[time-nuts] CS reservoir depletion

Bob Camp lists at rtty.us
Fri Jan 14 17:11:01 UTC 2011


The 105 oscillator is a nice OCXO. I certainly would not throw one away.
There are indeed better parts out there. It all depends on what you are
trying to do. 

The phase noise of the unit is not as good as some of the 10 MHz stuff. I
would not base a microwave synthesizer on one. It's short term stability is
a "depends on the one you have". Testing would be needed here. Aging wise it
should be pretty good. That assumes it was on power for a good part of it's
life. If it's been on the shelf for 20 years, you may need to run it for a
while ...


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of EB4APL
Sent: Friday, January 14, 2011 10:05 AM
To: time-nuts at febo.com
Subject: Re: [time-nuts] CS reservoir depletion


I can get a 00105-6013 xtal oscillator that is the type used in the 
5051A and 5065 standards.  Does it worth for a standalone frequency 
standard or the more modern compact types such the miniature units from 
the telco towers salvage coming from China are more convenient?
I realize that I need to provide both with a low noise power supply, 
specially for the frequency control voltage, but the in modern ones the 
supply issue is simpler and they give the (usually) more convenient 10 
MHz output instead of 5 MHz.  I don't know if the HP unit is usually 
quieter or more stable.
I also I know that it depends of the intended use. In this case it is 
for my home lab which includes a compact Rb and a soon to be built GPSDO.

Ignacio, EB4APL

El 14/01/2011 7:01, Tom Van Baak wrote:
>> Hi Tom been quite a while hope you are well.
>> The never run out comments, not from me. Look at the
>> previous thread I tagged onto. My humor is that most of
>> the CS tubes we get are very long in the tooth usually
>> way past whatever anyone would say they are good for.
> That is so true. It always amazes to pick up a 30 year old
> 5061A and find that it still works. Sometimes the reason is
> that it is already on its 2nd or 3rd replacement tube before
> it went to surplus. In which case you're happy for years.
> Other times it may be that the 5061A was used only very
> intermittently and the tube is the low S/N original.
> A real gem would be one that was kept in cs-off mode except
> for a few hours once a month to keep the OCXO within some
> loose cal lab spec. Even after decades it would be as good
> as new.
> For many frequency applications there is no reason to run
> in full cs-locked mode. This is also true if you need good
> short-term stability. The free-running OCXO in most Cs (and
> GPSDO for that matter) are more stable short-term when the
> loop is open.
> /tvb

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