Tom
'>>
The way I see it is if the rate is not 0.546 uS or so, you do not have
circular polarization.You have a slowly rotating wave, and the sense of the
RX antenna would be meaningless unless you could time-sync rotation at that
slow fading rate.
Someone correct me if I am wrong.
<<
100% correct
My system has two WF's, same gain, one vertical and another horizontal,
feeding two preamps into IC7800 two receivers. When there is fading on the
signal E-W, the time of the rotation from H to V could be long as 5 minutes,
most of the time between 1 to 2 minutes. Using M=S on the IC7800 I can keep
the two receivers at same frequency, and I can hear one receiver on each
ear. I used to QSO Raoul ZS1REC during summer time and sometimes we start
the QSO using V pol and finished on H pol..
About the signal noise gain using H and V with two identical receivers, I
can say there is no gain at all, when the signal is weak, I switch the other
antenna off and hear with only one channel. The advantage to have both is
just to avoid listening in the wrong antenna listening on both antennas at
the same time. It is not diversity eider because my antennas are only 60 ft.
apart .
Besides E-W when the signal is coming from less 45 degree and it is
fading, I never see rotation, the vertical signal can have a deep QSB and
the horizontal signal constant with no QSB. That just happened last Saturday
with the FT5ZM, the horizontal signal was solid all the time with no
variation on the intensity, however the vertical signal had deep and fast
QSB.
My take on that is the propagation mode or multi-path, signals can arrive
from a refraction out of a duct and or from the same direction but from a
different region on the ionosphere. There is no real correlation between the
two polarizations signals, in practice they don't mix. It is very different
from HF or VHF where the wave is always coming from the same media.
Another point is that refraction increase with the decrease square of the
in frequency, on 160m the refraction is stronger than 80 or up, as a result
it is not necessary to transmit a horizontal signal to answer a horizontal
polarized income signal. When the TX signal reach the first refraction point
the wave split in two one vertical and another horizontal. What means is the
efficiency to couple the TX signal with the atmosphere this is more
important than the polarization itself, but 160m only, moving up in
frequency the results are completely different, and 30 MHz to 50 MHz it is
even special because it is transition from HF to VHF propagation mode. The
experiments on 28 MHz does not apply to 1.8 MHz.
Between 1 and 2 MHz , everything is different from HF or VHF
Regards
JC
N4IS
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