[time-nuts] Fwd: HP5061B Versus HP5071 Cesium Line Frequencies

jimlux jimlux at earthlink.net
Sat Jun 3 20:18:52 EDT 2017

On 6/3/17 2:38 PM, Poul-Henning Kamp wrote:
> --------
> In message <CABXq0ZCZLhBjpZwt+JTXTgR+xGPraO9x9ewKWXs+JAYe2h87Sw at mail.gmail.com>
> , "Donald E. Pauly" writes:
>> Electronic thermal coolers did not exist then
> http://www.thermoelectrics.caltech.edu/thermoelectrics/history.html

I'm not sure about fancy coolers.. Yeah, people showed that the effect 
worked, but I think they really didn't come into their own until the 
modern ones that are omnipresent in 12V powered beer coolers and the 
like were developed.  That was 70s according to the article.
Borg Warner (of clutch, brake, and gearbox fame) apparently had one in 

So they existed, but were pretty exotic. would a crystal oscillator 
builder have wanted to fool with one?  Hey, there have been people 
tinkering with almost everything forever.

>> Electronic temperature sensors did not exist either.
> https://en.wikipedia.org/wiki/Resistance_thermometer#History

Yep... and thermocouples have been used for thermometry for a long time 
too. Thermistors, for that matter, nonlinear as all get-out, but readily 

In the 50s, a *transistor* oscillator would have been pretty unusual. 
I'm not sure they could work at a high enough frequency.  You'll note 
that the early "transistor radios" were basically TRF designs for the AM 
band, and the transistor basically provided audio gain, not RF gain.


I guess the regen receiver must have had some gain at 1 MHz. I found an 
old GE datasheet that gives the ft of 0.6 MHz. (and the hfe wasn't bad, 
20, at DC, probably)

But you sure weren't building a 5MHz or 10 MHz oscillator with a 2N107 
or a CK722.  Or the 2N170 NPN, which I am surprised to find you can 
still buy (and cheaper, in constant dollars, than originally).

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