[amsat-bb] Re: Possible SWR problems with 70cm antenna

Greg D. ko6th_greg at hotmail.com
Wed Jun 4 23:34:40 PDT 2008

> From: rogerkola at aol.com
> To: amsat-bb at amsat.org
> Date: Wed, 4 Jun 2008 08:01:27 -0400
> Subject: [amsat-bb] Re: Possible SWR problems with 70cm antenna
> "... The way
>>> the power out meter on my radio acts, it leads me to believe I may
>>> have an SWR issue. Unfortunately I don't own or have access to an
>>> SWR meter or anylyzer capable of working at 70Cm..."
> You don't mention what rig you have but many of the modern transceivers have
> High SWR protection circuits and will cut back on the power as evidenced by
> the meter already in the rig in the presence of return power.

Actually, I've seen the reverse - the meter on my Yaesu 767GX seems to read higher when the match is going bad.  Seems like it's reading both the forward and reverse power and adding them together.  So, you get a higher number when in fact the transmitter is putting out less.  Counting some of the the watts twice.

But, back to the original problem, you might consider making something simple as a 1/4 wave ground plane antenna, or using the rubber duckie from your HT, and putting it in place of the suspect one.  Think of it as a slightly radiating dummy load, which it is.  Just watch the power rating if you use your HT antenna.

Greg  KO6TH

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