[TenTec] OMNI V Frequency Changes

[Bob McGraw - K4TAX]

Depending on if the model has the oven type crystal or the TXCO for the 
master oscillator.  If one removes power the oven cools.  When power is then 
applied the oven must come up to operating temperature.  During this time 
interval, the radio will be up to 100 Hz in error with regard to frequency. 
The later radios with the TXCO does not have this issue.   The solution for 
the oven issue is to leave DC power applied but turn the radio off.    Of 
course the oven could be defective at which point one must just rely on the 
internal radio temperature to stabilize.

Second area is the BFO crystals are not oven controlled.  If you are doing a 
lot of transmitting such as RTTY  or PSK then the heat from the PA migrates 
into the radio and will cause these crystals to move a bit.  A small fan 
mounted on the heat sink will usually eliminate this issue.

Crystals do age and thus will change frequency over time, somewhat 
accelerated by heating and cooling.  A proper alignment will usually restore 
things to normal.

73
Bob, K4TAX


----- Original Message ----- 
From: "Scott Shepard" <scottsheppard at videotron.ca>
To: <tentec at contesting.com>
Sent: Thursday, February 27, 2014 7:12 PM
Subject: [TenTec] OMNI V Frequency Changes


>I have had similar issues for a while..the v9.2 chip is brilliant and I 
>love the rig...but, if I change bands or if I leave the rig off for any 
>length of time, it will be off freq...as though the warming/cooling cycles 
>causes something to change. I have yet to go in and clean each connection 
>but it mat be needed. Also, I read something somewhere about the quality of 
>crystals used? Maybe time to have some high quality xtals cut?
>
> Scott. Va3ied
>
> Sent from my iPad
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