On Fri,2/13/2015 12:29 PM, Grant Saviers wrote:
At TX5D (FO-A), I was able to instant A/B a 15m vertical (two elevated
radials) at high tide line vs a crankIR tuned on 15m about 70' from
high tide. US stations (5k to 7k km) reported 1 to 2 S unit
improvements with the antenna nearer to the lagoon salt water.
Received signals were at least that much improved.
What radial system did the Crank-IR have? The version that they demo
has only one. That could account for at least part of the difference. A
greenhorn DX trip used one or more of these antennas, and they were
piss-weak.
The nature of the earth under a vertical has a strong impact on its
EFFICIENCY -- that is, it burns some the TX power, so that fraction is
not radiated, thus never sees the earth in the FAR field, nor does it
excite skywave. It is this loss in the earth under the antenna that a
radial system reduces. While I'm sure that many of our readers are aware
of this, many may not be.
73, Jim K9YC
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