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[TenTec] Omni V & Autek WM-1 observation

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Subject: [TenTec] Omni V & Autek WM-1 observation
From: badger@vbe.com (Michael Melland)
Date: Mon, 28 Dec 1998 19:44:06 -0600
Here's an interesting observation I made today.  I was near 21.030 today
and decided to send a cq.  This was probably my first time on this freq
with my Omni V.  As I was sending I noticed that my new Autek WM-1 meter
was indicating I was only putting out about 70 watts.  I checked both
peak and average and the meter read 70 watts in both positions.  Next I
went up band to about 21.320 and the WM-1 then read it's normal 100
watts.  To check the rig I hooked my Bird meter (recently certified) up
to the rig and into my dummy load and went back to 21.030.... sure
enough..... 100 watts. Then I hooked up the Bird to the antenna....100
watts out.  Next I hooked up the WM-1 direct to the dummy load......
yep....100 watts.  Hooked up the antenna again to WM-1 and back to
indicated 70 watts???? I then hooked the Bird to the antenna in line
with the WM-1 to compare readings and now they both read 100 watts
but.....get this... if I take the Bird out of the line and hook the
antenna back up direct to the WM-1 it's back to 70 watts !!  Thought it
was RF but touching/grounding the WM-1 remote line section or meter has
no effect on the reading nor does running the meter off battery power
instead of the wall wart power supply it has.  

Any suggestions as to what's going on here ?  Autek told me that it's
not RF in the meter and that it's because the Omni is shutting down
output due to either high SWR or reactance, in other words the meter is
correct and the rig is shutting down power..... but then why does it
read ok by the Bird ? And why is the current not maxing out to the rig
from the power supply ?  And, my antenna analyzer and the Bird nomagraph
of reflected vs forward power both show a SWR abt 2:1 on the line.  Odd
that it's only affecting 15 meters..... all the other bands have
tolerable readings....... I STILL suspect RF.  Oh yeah..... the ground
is from a 3' buss behind my desk connected to a 2" copper flashing
through the wall (abt 1.5' in the shack) to a ground rod outside.

Michael Melland, Researcher/Lecturer
Carroll College Institute for Civil War Studies
Waukesha, Wisconsin

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