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Re: Topband: alternative to vacuum variables

To: <richard@karlquist.com>, "'Pete Smith N4ZR'" <n4zr@contesting.com>
Subject: Re: Topband: alternative to vacuum variables
From: "N4IS" <n4is@comcast.net>
Date: Fri, 25 Jan 2013 04:14:01 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Pete Smith N4ZR wrote:
> One of the reasons I have mot gone to high power on 160 is the cost of 
> capacitors for my omega match - at least $300.  Anyone know of any 
> workable alternative?  I remember someone writing about using 
> coiled-up RG-8, RG-213 or maybe Teflon coax.  Where can I find more
information?

Yes, there is a great solution, I'm using it for almost 10 years. The issue
with capacitors in 160m is the dielectric an most capacitors get hot and
change the capacitance. I used 19 x 62 pFNPO 3KV capacitor  to get 1200pF.
Never had a failure. Just keep them apart , don't let two capacitor  touch
each other.  Just put them in parallel. You can us a receiver variable
capacitor to find the valor necessary to tune the antenna, then measure it
and replace with X 62pF in parallel. I used PTFE  tape for pipes tread to
protect the packet from the weather. 

Capacitor, ceramic. 62pF 3,000V. CERA-MITE 564CC0GAA302EL620J  

You can find it in several stores, here the price is U$ 1 each

http://www.electronicsurplus.com/Item/15444/CERA-MITE%20-%20Capacitor_%20cer
amic_%2062pF%203_000V_%20-%20564CC0GAA302EL620J/


Regards

Jose Carlos

N4IS



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