Peter: my Omni VI rev 3 had the old logic board and it did require
powerapplied 24/7 to maintain stability. The Omni VI+ did not require power
allthe time because of the TCXO on the later logic board. There is a write
upon the TneTec wiki page.
If you could find a TCXO now, it would be a good upgrade but doubt thatTenTec
still has them available. I have heard that all kinds of parts went tothe
landfill before the new owner arrived. Might try to find a logic boardfrom a
parted out 564 for your radio.
I still have my 564 and it will be on the desk until it (or I ) become a SK. HI
73 Clayton N4EV
From: Peter Klein <pklein@threshinc.com>
To: tentec@contesting.com
Sent: Monday, July 4, 2016 8:14 PM
Subject: [TenTec] Omni VI instability, TCXO worth it?
I queried service@tentec.com by email about the following issue last
Tuesday. I have heard nothing so far, so I thought I'd get some advice here.
Background: I live in the Seattle area. I have modest wire and vertical
antennas. I'm not a contester or hard-core competitive DXer. I do try to
work DX when I can, and I might jump into a contest to snag a new
country. But mostly I do HF digital (PSK, Olivia, MFSK), casual CW, or
occasionally SSB.
I've owned my Omni VI for 20 years. It has the Option 1 DSP upgrade.
Over the years, the radio has several times developed a frequency
instability issue. Over a time ranging between less than a second to a
few seconds, the transceiver moves a few 10s of Hz off frequency, then
"snaps" back. It's mostly done this on 30m, occasionally on 20m, and now
on 40m. Lately, it happens on 40m, with a short "period," so if I am
listening to a good, pure CW signal, it sounds like it has old-fashioned
"chirp."
The frequency shift occurs on both transmit and receive. When it
happens, if I switch to another band, it does not happen there. It is
intermittent. Sometimes it appears random, and sometimes appears
temperature-related (for example after transmitting for a while, or if
the radio has been just turned on in the last half-hour or so).
When it first happened (1997), Ten Tec Service advised me to tweak the
trimmer coil to the 30m mixer crystal 1/8 to 1/4 turn in either
direction until the "drift and snap" stopped, and just live with the
slight display error. I did, and later did the same thing to the 40m
coil when that band acted up. It worked in both cases.
When it started to do the frequency dance on 20m, I sent back to the
factory for a tune-up. This was in October 2013. Now, it's doing it
again on 40m.
I spoke to TenTec's service manager a few months ago. He said that the
problem might be solved by installing a temperature compensated crystal
oscillator (the TCXO was never suggested before). He said that I could
install this myself if I could solder a couple of wires. He quoted me a
price of $200 to send me the necessary circuit board and instructions.
He said it was up to me whether I wanted to spend $200 on "an older
radio." He was also dead-set against my tweaking the trimmer coils to
the individual band crystals.
I decided to wait and see if leaving the power supply on 24/7 would
solve the issue. Nope. And while I was waiting, Ten-Tec was sold and has
new service policies.
I would like to install the TCXO, *IF* it is very likely that it will
solve the problem, and I can get at least another couple of years of
good service out of the radio. On the other hand, the radio is 20 years
old. So if it's just as likely that I will continue to have the problem,
then maybe the TCXO isn't worth it, and I should think about a new radio.
So, what would you do if you were me?
Thanks and 73,
--Peter, KD7MW
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