Topband: Air wound coil

[Clive GM3POI]

Or better still, Shorten the L until it is self resonant  at 1.9mhz, thereby
lowering the amount of horizontal polarisation. Then use a simple hairpin
coil across the feedline typically around 5microhenries. This will then when
chosen correctly match at your chosen ideal spot say 1825.
And provide a DC short to ground for the antenna. No Caps needed.  73 Clive
GM3POI
 
-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Tom
Boucher
Sent: 02 September 2018 18:20
To: 160 reflector
Subject: Topband: Air wound coil

Bob W7RH - you don't need expensive hard-to-find vacuum capacitors to match
a quarter wave 'L' or 'T' on top band. I use cheap multilayer high voltage
disc ceramics and these have been working perfectly at QRO levels with my
inverted 'L' for years.
I use 1600pF made up from 1000pF + 470pF + 220pf all rated at 6.3KV and
available (over here) from CPC at less than $4 for 10.
Antenna is slightly longer than a quarter wave so it is inductive and the
capacitors form the other part of the L-match network.

73,
Tom G3OLB
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