Re: Re: radar history Going though my father's Army papers there is a Certificate for his attendance at SCR 268 School!

[Ed Sharpe via cctalk]

Going though my father's Army papers there is a Certificate  for  his 
attendance  at SCR 268 School!


Never  though I would have some  family history to put  with some of the scraps 
 I  have   268 stuff here.   My  dad  was like  some of the others if  it  was 
classified  when he  was in the service  he  tended to continue to think of it 
that  way.  He  mentioned  Radars and ones  with big bed spring antennas  and  
of  course   explained  how  one  worked  when we  moved to a  place with a  
Nike  radar  site across the street  ( LA-55  Palos Verdes)...
 
But  Darn!  wish  he  had   gone into more  detail.
 
I have  2


  of the  scopes  of the  3   Navy Nick   photoed another at a ham fest  but  
he  did not  know I was looking  for a  third..   the shipping  would have been 
 tough... but ...   the  big thing though  with all of them that I have seen  
surplus is they are missing the outer skin  for the  case.  anyone  got  some?
 
we  do have at  SMECC  the complete  IFF  unit that was  used alongside the  
268  it weights 400 lbs  or something...  
 
Now... I  am even moreso wanting to get  mor  268 stuff to  display.   anyone  
have   the TX  RX  units?
 
I am now  going to  find a  nice  frame   for this  certificate.
 
Ed Sharpe archivist  for SMECC 


 

Re: radar history

[Noel Chiappa via cctalk]

> From: Steven Malikoff

> I also have a book 'RADAR How it all began' by Jim Brown ...
> incredibly precise recollection of the engineering 

Wow, thanks for that incredibly valuable pointer. My copy just arrived, and
it's fabulous; it documents in great detail a part of the story that's
little-known, which is the industrialization of the early radar work. There
are a number of books from people on the research side (Watson-Watt, Bowen,
etc), but not much on the industrial side.

There is an obscure book:

Frank Rowlinson, "Contribution to Victory: An Account of Some of the
Special Work of the Metropolitan-Vickers Electrical Company Limited
in the Second World War", Metropolitan-Vickers Electrical Company,
Manshester, 1947 

(which covers a lot of stuff, not just the radar work), but it doesn't have a
lot of technical detail. What it _does_ have a lot of large, excellent B+W
photos of the early CH, CHL etc transmitters (which MetroVick built), but not
much technical detail of them. That book, and Brown's book, are a marvellous
pairing, since he has the detailed description, but no images! A very
complementary pairing.

Noel

Re: EF50 was Re: radar history

[Christian Corti via cctalk]

On Mon, 5 Mar 2018, Christian Corti wrote:

The EF50 has a Loctal base with eight pins. 5xx is Magnoval. 8x is Noval.


Correction: Loctal with nine pins ;-) How crazy...

Christian

Re: EF50 was Re: radar history

[Christian Corti via cctalk]

On Sun, 4 Mar 2018, Nico de Jong wrote:

E = 6.3v filament
F = Pentode
5x = B9G base

.. also known as Noval base


No, absolutely not ;-)
The EF50 has a Loctal base with eight pins. 5xx is Magnoval. 8x is Noval.

Christian

Re: EF50 was Re: radar history

[Noel Chiappa via cctalk]

> 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

Re: EF50 was Re: radar history

[William Donzelli via cctalk]

:> The high frequency power tubes were required for better spacial
resolution. My understanding was that major difference between the
German radar and allied was that the Germans had a single trace, like
a time domain reflectometer. The allies had a rotating image that is
similar to what we see on current radars, today.

Both sides had the displays you describe. The first is called A-scope,
and the latter PPI (Plan Position Indication). Consider that early
radar, well into the 1950s, was actually pretty horrible. PPI back
then often resulted in a screen full of indistinct smudges, so nearly
every search radar had the "old" A-scope, where the operator would use
a cursor* and get a very accurate range and azimuth reading.
Basically, the PPI scope was good for "the big picture" "show me all
the information", and the A-scope was good for getting the information
that was actually useful.

> The cavity tuned magnetron was clearly an issue because it allowed them to 
> run at a higher frequency than the split plate magnetron. Both were 
> significant changes in how things were done.

Significant, but only sometimes significant. Higher frequencies
produced by magnetrons were useful for bombing and gun laying (anti
aircraft and naval guns) as it improved range accuracy greatly, but it
did nothing for air search radars. VHF radars (with triodes) were
still in front line service until the 1950s, simply because they did a
much better job at illuminating aircraft.  Germany often gets the
short end of the stick when it come to radar tech in World War 2, but
towards the end, their (non-magnetron) air search radars were some of
the best. Why? Because that is what they needed with their skies full
of Allied bombers.

The graphical real-time cursor and joystick, in one or two dimensions,
has its origin in World War 2 radar systems. It is astonishing how
many historical accounts of early computer graphics do not mention
this.

--
Will

Re: radar history

[William Donzelli via cctalk]

> The one described in the RH is a "split anode magnetron".   The note on
> it says that "frequency stability is not very good:.

Yes, but in World War 2 (and a little into the 1950s), split anode
magnetrons were used in ECM "jammer" transmitters.

> It's my understanding that the allies used the cavity magnetron and the
> axis used klystrons for their transmitters.

The Germans only used cavity magnetrons in a few radars towards the
end of the war. Post 1943 or so, with the air war flipped with Germany
of the defensive, microwave radar really was not a big advantage to
them. Nearly all German radars used triodes, which worked fine for the
VHF air search radars they needed. They could have used magnetrons for
better gun laying radars for antiaircraft use, but the UHF radars they
had were actually pretty good (FuMG 39 Wurzburg and related).

The Japanese used cavity magnetrons for some of their Naval radars,
but they were hampered by poor receivers.

--
Will

Re: radar history

[William Donzelli via cctalk]

> A very interesting story in this radar history is how the Dutch managed to
> rescue the EF50 tube, essential for these early radar receivers, to England
> just hours before the Germans invaded holland.

This is generally a good article, but has a major flaw or two.

One, it describes acorn tubes as costly and difficult to build. This
was certainly true in Britain and Europe - for some reason the
overseas makers had a very difficult time getting acorns to work (and
last) properly. This was not the case for RCA - there were large
numbers in service by 1939. RCA must have kept the "secret" to making
acorns tight to their chest.

Two, it poorly describes (almost not at all, actually) the Sylvania
loctal that came before the EF50. Most of what makes an EF50 can be
found in the loctal series. US radars generally did not use loctals
(some IFF transponders did - a related technology), but by 1940, the
loctal was pretty obsolete and the 7 pin miniature banging on the
door.

--
Will

Re: radar history

[William Donzelli via cctalk]

> 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.

The cavity magnetron was invented by a lot of people (Soviet,
Japanese, German, Swiss, United States, and I think the Danish*), just
like radar itself. Most of these inventors fell to the wayside,
because the cavity magnetron just was not a useful device. Most of
these inventors tried to use the cavity magnetron as a CW oscillator,
and in that mode, they are basically awful tubes. Randall and Boot
("the British") invented the pulse operation of the cavity magnetron -
a way to basically abuse the tubes but get pulses magnitudes more
powerful than previously done. This, of course, was the key to
microwave radar.

* much of this original research was not secret, just ignored. RCA's
"split anode tank magnetron" was even completely described in one of
their tech journals.

--
Will

Re: radar history

[William Donzelli via cctalk]

> I dunno about these historical accounts.

Radar tech history is a real minefield, and my advice is to take any
historical accounts or studies that are older than ten or fifteen
years old with a grain of salt. Often a big grain.

"History is written by the victors" had been very strong with radar
history, and many people, sometimes in highly regarded academic
positions, are still believing and relaying bad information. It is
only fairly recently that there has been high quality research done.
Some may call it revisionism - but for the most part, much has been
shown as true using verified sources.

Anyway, I am bored tonight, so I think I might spend it here, since
there is a "lot of wrong" in this thread.

--
Will

Re: Re: Re: Re: radar history

[Ed Sharpe via cctalk]

that is precious!
Ed#
 
In a message dated 3/4/2018 7:05:35 AM US Mountain Standard Time, d...@db.net 
writes:

 
 On Sun, Mar 04, 2018 at 12:45:10PM -, Dave Wade via cctalk wrote:
> > 
> > A very interesting story in this radar history is how the Dutch managed to
> > rescue the EF50 tube, essential for these early radar receivers, to England
> > just hours before the Germans invaded holland.

I heard this story.

"It was in Canada though, in 1956, that Watson-Watt got a glimpse of a less
 popular application for the technology he helped develop - when he was
 pulled over for speeding by a policeman using a radar gun.

According to Mr Herriot: "He said, 'My God, if I'd known what they were
going to do with it, I'd have never have invented it!'"
"

http://www.bbc.com/news/uk-scotland-tayside-central-27393558

Diane
-- 
- db@FreeBSD.orgdb@db.nethttp://www.db.net/~db

Re: EF50 was Re: radar history

[dwight via cctalk]

The high frequency power tubes were required for better spacial resolution. My 
understanding was that major difference between the German radar and allied was 
that the Germans had a single trace, like a time domain reflectometer. The 
allies had a rotating image that is similar to what we see on current radars, 
today. The cavity tuned magnetron was clearly an issue because it allowed them 
to run at a higher frequency than the split plate magnetron. Both were 
significant changes in how things were done.

Dwight



From: cctalk <cctalk-boun...@classiccmp.org> on behalf of Nico de Jong via 
cctalk <cctalk@classiccmp.org>
Sent: Sunday, March 4, 2018 7:23:13 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: EF50 was Re: radar history

Oh sh..l., It was a bit too quick
Apologies...
/Nico
- Original Message -
From: "ANDY HOLT via cctalk" <cctalk@classiccmp.org>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk@classiccmp.org>
Sent: Sunday, March 04, 2018 3:52 PM
Subject: EF50 was Re: radar history


>E = 6.3v filament
> F = Pentode
> 5x = B9G base
>
> Andy

--
I am using the free version of SPAMfighter.
SPAMfighter has removed 16135 of my spam emails to date.
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Re: EF50 was Re: radar history

[Nico de Jong via cctalk]

Oh sh..l., It was a bit too quick
Apologies...
/Nico
- Original Message - 
From: "ANDY HOLT via cctalk" <cctalk@classiccmp.org>
To: "General Discussion: On-Topic and Off-Topic Posts" 
<cctalk@classiccmp.org>
Sent: Sunday, March 04, 2018 3:52 PM
Subject: EF50 was Re: radar history


>E = 6.3v filament
> F = Pentode
> 5x = B9G base
>
> Andy 

--
I am using the free version of SPAMfighter.
SPAMfighter has removed 16135 of my spam emails to date.
Get the free SPAMfighter here: http://www.spamfighter.com/len

Do you have a slow PC? Try a Free scan 
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Re: EF50 was Re: radar history

[Nico de Jong via cctalk]

.. also known as Noval base
/Nico
- Original Message - 
From: "ANDY HOLT via cctalk" <cctalk@classiccmp.org>
To: "General Discussion: On-Topic and Off-Topic Posts" 
<cctalk@classiccmp.org>
Sent: Sunday, March 04, 2018 3:52 PM
Subject: EF50 was Re: radar history


>E = 6.3v filament
> F = Pentode
> 5x = B9G base
>
> Andy 

--
I am using the free version of SPAMfighter.
SPAMfighter has removed 16135 of my spam emails to date.
Get the free SPAMfighter here: http://www.spamfighter.com/len

Do you have a slow PC? Try a Free scan 
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EF50 was Re: radar history

[ANDY HOLT via cctalk]

E = 6.3v filament
F = Pentode
5x = B9G base

Andy

Re: Re: Re: radar history

[Diane Bruce via cctalk]

On Sun, Mar 04, 2018 at 12:45:10PM -, Dave Wade via cctalk wrote:
> > 
> > A very interesting story in this radar history is how the Dutch managed to
> > rescue the EF50 tube, essential for these early radar receivers, to England
> > just hours before the Germans invaded holland.

I heard this story.

"It was in Canada though, in 1956, that Watson-Watt got a glimpse of a less
 popular application for the technology he helped develop - when he was
 pulled over for speeding by a policeman using a radar gun.

According to Mr Herriot: "He said, 'My God, if I'd known what they were
going to do with it, I'd have never have invented it!'"
"

http://www.bbc.com/news/uk-scotland-tayside-central-27393558

Diane
-- 
- d...@freebsd.org d...@db.net http://www.db.net/~db

RE: Re: Re: radar history

[Dave Wade via cctalk]

> 
> A very interesting story in this radar history is how the Dutch managed to
> rescue the EF50 tube, essential for these early radar receivers, to England
> just hours before the Germans invaded holland.
> 
> Read here ( not my site ):
> 
> http://www.dos4ever.com/EF50/EF50.html#war
> 
> Jos

Williams and Kilburn who built the Manchester Baby (SSEM) had worked on Radar 
during the Second World War.  
The Store, being composed of CRT tubes uses many circuits cribbed from Radar. 
The machine contains 156 EF50s 

http://computerconservationsociety.org/ssemvolunteers/volunteers/valvetypes.htm 

the store amplifiers which detect if there is a "dot" or a "dash" on the face 
of the Kilburn-Williams tube use 4 x EF50 and 1 x EF55

http://computerconservationsociety.org/ssemvolunteers/volunteers/storecrt-amp.html

Dave

Re: Re: Re: radar history

[Ed Sharpe via cctalk]

I mean TUBE  not  tune!
These look like  red  tune in  ww2 lend  lease talk  radio that has a vhf  
section?  Ed# 
 
In a message dated 3/3/2018 4:02:34 PM US Mountain Standard Time, 
cctalk@classiccmp.org writes:

 
 These look like  red  tune in  ww2 lend  lease talk  radio that has a vhf  
section?  Ed# 
 
In a message dated 3/3/2018 3:28:48 AM US Mountain Standard Time, 
cctalk@classiccmp.org writes:

 
 On 03.03.2018 09:35, Paul Birkel via cctalk wrote:
> On Sat, Mar 3, 2018 at 12:46 AM, Chuck Guzis via cctalk <
> cctalk@classiccmp.org> wrote:
> 
>> I dunno about these historical accounts.
>>


A very interesting story in this radar history is how the Dutch managed to 
rescue the EF50 tube, essential for these early radar receivers, to England 
just hours before the Germans invaded holland.

Read here ( not my site ):

http://www.dos4ever.com/EF50/EF50.html#war

Jos

Re: Re: radar history

[Ed Sharpe via cctalk]

These look like  red  tune in  ww2 lend  lease talk  radio that has a vhf  
section?  Ed# 
 
In a message dated 3/3/2018 3:28:48 AM US Mountain Standard Time, 
cctalk@classiccmp.org writes:

 
 On 03.03.2018 09:35, Paul Birkel via cctalk wrote:
> On Sat, Mar 3, 2018 at 12:46 AM, Chuck Guzis via cctalk <
> cctalk@classiccmp.org> wrote:
> 
>> I dunno about these historical accounts.
>>


A very interesting story in this radar history is how the Dutch managed to 
rescue the EF50 tube, essential for these early radar receivers, to England 
just hours before the Germans invaded holland.

Read here ( not my site ):

http://www.dos4ever.com/EF50/EF50.html#war

Jos

Re: Re: radar history

[Ed Sharpe via cctalk]

Noel - the MIT rad labs  thick  volume on the Maggie  is  pretty  cool  too..
We are blessed to have  an entire set ( 28 volumes) at the museum of   rad 
labs...  I also have a  set myself... with  used to be a lot more special  than 
now   you can download   them in digital  form and they float on cd  too  
 
We  do have  some  volumes that  may be  extra at the museum library  some 
things are  just  so nice on paper... this is one   one of the others is a 
set of Bell System Technical  Journals... ( will probably have  an  extra  set 
of those..  many many boxes...
 
got coutermeasures  I recommend  the  2  volume  set   from Harvard Radio 
Research Labs     ala  RRL   ( Terman ran it)  
 
Salsbury,  whose  entire  library is inside the museum library  started at   
MIT Rad Las as he  came over  rith  EOL  from Berkeley and  went  over to 
Harvard and  was  section head on the 50,000 watt..  UHF ground jammer   for 
Lichtenstein    Nazi  night fighter radar...
 
we have some radar  gear and a lot  of   countermeasures   gear...
 
 
In a message dated 3/3/2018 6:35:14 AM US Mountain Standard Time, 
cctalk@classiccmp.org writes:

 
 > 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

Re: radar history

[Noel Chiappa via cctalk]

> 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

Re: radar history

[Chuck Guzis via cctalk]

On 03/03/2018 12:58 AM, Ed Sharpe via cctalk wrote:
> OK or may have been a magnetron... but not a cavity magnetron I
> gave a 30s radio news as I remember had magnetron.. but not cavity
> one.. I was confused  by it at the time, but someone older explained
> it to me OK see some maggIes,from 32... but notch SECRET CAVITY
> MAGNETRON
> 
> http://www.magazineart.org/main.php/v/technical/radionews/RadioNews1932-06.jpg.html

The one described in the RH is a "split anode magnetron".   The note on
it says that "frequency stability is not very good:.

There's also a discussion of the RCA 825 klystrode--a sort of klystron
triode hybrid.

It's my understanding that the allies used the cavity magnetron and the
axis used klystrons for their transmitters.

--Chuck

Re: radar history

[Jon Elson via cctalk]

On 03/03/2018 12:46 AM, Chuck Guzis via cctalk wrote:

I dunno about these historical accounts.

I was watching a PBS program about RADAR and the magnetron was made out
to be a super-secret device, yet there's a clear explanation of it in my
1942 "Radio Handbook".

I think the British considered it top secret in about 1939, 
but they knew 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.


Jon

Re: radar history

[Ed Sharpe via cctalk]

OK or may have been a magnetron... but not a cavity magnetron I gave a 30s 
radio news as I remember had magnetron.. but not cavity one.. I was confused  
by it at the time, but someone older explained it to me OK see some 
maggIes,from 32... but notch SECRET CAVITY MAGNETRON

http://www.magazineart.org/main.php/v/technical/radionews/RadioNews1932-06.jpg.html

AND see this article




How to Construct a 56 Megacycle Magnetron Transmitter
September 1932 Radio News Article
September 1932 Radio News
 September 1932 Radio News Cover - RF Cafe[Table of Contents]
Wax nostalgic about and learn from the history of early electronics. See 
articles from Radio & Television News, published 1919 - 1959. All copyrights 
hereby acknowledged.
Magnetrons are fairly ubiquitous in society these days for use in heating, 
radar, and even lighting. They were probably the first useful means of 
producing high power microwave signals. The concept was first brought to 
fruition in the early 1920s as a laboratory curiosity and rapidly developed 
into a practical type of device with many applications and spin-off products 
like the klystron, the traveling wave tube, and the cross-field amplifier. This 
article from a 1932 edition of Radio News reports on the state of the art a 
decade after the magnetron's inception.
How to Construct a 56 Megacycle Magnetron Transmitter
Here it is, something new in radio! A new oscillator principle for the 
ultra-short waves employing the gridless double plate tube in a manner 
comparable in many respects to the Gill-Morill method. This article, a feature 
of the Radio News series on opening up the ultra-short wave field, will be 
invaluable to the technician and earnest experimental amateur
By James Millen
 
 The High C Tuner - RF Cafe
The High C Tuner
Figure 10. This is the tuned circuit for resonating the new magnetron 
oscillator tube as explained in the text.
 The Magnetron - RF Cafe
The Magnetron
Figure 1. The tube which with its field coil offers new fields of 
experimentation on the ultra-short waves. 
The American amateur was the first to make practical use of the 200-meter band 
and the first to develop the utility of still shorter and vastly more important 
communication channels. A new field of research, the ultra-short waves, now 
challenges his ingenuity, and we are sincere in our belief that here again the 
"ham" will make a genuine contribution to ultra-high-frequency technique. The 
magnetron, in particular, offers fertile possibilities, and its application to 
commercial enterprise may be, to our way of thinking, materially accelerated by 
its exploitation and development in the amateur ranks. This article finds dual 
justification in the effort to stimulate such experimentation, and in 
presenting a practical 56-megacycle magnetron transmitter.
As we pointed out in the original article of this series, there exist a variety 
of methods whereby ultra-short-wave energy can be set in motion. However, the 
necessity for efficiency (reasonably high-power output for practical input 
powers) and stability places a definite limitation on the systems serviceable 
for useful communication. The magnetron, today, offers the most economical 
method for generating quasi-optical power. As it is an electronic device, its 
functioning is perhaps best understood by indicating its similarity to more 
conventional systems. It is not particularly difficult to design the usual sort 
of tube oscillators for wavelengths between 5 and 10 meters, and by the 
utilization of their harmonics to extend this range to a still lower minimum. 
However, as might be imagined, the stability of such systems leaves much to be 
desired, and the power output is generally inadequate. Also, as may be readily 
understood, maximum frequency limitations are necessarily imposed by 
considerations of the capacity and inductance by which resonance is determined. 
An additional complication, the fact that as the frequency is still further 
raised the period approaches the times required for the electrons to complete 
their inter-electrode cycle, imposes further limitations - at the same time 
offering a solution to the problem. It was found that, under proper conditions, 
oscillations could be sustained the frequency of which was dependent on the 
geometry of the tube or on the potentials applied to the elements rather than 
upon the LC characteristics of the circuit. Such systems have been described 
categorically as Barkhausen-Kurz circuits in deference to their two 
most-prominent investigators. It is logical and true that such arrangements are 
capable of delivering higher powers, at very short wavelengths, than those with 
which we have become familiar on the conventional short waves. It was also 
discovered that the power output could be increased by resonating the circuit 
to the natural electronic frequency, and such transmitters have come to be 
known as Gill-Morill circuits and are comparable in many 

Re: radar history

[Noel Chiappa via cctalk]

> 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

Re: radar history

[Steve Malikoff via cctalk]

Chuck reckoned
> I dunno about these historical accounts.
> I was watching a PBS program about RADAR and the magnetron was made out
> to be a super-secret device, yet there's a clear explanation of it in my
> 1942 "Radio Handbook".

Yeah I know this off-topic, but what the heck.
The Buderi book mentioned is a great account of the MIT Rad Lab story, ie radar 
from an american
perspective. I have it on my bookshelf and I'd recommend it to anyone.

I also have a book 'RADAR How it all began' by Jim Brown, one of the designers 
of the Chain Home
system working for the Valve Lab of Metropolitan Vickers, who built and ran the 
CH hardware from 1937.

Apart from being a incredibly precise recollection of the engineering ("The 
valve consisted
of a solid copper block about 6 in x 6 in x 4in. ... The 6 in x 6 in faces were 
machined out
about 4 1/2 in diameteer and grooved to take two ceramic tubular insulators 
which were about
4 in outside diameter and 4 in long  and 3/4 in thick. On the end of each 
insulator was the
anode which was a copper plate 1/2 in thick " etc etc etc and the whole 
book is to that
level of detail) it has an interesting and ironic factoid.

The Chain Home 60kW tetrode transmitter tubes were enclosed in boxes about 8 
feet high, 8 feet
wide and 8 feet long made from brass sheet and brass angle. To adjust the tubes 
externally required
an insulator chosen from the allowed group of materials of pure mica, ceramics, 
steatite (soapstone),
Pyrex glass and a substance called Calit.
Calit was a white marble-like material that could be ground to shape and 
drilled, and so was chosen.
It was also imported from Germany :)

Re: radar history

[jos via cctalk]

On 03.03.2018 09:35, Paul Birkel via cctalk wrote:

On Sat, Mar 3, 2018 at 12:46 AM, Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:


I dunno about these historical accounts.




A very interesting story in this radar history is how the Dutch managed to 
rescue the EF50 tube, essential for these early radar receivers, to England 
just hours before the Germans invaded holland.

Read here ( not my site ):

http://www.dos4ever.com/EF50/EF50.html#war

Jos

RE: radar history

[Paul Birkel via cctalk]

On Sat, Mar 3, 2018 at 12:46 AM, Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> I dunno about these historical accounts.
>
> I was watching a PBS program about RADAR and the magnetron was made out
> to be a super-secret device, yet there's a clear explanation of it in my
> 1942 "Radio Handbook".
>
> --Chuck

For a non-sensationalized accounting that tracks developments, and 
personalities, over the course of many decades of developments and spin-offs, 
try:

The Invention That Changed the World:
How a Small Group of Radar Pioneers Won the Second World War and Launched a 
Technical Revolution
(1998; Touchstone; 576 pp)

Authored by Robert Buderi, former technology editor for Business Week.

Yes, quite an over-the-top title ... but the content isn't that way at all, 
IMO.  It stacks up quite well against academic treatises on related topics 
(e.g., Whirlwind) published by MIT Press.

-
paul

Re: radar history

[Adrian Stoness via cctalk]

^^ thats because they create lure around things to install fear in the
enemy remember propiganda


On Sat, Mar 3, 2018 at 12:46 AM, Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> I dunno about these historical accounts.
>
> I was watching a PBS program about RADAR and the magnetron was made out
> to be a super-secret device, yet there's a clear explanation of it in my
> 1942 "Radio Handbook".
>
> --Chuck
>

Re: radar history

[Chuck Guzis via cctalk]

I dunno about these historical accounts.

I was watching a PBS program about RADAR and the magnetron was made out
to be a super-secret device, yet there's a clear explanation of it in my
1942 "Radio Handbook".

--Chuck

Re: radar history

[Ed Sharpe via cctalk]

dunno what that thing is..
Mentioned link as many of us,are,interested in a,cross section on electronivs 
history..  pike Cory, and others ..

Sent from AOL Mobile Mail

On Friday, March 2, 2018 Ian Finder  wrote:


All I have to say in response to this message is...

http://i0.kym-cdn.com/entries/icons/original/000/022/978/yNlQWRM.jpg

Re: radar history

[Ian Finder via cctalk]

All I have to say in response to this message is...
http://i0.kym-cdn.com/entries/icons/original/000/022/978/yNlQWRM.jpg