RF transistors have multiple emitters. If one or more (but not all) of these
emitters fail the low frequency gain will be reduced.
Dave, VE1ADH
Message: 1
Date: Fri, 25 Apr 2008 11:43:21 -0500
From: "Speer, Doug" <Doug.Speer@FairbanksMorse.com>
Subject: Re: [TenTec] Omni VI TX power low on one band
To: <tentec@contesting.com>
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<1D095086915A3E4F801FA6C08EBDD9BE015E5D8D@fme0ex02.login2.EnProIndustries.com>
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I posted a similar question a couple of weeks ago. My Omni VI Plus which I
bought from a SK estate had been in storage for many years. When I bought the
rig it seemed to work fine on 40-10m but I was getting low output ~20 watts on
160m and 80m. I sent it to Ten-Tec and they replaced the finals and drivers at
a rather healthy cost. I got the rig back just this past Monday and now all
bands seem to be working per spec. I asked Ten-Tec for a technical explanation
of how final output transistors could work fine on the upper frequency bands
but not on the lower frequency bands but never got an explanation other than
"the finals were bad".
Your problem may be similar however I would certainly run to ground your LP
filter theory before looking at final output transistors.
Doug, W9PN
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