On 8/28/2010 6:16 PM, Neil & Heather wrote:
> I saw some traffic on the relector this Month
> on the SWR curve on the C19XR, specificlly 15m,
> and trying to get a good match,and thought I would just share some of my
> notes with the group.
> I have been having an intermittent short when rotating my Force 12, and
> presumed it to be a bad section of coax or a bum connector.
> Well, yesterday and today I was able to get up the tower and investigate.
> What I found was the connector on the stock supplied coax balun ,(Cal-Av
> Labs EB-1)had pulled out,and the "ground" side of the balun was
> open...therefore rendering the balun junk.
> (with no easy way to fix!)
> So, I wound a coax air choke, 6 turns RG213, 5" in diamater, just so I
> could get on the air until I was able to order a new ferrite balun.
Read Jim Brown's RFI tutorial and specifically the section on current
baluns. Then get some cores and make a "good" current balun. I replaced
the original balun "stick" with 5 turns of Davis BuryFlex(TM) on 5 2.4"
> Let me back up here just a bit , and say the main reason for this post,
> is that I was never able to get a better than 1:9:1 SWR on 15m. no
> matter how much I played with the "feed" wires
> between the 10m and 20m drivers,and the best 20m match I had was 1:4:1,
> that was until I put the coax choke up...now, my SWR is down to 1:4:1
> across the whole 15m band.It is also a perfect 1:0:1 0n 20m
> from 14.170 to 14.250, best match ever.
> Now I can't say why the coax choke is giving me a better match..and
> still think the EB-1 is a good balun, and will still get a
> replacement...but, its hard to argue with the
> swr #'s on the analyzer.It might be a while before I change that balun!!
> Just thought I would share this with other C19XR ownwers..
> 73 es de AE1P,
> Neil G
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