[time-nuts] Source of Rubidium Lamp for Efratom FRK

Bob Camp kb8tq at n1k.org
Wed Jul 29 17:34:05 EDT 2015

> On Jul 29, 2015, at 11:23 AM, Mike Niven <mfniven at ymail.com> wrote:
> Thanks for the comment Bob.  Tracing Efratom through the ages, I see they are now Microsemi.  I wonder whether they will still have a lamp for such a geriatric Rb source and at what price - probably more than the cost of the complete Racal 9475?  I will follow it up anyway as I hardly ever see working or scrap FRKs for sale in the UK.


I believe that the last lamps I bought were when the devices were still in their catalog (no web sites back then). Price was in the $300 to $600 range for a bulb. I simply do not remember the exact price from 20+ years ago.


> --------------------------------------------
>> On Tue, 28/7/15, Bob Camp wrote:
>> Hi
>> The Efratom bulbs have a “magic mix” of gas in them. The only place I have ever 
>> bought them is direct from Efratom. They were fairly expensive back in the early 90’s …
>> Bob
>>> On Jul 28, 2015, at 9:56 AM, Mike Niven <mfniven at ymail.com> wrote:
>>> Would anyone know of a source of the Rubidium bulb fitted in the Efratom FRK (and probably other FRx) standards?  I have repaired and refurbished my Racal 9475, which is fitted with the older style FRK (not -H or -L) module.  It is working properly at present but the lamp voltage is down to 5.5V, which is below the stated minimum of 6V.  I have tried rejuvenating the bulb using a hot air gun, as described by Corby, but this has had no obvious impact.  Hence, I have little feel for how much life the existing lamp has left and a spare would be good for my peace of mind.
>>> Many thanks.
>>> Mike
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