"" A similar observation was made 20 years ago by Brian Beezley, K6STI, in a
QST article titled "A Receiving Antenna that Rejects Local Noise"
(September, 1995, page 33): I've been looking around for something that
might work better than my present antenna, and I see good reports about the
Waller flag from people who are actually using it. So I'll give it a try
and see how well the theory matches up with actual practice. That's what
ham radio is all about -- no? >>>>
Here one of the last understood subject on radio and antenna work, most of
all paper about antenna. RF and propagation on MF and low band are valid
only for vertical signals.
For horizontal signal there is a major difference in the way Fields interact
with Matter. If are an Engineer or someone that wants to give a try I
recommend the book Electromagnetic Waves and Radiation Systems Edward C
Jordan and Keith G Balmain page 277 Chapter 9 and 372 Chapter 11 Antenna
fundaments.
There is no horizontal signal near the ground, there is no ground waive or
surface waive near the ground. So any or all manmade noise only can
propagate by vertical surface waive or ground waive.
Increasing the directivity of the RX antenna you can increase signal do
noise ration my the same directivity gain. However is you turn the antenna
horizontal the attenuation on vertical propagated noises is huge!.
A low dipole on 160m,as example, does not receive any horizontal signal!,
the only useful signal arrives vertical in the direction of the wire, same
case of beverage antenna.
Check the excellent article by Kai KE4PT on QEX and QST about best high for
horizontal antennas. You will see that near the ground the attenuating is
severe near 4 decay's.
http://www.arrl.org/files/file/QEX_Next_Issue/May-Jun_2011/QEX_5_11_Siwiak.p
df
Using the antenna as polarization filter is the only solution to increase
signal do noise ratio in urban areas.
PY2XB lives downtown S Paulo, Fred is using WF for low bands and when he
detunes his inverted V the noise on the WF drops 2S unis on 80m.
Tom is right about the 40 db gain, gain means nothing, the NF of the system
is the only thing the matters.
Decrease your RF gain and increase the AF gain that you will hear better
than most preamp's can help.
N4IS
JC
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