On Sunday I increased the inductance at the top of my mast. I
replaced 3mH of Litz wire with 7mH of ordinary wire. This made the
antenna almost self-resonant. In fact, I needed a 6800pF capacitor
(very heavy duty oil-filled, from the Puckeridge Decca site) in series
with my 0.5mH variometer to tune it.
As expected, the current dropped - from 2.7A to 2.2A - as the point
of maximum current went higher up the mast.
There have been no measurements yet, but initial results seem
good. I received the best ever reports from GW (599), GM (589)
and SM (579), and worked DJ9IE (559) who had never replied to
my calls before.
An all-night transmission using 30s dots on 135.9235kHz did not
seem to cause any trouble, so all seems stable.
Mike, G3XDV (IO91VT)
http://www.lf.thersgb.net
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