More information on the low power condition discussed below:
I suspect the inaccurate SWR reading on the internal meter is causing
the drive to be reduced to the driver/finals. The drive reduction
feedback loop is a protective circuit to keep from damaging the finals
when improper loads are encountered. I'll bet the inaccurate SWR
readings (3.:1 into a dummy load) are caused by one or both defective
Schottky diodes in the SWR directional coupler circuit. Does this sound
reasonable? Has anyone seen this before? Other things to check?
Dennis, K7FL
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-------- Original Message --------
Subject: OMNI VI - Low Power output
Date: Sat, 09 Jan 2010 11:20:10 -0800
From: Dennis Ashworth <dennis@ashworth.org>
Reply-To: dennis@ashworth.org
To: TenTec@contesting.com
The power output of my OMNI has dropped to around 30 watts, as measured
on the OMNI front panel and an external power meter. The collector
current (as displayed to front panel meter) is about 15 A. SWR
indication on the front panel is incorrect, indicating 3:1 into a dummy
load -(1:1 indicated on the external power meter).
Any ideas?
Tnx
Dennis, K7FL
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