[TenTec] Omni VI frequency jumping/drifting

[k4mt1950 at charter.net]

It does it on all bands and you will never notice it in normal
operation. If I tune in carrier on WWV and watch it in fldigi I can
see the freq vary a bit back and forth and the WWV carrier looks like
I sine wave as it cycles back and forth. 
I have spent hours with freeze spray etc and can not isolate any one
part. You can also see if if you monitor PLL control voltage as it
will swing up and down slightly after radio gets hot.
I know 100 guys will tell me there radio never does this as t cant be
possible but I have had several guys run controlled tests and they see
the same on their units.
Again normal operation it wont show up but on FT8 I noticed I was not
decoding all of the signals and could see a tilt on the FT8 signals.
Not much variation but enough for FT8 to not decode.
Dont run FT8 and it will never be seen as freq cycling is very small
Gary K4MT

	-----------------------------------------From: "Ken Brown" 
To: "Discussion of Ten-Tec Equipment"
Cc: 
Sent: Thursday June 28 2018 8:11:26AM
Subject: Re: [TenTec] Omni VI frequency jumping/drifting

 If you have a stable general coverage receiver you can listen to each
of
 the oscillators to see which one is drifting. May have to experiment
with
 methods of getting a sample of each oscillator to the receiver.

 On Wed, Jun 27, 2018, 19:06 Bob McGraw K4TAX  wrote:

 > I start with my original suggestion for old radios such as this.
"Clean
 > connectors". All of them. One at a time, unplug the connector,
using a
 > Q-Tip with contact cleaner applied, scrub the male pins. Then push
the
 > connector on and off a couple of times to wipe the female contacts.
 >
 > Drifting.....is the master oscillator drifting? Could be the oven
 > cycling excessively. Or could be a BFO crystal, although that would
 > likely affect all bands. However, they are in the rear near the PA
and
 > the heat migrates noticeably into that area. They are really not
 > temperature compensated.
 >
 > Yes, you can tweak the coils on the band oscillator board to get
them on
 > frequency but usually something else is causing drift. Bad BFO cap
has
 > been known to do this.
 >
 > Check the BFO alignments per the manual, and in the order defined
for
 > all modes using a frequency counter.
 >
 > 73
 > Bob, K4TAX
 >
 >
 >
 >
 > On 6/27/2018 8:38 PM, Stan Gammons wrote:
 > > Hi Everyone,
 > >
 > > My Omni VI has decided to throw a few more fits. First the
frequency
 > > jumped on 30 meters, but FT8 signals still decode fine. So I let
it go
 > > and didn't mess with it. Lately 40 meters has started throwing
fits
 > > and it's much worse than 30 meters. Looking at the FT8 waterfall,
at
 > > times it will drift during the 15 seconds and it's bad enough the
FT8
 > > signal won't decode. I sent another email to the list with the
 > > waterfall pic attached, but the message was too large and got
 > > rejected. I tried tweaking the coils on the crystal oscillator
 > > board. It might have helped 30 meters a little. Doesn't seem to
have
 > > done much/anything for 40 meters though. Crystals gone bad maybe?
If
 > > so, anyone know a source now that ICM is no more?
 > >
 > >
 > > 73
 > >
 > > Stan
 > > KM4HQE
 > >
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