In a message dated 97-11-11 03:50:59 EST, NI6T writes:
<< For example, VK0IR was noted on
the west coast as coming in from the west or even more northerly, on
both 80 and 160, although its SP direction was SSW. The sidelobe
response of a Beverage to horizontal polarization may well explain why
received signals here have often appeared to be coming from widely
skewed directions. >>
Not so!
Skewed path is due to propagation being better, or pulled towards the equator
(solar) as a result of better ducting properties closer to current solar
equator. Usually happens at the beginning of the opening. This can be
observed on other bands, I have seen it happening regularly on 40 m while
using stretched full size Telrex beam, no confusion there with "other
polarization coming from another angle".
Besides, side lobes of the other polarization are way down to be
significantly usefull.
We have more variation with elevation or vertical angle of signals, and that
being different at both ends of the "duct". Grey line propagation tends have
more uniform and favourable angles.
Don't forget slow polarity rotation of signals on 160, sometimes it might be
required to wait few minutes for polarization to "come back" in order to hear
that marginal signal again. This is where every 0.5 dB counts!
Yuri Blanarovich
K3BU, VE3BMV, P40A
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Problems: owner-topband@contesting.com
|