[time-nuts] Efratom LPRO Rubidium

Ulrich Bangert df6jb at ulrich-bangert.de
Mon Jul 7 07:41:41 EDT 2008


Hal,

> My LPRO is 4 or 5 milli Hz high.  I can't see any changes 
> with temperature and my setup swings through 15 F p-p 
> during most days.

The TC of a LPRO is in the order of -7E-13 / Deg C or even less. That is
why you see no changes: They are there but a bit beyond most measurement
capabilities. 

Best regards
Ulrich


> -----Ursprüngliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Hal Murray
> Gesendet: Montag, 7. Juli 2008 10:23
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] Efratom LPRO Rubidium
> 
> 
> 
> > The unit powers up about +200 Hz  above 10 MHz (mine is 
> modified to no 
> > longer put out 15 MHz). After 30 minutes it has dropped 
> slowly to +150 
> > Hz. It briefly shows an online indication then. But a few minutes 
> > later that goes off and the fault light comes on. The 
> frequency drops 
> > as low as +129 Hz as things continue to heat up. A couple of days 
> > later its still in the +129 ~+149 Hz range. I can heat and 
> cool it and 
> > move the frequency ( +157 Hz at 90°F inside the Lucent box, 
> +129Hz at 
> > 110°F), so the loop definitely isn't in control.
> 
> My LPRO is 4 or 5 milli Hz high.  I can't see any changes 
> with temperature 
> and my setup swings through 15 F p-p during most days.
> 
> That's with the electrical tuning open and no adjustments to 
> the mechanical 
> tuning.
> 
> 
> I couldn't find any specs for the mechanical or electrical 
> tuning range in 
> the data sheet.  Has anybody measured it?
> 
> 
> 
> 
> 
> -- 
> These are my opinions, not necessarily my employer's.  I hate spam.
> 
> 
> 
> 
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