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

[Magnus Danielson]

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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