[time-nuts] OT Gel Cell question
Brooke Clarke
brooke at pacific.net
Mon Jul 28 16:56:32 UTC 2014
Hi:
Using lead acid batteries and a precision frequency standard is not a good thing if they are too close together.
A number of decades ago (before the Time Nuts or the internet) I was able to purchase a rack mount Gibbs 5 MHz double
oven frequency standard that used a very nice Bliley glass tube crystal because it was not as precise as is was supposed
to be. It used GelCell backup batteries that were physically in the same rack chassis as the oven. The fumes from the
batteries when charging etched some traces off the PCB inside the oven defeating the temperature control but leaving the
oscillator. It took a long time to reverse engineer and repair it. I've added a photo of the cord wood construction of
the cylindrical oscillator. The core of the cylinder holds the glass bottle crystal and the glass piston coarse tuning
capacitor, surrounded by the first heater, circuitry for the oscillator and dual temperature control circuits on ring
shaped boards. These fit inside a cylindrical cavity which is the outer oven. I've added a photo of the inner assembly
at:
http://prc68.com/I/office_equip.html
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
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