[time-nuts] HP 100D FS [WAS: HP 105D FS]

[Bob kb8tq]

Hi

The “heated crystal” approach was pretty common up until the 1970’s. Both GR 
and HP moved over to "electronics in the oven” at about the same time(early 60’s) for rack mount
standards.  There are a few tube based OCXO’s with heated electronics. Some of them 
date to the 1960’s others appear to date earlier than that.  The 5 MHz 3rd overtone 
crystal dates to the early 1950’s and it certainly was used in standard applications 
in that era. 

Bob


> On Apr 9, 2017, at 7:20 PM, Jeremy Nichols <jn6wfo at gmail.com> wrote:
> 
> Up through and including the 101A, only the crystal was ovenized; the
> oscillator itself was not temperature controlled other than via the
> environment in which it lived. Given that the 100 series was mostly vacuum
> tubes, that is understandable. I was a little surprised to discover that
> the solid-state 101A had only the crystal in its oven and, in fact, its
> specs are no better than the vacuum-tube 100E. Later models moved more and
> more stuff into the oven and the specs got better.
> 
> Jeremy
> 
> 
> On Sun, Apr 9, 2017 at 1:02 PM Charles Steinmetz <csteinmetz at yandex.com>
> wrote:
> 
>> Perry wrote:
>> 
>>> The HP oscillator is a 100D Low Frequency Standard..
>>> Sorry for the brain fart.
>> 
>> For a bit more information on the 100D (and 100C), see the October, 1949
>> Hewlett Packard Journal:
>> 
>> <http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1949-10.pdf>
>> 
>> Note the accuracy and stability specs:
>> 
>> ACCURACY:  Average stability is within approximately two parts per
>> million per week.
>> 
>> STABILITY:  Within one part per million over short time intervals, such
>> as required to make a measurement.
>> 
>> The price in 1949 was $600 f.o.b. Palo Alto.
>> 
>> Best regards,
>> 
>> Charles
>> 
>> 
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