[time-nuts] Rubidium Oscillators and Racal 1992

[Max Skop]

Hi all,
I have replaced the lamp in an FRK with out to much trouble. When I got the 
unit it had no output so I purchased a couple of lamps on e-bay for $30 ea. 
The glue holding the lamp looked like Silastic. I cut the glue with a small 
knife and removed the lamp intact. I filled the holder with new Silastic and 
pushed  the new lamp in to the same depth. Allow to dry and a working 
oscillator.  Initial start up took about 15-20 minuets before lock came on. 
Its not hard to do and well worth the result.  Does anyoneone need a well 
used lamp slightly yellow in colour?

Regards
Max  VK3YBA


----- Original Message ----- 
From: "Ulrich Bangert" <df6jb at ulrich-bangert.de>
To: "'Discussion of precise time and frequency measurement'" 
<time-nuts at febo.com>
Sent: Wednesday, 12 March, 2008 5:20 PM
Subject: Re: [time-nuts] Rubidium Oscillators and Racal 1992


> Gentlemen,
>
> I would like to place emphasis to the fact that the so called "lamp
> voltage" is just the operating point of a regulation loop in which the
> lamp's health is ONE of the involved parameters, exactly as Antonio's
> experiments verify.
>
> Within the lamp a plasma ignition is excited by means of an external
> electromagnetic field. The field's frequency as well as the lamp's
> temperature (which is in the near of 110 ?C) are important parameters
> for the quality of the plasma ignition and for where the operation point
> of the loop is.
>
> When Antonio was "Adjusting the capacitive trimmer solid with the lamp
> assembly (and) the lamp-V ranged from 1.5 to 6.5 V" he demonstrated the
> dependance of the operation point from the exciting field's frequency.
> Not sure whether the LPRO also has, but the FRK-Ls have trimmers for the
> temperature setpoint of the lamp's temperature controller. Would he have
> changed that he would have observed a similar dependance. And when "the
> lamp-V oscillates within 10 milliVolt basicly according to ambient
> temperature" this is simply the effect of the temperature controller's
> inability to control the lamp's temperature perfectly despite of ambient
> temperature changes.
>
> So a better phrase would be that the lamps voltage is an indicator of
> the lamp's health IF and ONLY IF everything else is sane. Don't blame
> the lamp before you have checked the temperature and the exciting
> field's frequency.
>
> I am stressing this a bit because exchanging the lamp is not exactly
> easy! While it is a snap to remove the lamp toghether with the lamp
> holder (a small metallic part that makes the whole thing look like an
> ordinary bulb) the lamp itself (which is ONLY the glas compartment) is
> glued (?) to the lamp holder and in order to exchange the lamp I guess
> you will need to destroy the current one and the glue in the new one.
>
> Has anyone of you already performed that action or can give an clue
> which adhesive is suited for that purpose???
>
> Best regards
> Ulrich Bangert, DF6JB
>
>> -----Ursprungliche Nachricht-----
>> Von: time-nuts-bounces at febo.com
>> [mailto:time-nuts-bounces at febo.com] Im Auftrag von iovane at inwind.it
>> Gesendet: Dienstag, 11. Marz 2008 15:31
>> An: time-nuts
>> Betreff: Re: [time-nuts] Rubidium Oscillators and Racal 1992
>>