[time-nuts] Rubidium Oscillators and Racal 1992

[Ulrich Bangert]

Max,

most interesting comment!

So far you are the first person from which I hear that he has exchanged
the lamp. If I am wrong concerning the difficulties of lamp exchange:
Even better so!

I just checked the Dow Corning web pages to find 373 different products
that have "Silastic" in their name. Which of them did you use? 

73s de Ulrich, DF6JB

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Max Skop
> Gesendet: Mittwoch, 12. Marz 2008 10:42
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] Rubidium Oscillators and Racal 1992
> 
> 
> 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
> >>
> 
> 
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