TopBand: Prevailing angles of propagation

[K3BU@aol.com]

There seem to be desire to get the lowest possible angle of radiation from
the antennas in hope of achieving super DX signal performance. This is
probably fuelled by the experiences on higher bands, like from 20m up where
typically lower angle means better DX performance. As numerous propagation
studies show, with decreasing frequency, there seem to be increase in
PREVAILING propagation angles. Let's not forget that antenna should match the
desired propagation modes. 
    I remember VE3NE, Bud telling us about experiment on 2m where they tried
different mobile antennas in the fringe area and the .25 wave vertical beat
5/8 and others, because it performed better at the existing angle of
propagation. I have verified that later on comparing 5/8 over 1/4 collinear
antennas with plain 1/4 wave whip, and since that time no more "fancy"
antennas on 2m mobile here.
    Also experience during my last operation in 1986 from portable site in
VE3 during 160m contest: I strang 1600 ft Beverages on gently sloping hill.
First night my inv.Vee and Slopers were outhearing the Beverages. Second
night I cut the suckers in half and voila! 160m sounded like 20 with Eus
booming in, killing the other antennas.
    Another experience was 160 m CQ CW from Cape Henlopen, DE. Winds
outwrestled me and my baloon verticals, not wanting to pack in and admit
defeat, I rewired the two elevated radials as an Inv. Vee with apex at 30 ft,
sitting at the edge of the small bluff over the ocean, I was surprised that
just about every station I called, came back and antenna was quiet on
receive. Brief attempt to get the balloon vertical up again brought in
horrible static crashes. Back to radials and I was able to hear and work the
stuff again.
    So dont get too hypnotised with lower is better, what is better is what
gets more signal into the layer (or mirror for those believing in mirrors) of
prevailing or desired angle of propagation. Beware of "reciprocity" between
transmit and receive, I found more disagreement, than agreement. More
antennas you have, more test comparing RX and TX reports you do, more you
see. You would also find that various antennas would perform better at
different times. The morale is: You never have enough antennas, especially in
the contest.
73 de Yuri, K3BU, VE3BMV

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