Date: Thu, 12 Dec 2002 06:33:21 -0500
From: MarkusVester@aol.com
To: rsgb_lf_group@blacksheep.org
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Subject: LF: Antenna tests
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Hi Alan and group,

thanks for the fb report and pics about my tests and QSO with OH1BS on 137.0kHz yesterday night.

Though I normaly really dislike the cold weather (as does my 17-year-old Golf Diesel which is supposed to take me to work), the one good thing about frost is the improving LF-antenna performance. Series loss resistance goes down by 1 to 2dB, and surprisingly, in addition to that I seem to get another 1dB from increased effective antenna height, as measured by comparing received voltage against a non-resonant loop. There are a few high fir trees in the vicinity of the aerial, and I assume that under heavy frost, the shunt conductance of the trunks falls below the capacity of the tree crowns, so that electrostatic shielding is significantly reduced.

In yesterday's tests, I got up to 2.7A into the 220pF top load from 160W, but visible corona appeared at the ends of the thin wires (two parallel lines of 0.5mm enameled copper having U-shaped end connections). After adding extra short pieces of crosswire at the end of the leg that was most affected, I can now safely run 2.5A (about 13kVeff).

Still amazed that Peter manages to get up more than 4A at 73kHz ;-)

73 es all the best
Markus