Crystal oven for a SSB rig

[Zman]

Whats an easy way to make a crystal oven to keep a drifty SSB rig on freq?

 

[Mudfoot]

http://www.worldwidedx.com/showthread.php?p=289161

Might help, might not.

 

[Zman]

Very cool but mousers website is designed for techs and engineers and not user friendly for CB goofballs like me!

 

[Mudfoot]

Needle Bender said he bought a box full. Maybe he can help you with your quest.

 

[Captain Kilowatt]

We used to wire up a small resistor and affix it to the crystal then encase it all in a small block of styrofoam. Yoi only needed a remarkedly small amount of heat as the styrofoam kept it in.

 

[Robb]

Might also want to add an adjustable compression cap to the reference oscillator crystal circuit - so that it can be set at the correct freq when warmed up. But the overall stability results are still going to depend on the model of the radio used. Some radios have other issues with freq stability that are not going to be cured with stabilizing just the reference oscillator crystal temperature (e.g. 3600 series chassis radios). . .

Just sayin . . .

 

[bob85]

these work well as a poor mans oven, Kuhne electronic*|*QH 40 A
but heating the crystals won't fix a drifty cb that has unstable oscillators by design,

the temperature coefficients of the oscillator components need to be better balanced so that the positive temperature coefficient components cancel the negative coefficient components to minimise thermal drift.

 

[Captain Kilowatt]

BTW a lot of the time the drifting is not due to the crystal but rather poor quality trimmer capacitors. true crystal ovens usually heat the entire oscillator including the crystal, trimmers, and transistors keeping everything stable.

 

[Robb]

BTW a lot of the time the drifting is not due to the crystal but rather poor quality trimmer capacitors. true crystal ovens usually heat the entire oscillator including the crystal, trimmers, and transistors keeping everything stable.

Yep.
But in some CB's (aka the popular 3600 series chassis), the loop oscillator tuning cans are the culprit. Hit em with a shot of 'air from a can' and watch the freq go wild all over the place. Been there; done that. There has been many who have tried to make this situation right - to no avail. Some tried using different ferrite cores (changing the permeability) in the cans to see if it would help - but that was a 'no-go'. Those coils have just too much change due to their given value. Extremely fussy to adjust as well . . .

 

[Zman]

I used a small bulb.. Tamed it right down..

 

[Mudfoot]

Pic?