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Topband: high SWR problem with RG214

Subject: Topband: high SWR problem with RG214
From: sasas asasas <>
Date: Thu, 21 Oct 2010 09:26:39 -0700 (PDT)
List-post: <">>
Hi. I have a transmitter 500w. I was operating my transmitter with low SWR 
(250w FWD power and 0,5w RFL power). The antenna's match system is only a 
series variable capacitor 0-500pf. With this variable capacitor i can achieve 
very low SWR.
My antenna (the feed point i mean) was starting inside the transmitter's metal 
house, and i have some problems with my pll's lock and the modulation. So i 
decide to move the antenna's feedpoint out of transmitter's metal house. To 
achieve this i used about 2 meters of coaxial cable RG214 between the variable 
capacitor and the antenna's feed point. After  this change i have very high SWR 
!. With 25w FWD power output, i have 1w RFL power! What do you think is the 
problem? The 2 meters RG214? I am thinking that these 2 meters of RG214 cable 
are putting paraller capacitance between the feed point and the ground system. 
How can i zero this capacitance? If i put a varable coil in paraller with the 
RG214? Or it is wrong to use RG214 between variable capacitor and antenna's 
feed point and i must use RG214 only between transmitter and variable capacitor?
thank you

UR RST IS ... ... ..9 QSB QSB - hw? BK

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