[...]
as
took
~30MHz, Yes. Got this particular Rx from a radio amateur who during WW11 repaired the CH equipment. Other than him telling me it was used as a monitoring Rx (120-520MHz) within the CH system, I've never come across any other info. For this kind of kit though I've learned to leave the options open. Only recently discovered an unusual SW set I have, was built specifically to support the (pre radar) acoustic 'sound ranging' systems passively listening across the English channel.
Now that I'm in my office, I can look at the Buderi book. Indeed it has some interesting stuff: from page 117 (near the bottom),
"From that point, it did not take long to identify the Brisith receiver's silicon crystal detectors as the main factor behind its superior showing. The Radlab radar employed a grounded grid triode. The finding stunned the Americans, since they ahd started with crystals but abandoned them earlier in the year after tests showed vacuum tubes to be superior. Only later, Ramsey related, did it become apparent that the crystal used for the American tests had partially burned out. The British, by contrast, had gone with crystals from the start. By spring 1941, Oliphant's lab had designed a better capsule that lessened susceptibility to shock and vibration, and rendered crystals superior to anything in the United States; these had gone into mass production at British Thomson-Houston. Around the same time the duplexing, or TR, problem was solved by the ingenious application of a reflex klystron, itself an adaptation of the Varian brothers' original creation. The so-called soft Sutton tube was filled with a low-pressure gas that was rapidly ionized by the transmitter pulse, providing a short circuit that protected the crystal from burnout. Once the pulse ended, the gas recovered, allowing received signals passage to the detector."
There's a nice section at pages 314-320 covering the discovery of the silicon P-N junction.
Cheers, Tom
Not only that it was germanium not silicon.
Do you have a solid reference for that? "Credible" references I found said they were silicon.
All my references say that the 1N23 is a silicon point-contact (Schottky) diode. MicroMetrics still makes them - at insane prices - and theirs are definitely silicon.
Some of the WWII vintage mixer diodes are impressive. Vf was typically about 250 mV at 1 mA, and junction capacitances were a couple of tenths of a pF, about as good as any packaged diode you can buy today.
John
Early 40's, actually. It was widely used as a radar mixer in WWII.
John
MIT RadLab books, volume 15, "Crystal Rectifiers", appendix D, published in 1948.
What is the citation for your statement that "The 1N23 didn't appear until the '50's, I believe." ?
John
The most conclusive evidence i know of, is someone here who actually put one to test and the result was germanium. A heck of a lot of "official" or "authoritative" records are pure fertilizer.
What test?
John
I'd chock that one up to undecided.
There were 1N23A's B's, C's, and maybe D's. 1N23, A and B were wartime parts. Could have been C+ they were talking about. Or maybe they were just wrong.
John
Smart-ass ping-pong plonked... no redeeming social value ;-)
...Jim Thompson
You mean facts, as opposed to second-hand rumors you think you remember? Guilty as charged.
John
Certainly not. Those were conjectures on why you might have thought that these parts were new in the 1950's. As if it matters.
Those words do usually imply conjecture, yes.
If it's so important to you to be right, you might consider checking facts before posting. But do whatever's fun.
Nope, too much work. The books are widely available.
John
Have something to add? Share your thoughts — no account required.
Ask the community — no account required