[time-nuts] Re: What to expect from rubidium lock behavior?

[paul swed]

Wilco
Great to hear from you. Here is my 10 cents. Most of the things we happen
to find are generally of the telco grade. The FRS as an example is a nicely
built unit that used to be had for as little as $25. I picked a few up.
Well maybe 8. These had all been in service (approx 1994) and so after a
while they tended to suffer the plating out of the RB on the lamp. Ending
the useful life. Thanks to time-nuts its been shown you can melt the RB off
the lamp and you are back in business. For me at least another 5 years. The
better units most likely have better reserve in the lamp. Maybe easier to
repair and be stabilized perhaps a bit better.
I would trust Bob's thoughts, thats why mine is worth 10 cents.
Regards
Paul
WB8TSL

On Sat, Dec 11, 2021 at 1:37 PM Wilko Bulte <wkb at xs4all.nl> wrote:

> hi Paul, Bob,
>
> Is there a significant difference between these telco-surplus Rb and the
> more 'fancy' ones in this regard?
>
> I happen to own an Efratom MRK-HLN, which, I presume, is also more geared
> towards "always on". So, I wonder would the MRK be better or worse compared
> to a telco-surplus unit? Arguably a telco-surplus unit is also of the
> always-on variety or?
>
> best,
> Wilko
> (newbie trying to get a feel for this)
>
> > On 11 Dec 2021, at 16:27, paul swed <paulswedb at gmail.com> wrote:
> >
> > Totally agree with Bob. Same experience.
> >
> >
> >> On Sat, Dec 11, 2021 at 8:12 AM Bob kb8tq <kb8tq at n1k.org> wrote:
> >>
> >> Hi
> >>
> >> Yes, that’s pretty normal operation for any of the telecom Rb’s. They
> >> also typically drift about 1x10^-9 over the first day of operation. It’s
> >> best to leave them running all the time. Second best is to turn them
> >> on a couple days before you need to use them.
> >>
> >> Bob
> >>
> >>>> On Dec 11, 2021, at 2:23 AM, Erik Kaashoek <erik at kaashoek.com> wrote:
> >>>
> >>> My rubidium frequency standard (Accubeat AR60A) finally got its nice
> box
> >> with good cooling and some LED's showing the status.
> >>> While watching the unlock LED I noticed the AR60 say's it is locked,
> >> about 4 or 5 minutes after cold start, when the frequency error jumps
> below
> >> about 1e-8
> >>> It takes 2 or 3 more minutes of slow drift to become stable within
> >> 1e-10. Is this to be expected?
> >>> With this locking speed it is tempting to switch off the AR60A unless
> >> needed for some measurement. Would daily switching on/off have any
> impact
> >> on lifetime?
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