[TowerTalk] Was Radials... 160m High angle vs. low angle
btippett at alum.mit.edu
Sat Jun 17 07:18:46 EDT 2006
>Having a 160m inverted vee with the apex at 60' is like having
a 10m inverted vee with the apex at 4'. It's a cloud burner.
A 160m dipole at 100' is a LOW antenna.
But that's exactly what you need under
certain conditions. In addition to being good
for local (<300 mile) contacts, sometimes TOAs
go extremely high for DX. Typically this is
at sunrise, sunset or in geomagnetic disturbances.
>That said, there ARE high angle nights on 160, but it's my
impression that means signals arriving around 25-30 degrees,
rather than 8-10 degrees above the horizon. It certainly
doesn't mean arrival angles above 60 degrees, which is what
such a low antenna will produce.
Normally my 3-element vertical (black plot) is
about +10 dB better than the inverted-V (blue plot).
However, it can sometimes be the other way around.
Looking at the graph, I would think "normal" is
about 10-15 degrees TOA (where the black plot is
+10 dB vs the blue). However the case where the
inverted-V is +10 dB indicates a TOA of 70 degrees
I had both a vertical and inverted-V in Colorado
for many years. I finally put up an inverted-V here
in 2004 and only wish I did it sooner. Sometimes
the difference is incredible. And BTW, TOAs also
apply to receive antennas. Beverages do not work in
high angle conditions (often a clue that high angles
are predominating) so I transmit AND listen on the
inverted-V in those conditions.
73, Bill W4ZV
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