> From: William Donzelli
> Germany often gets the short end of the stick when it come to radar
> tech in World War 2
For those who are interested in German radar, there's a good book:
David Pritchard, "The Radar War: Germany's Pioneering Achievement
1904-45", 1989
which covers their systems in some detail. There's also:
Martin Streetly, "Confound and Destroy: 100 Group and the Bomber
Support Campaign", 1978
which contains a very interesting chapter about an exercise called "Post
Mortem", run immediately after the close of hostilities, from 25 June to 7
July, 1945, in which the Allies observed (from inside) the workings of the
German air warning network, including things like how well it coped with
various kind of jamming (window, as well as active).
Noel
> From: Chuck Guzis
> the magnetron was made out to be a super-secret device, yet there's a
> clear explanation of it in my 1942 "Radio Handbook".
Ordinary magnetrons had indeed been around for a while; they were invented in
1920. The British invention was the _cavity magnetron_, a quite different
beast; it was kind of a cross between a magnetron and a klystron, with the
best features of each.
Buderi (which is indeed an excellent history, perhaps the best in the radar
section of my library) has a good explanation of how it works.
Noel
I recently found a Heathkit card cage ( 85-2001 121476 on backplane ) with
a DEC M7270, M8044, M7946, and M8043. I still have a few Heathkit boards
buried here sonewhere.
Please contact me off list if you have any questions or wish to make an
offer.
Thanks, Paul
> From: Fritz Mueller
> Spring cleaning, Noel? :-)
Yeah, sort of! These came with a bunch of PDP-11 boards I bought on eBay,
and they're just clutter. More stuff coming soon!
Noel
OK, another pair of unknown extender cards:
http://ana-3.lcs.mit.edu/~jnc/tech/jpg/tmp/LargeExtender.jpg
If anyone has a use for one or both, FTGH.
They are 17"x10", and the support arms (nice touch) are about 3" long.
No identifying marks that I can perceive, alas. The power leads are titled
"+5", "+12 Handler", +12 Return", "+12 Scan", "+15", "+- 15 Return", "-15".
Noel
> From: Brian Marstella
> I have a CPU board with similar format that I bought thinking I'd
> eventually figure it out.
A couple of people have replied privately telling me it's for a Motorola
EXORbus/EXORciser.
Noel
Hi all, I have an extra "RX8/RX11 floopy disk system user's manual" I'd like
to trade off for something I'd find useful (anything PDP-11 which I don't
already have, preferably). Anyone?
Noel
> From: Jon Elson
> if they did air raids over France or Germany, that eventually a plane
> with one would get shot down and a magnetron would be obtained in
> relatively good shape. So, likely by 1942 it was considered to no
> longer be a secret.
One was lost near Rotterdam in a raid on Cologne on February 2, 1943 (only
the second raid of the war using centimetric H2S radar which used the cavity
magnetron), and the remains were discovered in relatively good shape by
German technicians. The Germans worked out what it did pretty quickly, and by
the fall of 1943 they had started to deploy microwave detector systems.
Noel
