It depends a bit on what you mean by "cold start". If you do as the manual
suggests and leave the power supply on, the oven stays on and the frequency
should be pretty stable. If you also turn off the power supply, it takes
quite a while for the master oscillator to get stable. Also the trimmer gets
flaky when it get older and does funny things as it warms up. There is an
easy (but almost $100) fix to this.
I replaced the aging OCXO in my VI/3 with a new TCXO and it became much
more stable. It was also very much easier to get it calibrated; the
trimmer on the old OCXO was very touchy. The TT instructions are OK but
have you leaving the power connected to the old oven even though it is no
longer used. I'd suggest also disconnecting that since it just sucks up
power and generates heat.
The TCXO is a big improvement.
73
Steve WA2SOC
--- w5ot@aol.com wrote:
> My Omni VI, opt.3 has an apparent frquency instability which occurs during
> the ten minute period between 5 and 15 minutes after cold start.? Voice and
> CW signals "warble" on both transmit and receive.? Sounds a bit like FMing.
>
> Any suggestions?
>
> tnx es 73 de John, K5SEE
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