Topband: receiving antennas

[Bill Hohnstein]

W8JI wrote:
> One problem with Eznec is it doesn't plot groundwave. That means 
> low angle patterns are not correct, a very critical part of the 
> antenna response for people who have local noise sources is 
> missing!

My number isn't a good one to use for reducing a point source
of noise.  Due to surrounding objects, the exact depth and azimuth
of a particular null (to minimize a point source noise) can be
inexact via antenna modeling.  Computer modeling is a good
place to start with actual "antenna tuning" to maximize the null.
I think that my number would be also representative of the noise
reduction capability to a wide angle source of ground wave
noise.  While the ground wave vs sky wave nulls might not
be at precisely the same azimuth, the pattern "quality" of
both are similar.  That would result in comparable wide angle
noise immunity.
For myself, 99% of the time (even in the heart of winter), my
receive limiting factor is static.  Narrow null antennas rarely do
me any good in reducing that.
Perhaps a precisely accurate number for comparing all different
types of antennas off-lobe wide angle noise reduction is impossible,
I found my number useful in improving specific antennas.

73,  Bill     K0HA


--
FAQ on WWW:               http://www.contesting.com/FAQ/topband
Submissions:              topband@contesting.com
Administrative requests:  topband-REQUEST@contesting.com
Problems:                 owner-topband@contesting.com