical dipoles spaced (about) a half wave
and
fed with the proper feed line so they are 180 degrees out from each
other,
can make a nice null - actually two. They are perpendicular to the plane
of
the antennas. I'd have to sit and tinker to remember the feed system,
but
there has to be 1/2 wave more feed line in one dipole, compared to the
other.
It is also possible to do the same thing and get a one notch pattern
(cardioid). If I recall, the antennas are spaced 1/4 wave apart and the
feed is 3/4 wave of feed line between them. Again, the receiver simply
connects to one of them and the null is off one end.

Yeah, Steve, but isn't FM broadcast wirh horizontal polarfization? With
vertical
dipoles the only signal you'll receive is from reflect;ions off objects
such as
buildings. What kind of reflection coefficient would one expect ? Enough
for a
good signal?

Walt

To the best of my knowledge- commercial FM broadcast has transmitted on both
V and H for many years- how else would a vertical whip on an automobile
receive FM?

Dale W4OP

You're right, Dale, my age and ignorance are showing.

Walt