Marti frequency control module temperature

Gotta watch those Fresnel zones!
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Marti frequency control module temperature

Post by ChuckG »

Marti used these in their STL transmitters. Basically a heater module strapped to the crystal with a transistor controlling the heater current.
Unfortunately I can't get into the heater module without destroying it and these things are unobtanium from BE.

Anyone know roughly how warm/hot these should run? I have one that is operating but is far hotter than I remember them being. Not sure if there is a temp control element that has failed, or my memory has failed. :D
Chuck Gennaro
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Re: Marti frequency control module temperature

Post by kcbooboo »

A Moseley PCL6000 manual claims (in several places) their crystal ovens operate at 65C. I would think they have to run at slightly above the maximum temperature the unit is rated for, such that the crystal will always be higher than the highest ambient operating temperature expected. That manual says that's -20C to 70C, but perhaps the 65C is still high enough to get it on frequency. Perhaps the Moseley units are similar.

Bob M.
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Re: Marti frequency control module temperature



Your question and Bob's comment got me scratchin my head. Did some real quick googling and found this. It might help.

"For instance, a crystal may be specified as having a frequency tolerance of ±50 PPM @ +25°C in a frequency stability of ±50PPM over an operating temperature. This would give the crystal an overall stability and tolerance budget of ±100PPm or .01% potential frequency error".

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