[TowerTalk] Capacitor to Tune 160M Vertical

Jim Brown jim at audiosystemsgroup.com
Tue Nov 27 15:31:32 EST 2007


Crew,

I'm thinking of following N6LF's advice on a rebuild of my 160 
vertical by tuning it low and adding series capacitance to tune out 
the resistance to match it to 50 ohms. I also hope to make it a bit 
longer. Legal power will put about 220VAC across 2.2 nF, at a 
little less than 6A. I think my greatest concern is dissipation 
from the ESR of the cap. Once I get this working, I'll probably do 
something similar for 80M.

My question is about what capacitors will work. I'm looking for 
about 2.2 nF (2,200 pF), and I'll run legal power with the fairly 
high duty cycle of a contest. I've got a selection of 3kV and 6kV 
caps in the 100-500 pF range, and 400VDC caps in the 10-100 nF 
range. I could series the LV caps or parallel the HV caps. Should I 
be looking at others? Does anyone have experience or an educated 
guess about which capacitor types are likely to work?   

73,

Jim K9YC






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