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electronics like its 1922

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TimFox:
jonpaul:
I just finished reading a newly-published history of the "rise of American intelligence" from WW I through WW II to the beginning of the Cold War:  Nicholas Reynolds, "Need to Know", Mariner 2022.
Unfortunately for my interests, the technology is mentioned only in historical context, with brief mentions of "business machinery" supplied by IBM and AT&T for cryptology.
The voice scrambler is not even in the index, but pp 245-246 describe a typical bureaucratic fight (in Washington) when the visiting Alan Turing, there to describe Enigma to US Army and Navy Intelligence, wanted to see the prototype scrambler.
The book mentions that the scrambler development was a joint project between the Army and Navy, done at Bell Laboratories.
I'm going to look through the bibliography for recent works that discuss the technology of that era in more detail (aside from Enigma, which has been discussed in great detail).

jonpaul:
Tim, the 470 k is in the correct placement as a decay time constant.

Yes it is a voltage doubler in the lower right

Search for SIGSALY in NSA, NCM, IEEE SPECTRUM, cryptomuseum.org

The Cryptologic theory and design of SIGSALY was at BTL, Claude Shannon, Nyquist, Blackman....

Turing visited BTL well after the first SIGSALY deployment, to evaluate for use by the UK.

He confirmed Shannon's unbreakable voice scrambling system.

As UK wanted it's own scrambler, Turing designed Delilah, but it was unworkable and only a prototype was made, post war.

to bust another myth, first crack of Enigma keys was not by Turing but three Polish mathématiques at University of Poznan, 1932.

Cryptographically Yours,

Jon

TimFox:
The book I just read concentrated on American intelligence agencies, but did describe the origins of the Enigma decryption in Poland when discussing the co-operation between US and UK cryptology.
(A detail from that book: much of the American equipment built from the Enigma information supplied by UK was built by National Cash Register:  lots of mechanical wheels and stuff.)
One achievement of the US before entering the war was the US Navy's breaking of the "Purple" code used by Japanese diplomats.
Although the US had no useful agents on the ground in the Nazi government, they had something better:  the Japanese ambassador to Berlin was perhaps more Nazi than the Germans, spoke perfect German, and was a close confidant of Hitler.
The US read his dispatches back to Tokyo, including after he inspected the upcoming battlefield in Normandy.
Meanwhile, the Soviet Union had Sorge in Tokyo, but didn't share much of his intelligence with the US.

bsfeechannel:

--- Quote from: TimFox on October 28, 2022, 10:57:54 pm ---I had some quite old crocodile clips on the test leads for a pre-war Simpson 260 meter.
The rubber insulation used on the clips and the wires had hardened with age and cracked off.

--- End quote ---

So, it would be quite improbable to get an intact insulation produced in the 1920s. But, if by anachronistic you mean not produced in the 1920, so are the tubes, produced well into the 21st century.    :-//

TimFox:
Avoiding "anachronism" in this context does not imply that all objects and props must be made in the original century.
Note the use of accurate replicas of harpsichords and krummhorns in authentic performances of 16th-century music.
A true anachronism is the mention of clock chimes in Shakespeare's Julius Caesar.

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