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:[email protected]] 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 _________________ Topband Reflector Archives - http://www.contesting.com/_topband --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _________________ Topband Reflector Archives - http://www.contesting.com/_topband
