RE: Need help-SWR increases with power...

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From: Kevin Muenzler, WB5RUE (wb5rue@arrl.net)
Date: Wed Dec 27 2000 - 16:24:40 CST


You probably have something close to the antenna, including the ground, that
is becoming significant with the increased power. I have the same situation
with a 2-meter J-pole. At 10 watts I get about 1.2:1. If I increase to 300
watts the television antenna 20 feet away causes the SWR to increase to 2:1.
How do I know it's the TV antenna? If I take the antenna down the SWR goes
down to 1.2:1 at 300 watts.

You might also have an insulator (or coax) that is breaking down with the
higher voltage. Check your connectors as well. You might have a bad joint
that doesn't show up until you increase the current through it.

Hope this helps.

Kevin, WB5RUE
I am Voltohm of Borg! Resistance is E/I, power is EI, you will be
attenuated!

> -----Original Message-----
> From: owner-qrp-l@Lehigh.EDU
> [mailto:owner-qrp-l@Lehigh.EDU]On Behalf Of
> Steve Hanson
> Sent: Wednesday, December 27, 2000 3:56 PM
> To: Low Power Amateur Radio Discussion
> Subject: Need help-SWR increases with power...
>
>
>
>
> Why does my SWR reading increase when I increase power? For
> example, on 40M
> at 4 watts into my untuned 130' dipole, SWR reading, both on my TT 580
> Delta, and on outboard Kenwood meter is abt 1.2, BUT, if I
> increase power
> to, say 80 watts, My SWR will go up to about 2.5+. I can
> tune the ant. to
> bring it back down, but why does it go up with power? Will I
> blow my finals
> if I continue to run at 4 watts to untuned ant with both
> meters reading 1.2?
>
> Many thanks,
>
> Steve in Maine KE1LG
>
>
>


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