Subject: [IGSMAIL-365] Concerning cheap Rubidium Standards
From: T. Clark
Date: 4 NOV 1993 09:58:50

IGS Electronic Mail        4-NOV-1993 09:58:50       Message Number 365
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From: T. Clark
Subj: Concerning cheap Rubidium Standards
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At the IGS Operations Meeting last week, I mentioned that I knew of a
source of low-cost Rubidium standards. Here is the information I have:

The contact person is a surplus dealer in Pennsylvania:

        Wade Lehman
        Lehman Scientific
        Route #1, Box 580
        Wrightsville, PA 17368
        Voice & FAX: (717)252-4211
        Voice only:  (717)244-7540

He has on hand about 25 new Ball/Efratom M-100 standards (Efratom part number
70502-1) with 10 MHz output. Apparently these units are military surplus, but
they are supposed to be unused. I have two on order but I have not seen them
yet. 

Wade Lehman's price is $800 (US) each, (and he says he will take VISA card 
for payment). He states that this price includes the Efratom manual, all 
connectors and all test reports.

Here are some of the characteristics of the M-100 standard taken from the 
Ball/Efratom data sheets:

 Output = 10 MHz, 0.5v RMS into 50 ohms, from SMA connector.
 Frequency trim range: > 3e-9
 Setability and resetability: 1e-11
 Long-term Stability: < 6e-11 first month, < 3.6e-10 1st year, < 2e-10 2nd year
 Short-term stability: Alan variance < 3e-11 for  1 sec < t < 100 sec
 DC power: +22 to 32 VDC, 18w maximum when hot, 2.2 amps during oven warm-up
 Size (inches): 4.81 high x 3.90 wide x 3.94 deep (requires heat sink)
 Weight: Approx. 9 kg

Hope this information is of use. I make no guarantees about these units as
I am simply providing information and have no connection with Mr. Lehman's
private business (i.e.   >>>> ALL CAVEAT EMPTOR! WARNINGS APPLY <<<< ).

[ NOTE: A TurboRogue requires a 5 MHz reference and these units have a 10 MHz 
  output. I would suggest that if you implement a divide-by-two circuit, you 
  should use an ECL (like Motorola 10K-series) flip-flop. We have found that 
  the 10K series chips have very good stability and phase noise. ]

Regards, Tom Clark