[time-nuts] Hydrogen Maser KIT!

cdelect at juno.com cdelect at juno.com
Sun Sep 14 13:16:50 EDT 2014

Well, I bet that got your attention!

My Hydrogen Maser "kit" arrived recently.

It's a surplus Sigma Tau VLBA-112 with an unknown physics package problem
that has had its power supply modules, RF receiver modules, synthesizer
and cavity servo tuning modules, and a couple other "bits" removed for

Also it has been opened up to the level that the storage bulb could be
removed. (Magnetic shields, insulation, and bell jar removed)

The two main problems (so far, fingers crossed) are that the palladium
silver purifier/leak valve is missing (along with the Hydrogen supply
bottle), and that the storage bulb coating looks to be shot.

I've been tracing the power supply wiring and design, and should be able
to replace the missing stuff easily.

Minor problems are fabricating connectors for the ion pumps, replacing
one missing oven control module, and finding a Perkin Elmer pump
controller (150ma) for a reasonable price.

Once the bulb and purifier problems are cured the  major efforts will be:

-to reassemble the cavity, shields, and bell jar.
-bakeout and pumpdown the ion pumps (in isolation) 
-bakeout and pumpdown the system.
-stabilize the ovens and initiate the Hydrogen discharge.

Then if oscillation can be achieved the RF system can be built.

Replacing the Automatic cavity tuning will come last as it's not needed
for basic operation.

I plan to add a relay on the input of the EFOS2 Maser that lives here.
This will allow the EFOS RF systems to be utilized for testing before
having to build up the new receiver.

This will be a LONG term effort and I will share the progress as I go

Some info:  Copper cavity loaded with Quartz dielectric cylinder and
Quartz bulb.
                Cavity Q (loaded) 36000
                Line Q approx 1.6X10+9
                Drift < 5 parts in 10-15 per day (Auto tuner on)
                Temperature sensitivity < 1 X 10-14 per degree C
        `        Weight 525 pounds (including backup battery)
Tom has kindly posted some PIX at: http://leapsecond.com/corby/maser/

You might want to look at the old posts about homemade Hydrogen Masers
starting back in Aug 29 2010.



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