Not to mention, if the reading at first is with the SWR off and the radio's 
cutting back, you hit the tuner and get the radio up to the 100 watt out put 
again because it's seeing a load it likes, that can vary the readings a 
little too.
----- Original Message ----- 
From: "Butch Bussen" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, November 15, 2006 6:07 AM
Subject: Re: TW1 Inconsistancy


> Actually, the internal tuner can effect the readeings.  If you want an
> accurate reading, be sure the tuner is off.  The tuner makes the radio see
> 50 ohms, but the impedence of the line and load on the output, the
> antenna, and the load back toward the radio, the tuner, can be far from 50
> ohms.  The meter is designed to run in a 50 ohm circuit, which it isn't
> any more.  I fought this battle a while back trying to tune up a six meter
> antenna on the 2000, and got all kinds of strange readings until I
> remembered to turn off the tuner.  The tuner does effect things, because
> it can present a high impedence to the meter on that end.  Also, you'll
> find that sometimes just changing the length of the cable between the rig
> and the meter can change readings.  I had a regincy 2 meter rig once and I
> was just a beginner in all this stuff.  I had run another radio on my 2
> meter beam and knew the beam was working great.  The regincy worked great
> on my mobile, but when I hooked it up to the beam, no output.  As they
> came from regincy, they were very sensative to a "high s w r", and would
> shut down.  I thought o.k., I'll check the swr.  Put the meter in the
> line, and radio worked fine.  Took the meter out, and no output.  I
> finally found that by either adding 6 inches or cutting six inches off of
> the line made the thing work.  It was dependant on exactly where in this
> run of 70 feet of coax the radio was.
> This is why if you are checking the s w r on a 72 ohm line, you have to
> change some resisters in the meter so it matches the line.
> 73s
> Butch Bussen
> wa0vjr
>