Towertalk
[Top] [All Lists]

[TowerTalk] SWR shifts with power

To: aa4lr@arrl.net
Subject: [TowerTalk] SWR shifts with power
From: "Howard Klein" <howk2@hotmail.com>
Reply-to: rf@xemaps.com
Date: Tue, 24 Jan 2006 21:05:05 +0000
List-post: <mailto:towertalk@contesting.com>
Bill,
I had a similar problem with the same symptoms. In my case it seems my shunt 
wire, actually 3/8" cu tubing, got blown close enough to the tower for it to 
arc with high power. Hope your solution is that simple.
Howard..K2HK



I'm having trouble with my shunt-fed 15m tower. I have an L matching
network that is switched between 80 and 160m. A relay selects
different taps on the inductor, and also adds capacitance for 160m.

If I use an MFJ 259 antenna analyzer, I can get a nice match on
either band. And if I transmit with a few watts, I have no problem.
Even the 20 watts that the KAT100 uses isn't a problem.

However, if I transmit about 70 watts or more, the SWR suddenly
shifts to 3:1 or worse. It changes with each transmission.

I thought the caps might be arcing, so I replaced one of them with a
wide-spaced variable, same problem.

Any suggestions?


_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk


_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>
  • [TowerTalk] SWR shifts with power, Howard Klein <=