[time-nuts] Re: Frequency Standard - Where Can I Get One.

[Bill Notfaded]

There's no substitute for a few good rubidiums.  OCXO and Rb are
different.  It's really hard to beat a really good GNSS diciplined Rb!
Extremely good holdover.  We're timenuts after all right?  Where's the fun
if you don't try them all?  There isn't any silver bullet or perfect
solution but I've found with some good measurement and comparisons you too
can be in the search of better and better stability.  Half the fun is
finding a better OCXO or finding a really stable Rb.  Testing them all
against each other is part of the journey.  Letting timelab run all night
every night.  Flipping back and forth between graphs.  For me it's a hobby
but I've gotten many many hours of great happiness from it.  The first time
I got into 10 ^ -13 how can you explain what that's like?  The huge digits
on an SR620 you can read from across the room.  I guess it's different for
each of us but it's something we all share.

Bill

On Sun, Nov 21, 2021, 1:58 PM Magnus Danielson via time-nuts <
time-nuts at lists.febo.com> wrote:

> Hi,
>
> So, on that note. I am surprised that I have not seen popular telecom
> rubidiums being reverse-engineered. For instance, the LPRO-101 should
> have been reverse-engineered a long time. Some of the circuitry is known
> from patents, but those do not build up a complete schematic. I've
> considered to do the job, but apparently I have not been able to sit
> down and do that particular job either.
>
> I think the LRPO-101 should not be too much of a challenge. Beyond the
> schematic some documentation of the other functions, hints and tips,
> etc. that is related should be written up so one approach something
> similar to a service manual.
>
> With enough people contributing, I think it should not be too hard to
> collect things. We should be able to provide useful hints and tricks,
> such as suitable replacement components etc.
>
> Cheers,
> Magnus
>
> Den 2021-11-21 kl. 19:45, skrev Bob kb8tq:
> > Hi
> >
> > Well, if I could keep a 5065 running without repairs for more than a
> couple years
> > I might be more willing to agree with you. What makes the 5065 different
> is that you
> > have schematics and can do repairs. When the telecom gizmos die, there’s
> not much
> > to fall back on. They were designed to run a finite amount of time and
> then go to the
> > scrap heap.
> >
> > Bob
> >
> >> On Nov 21, 2021, at 12:03 PM, Skip Withrow <skip.withrow at gmail.com>
> wrote:
> >>
> >> Hello Time-Nuts,
> >>
> >> No offense Bob, but I would like to take issue with your statement 'Rb
> >> standards have a finite life'.
> >>
> >> There are time-nuts on this list of every skill and knowledge level
> >> and I would like to keep the information as correct as possible.  My
> >> feeling is this is not a true statement.
> >>
> >> There is nothing inherent in the design of a rubidium frequency
> >> standard that limits its life (unlike cesium).  However, there are
> >> manufacturing choices that can possibly limit time before failure.
> >>
> >> First example, of course, is the HP 5065.  There are many of us that
> >> have units that have been running continuously for close to 50 years.
> >> HP made choices in their bulb design that ensures that it runs for a
> >> very long time.
> >>
> >> An opposite example would be the Tracor rubidiums.  The lamps in these
> >> units were either horribly underfilled, or the glass was very reactive
> >> with Rb and almost all suffered from rather early lamp failures.
> >>
> >> Then, there is the huge mass of telecom rubidiums.  As you stated,
> >> keeping the base plate at a reasonable temperature goes a LONG way to
> >> extended life.  Excessive temperature obviously leads to higher
> >> component (and sometimes lamp) failure.
> >>
> >> There are also units that just did not have enough design margin in
> >> certain areas.  The SRS PRS-10 is one of these where I have seen
> >> things go up in smoke in the lamp area.  BTW, the HP 5065 can have
> >> some issues in this area as well.
> >>
> >> I'm obviously a big fan of rubidium frequency standards.  My advice to
> >> newer time-nuts is that you can't go wrong owning one (better long
> >> term stability than OCXO, lots less cost and longer life than cesium).
> >>
> >> I'll get off the soap box now.  Thanks for the bandwidth.
> >>
> >> Skip Withrow
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