[time-nuts] AN/URQ13 reference AT cut crystal?

[Bob kb8tq]

Hi

> On Feb 17, 2021, at 11:08 AM, Magnus Danielson <magnus at rubidium.se> wrote:
> 
> Hi Tom,
> 
> On 2021-02-17 16:24, Tom Van Baak wrote:
>> See pages 20-29 in the Mar-1981 HPJ for the "new SC-cut" 10811
>> article(s):
>> 
>> https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1981-03.pdf
>> 
>> It talks about 10544A/C/B and 10811A/B in detail. It compares AT/BT/SC
>> cuts.
>> 
>> Read especially "The SC Cut, a Brief Summary" on page 22.
> 
> Thanks for reminding us of this HPJ.
> 
> In here it is also noted that the 10544 is a BT cut, and this comes to
> contrast that HP never come clean with which cut was used, as some have
> said. Here we have some clear evidence.

Indeed, once they no longer were *using* the BT cut, they would talk about it.


> 
> Also note that it traces the SC-cut back to 1974, and that the same cut
> also been called TTC and TS in early papers. It's interesting to note
> that HP had double-angle cut machines since 1965, so the new cut did not
> caused them a big challenge.

Depends on what you call a big challenge. Gear that actually could cut an 
SC with > 1% yields was indeed very much “in the future” back the early
1970’s. It continued to be somewhat rare through the early 1980’s. 

Bob


> Exactly which double-angle cut's they did
> before SC remains to be found.
> 
> It is however interesting. They also refer to early papers in page 22
> and 23.
> 
> Cheers,
> Magnus
> 
> 
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