Re: FTGH: Unknown extender card

[Cliff Miller via cctalk]

I once owned a Motorola D2 kit with 6800 micro.  I thought that pin count
sounded familiar.

On Sun, Mar 4, 2018 at 7:52 AM Robert via cctalk 
wrote:

> On Sun, Mar 4, 2018 at 6:40 AM, Noel Chiappa via cctalk
>  wrote:
>
> > A couple of people have replied privately telling me it's for a Motorola
> > EXORbus/EXORciser.
>
> Wasn't EXORbus keyed? I don't see a keyway in the photo.
>
> Robert
>
-- 
Cliff Miller
clif...@gmail.com

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

Heathkit card cage with DEC cards available

[Paul Anderson via cctalk]

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

Re: FTGH: Pair of unknown extender cards

[Fritz Mueller via cctalk]

> On Mar 4, 2018, at 11:09 AM, Noel Chiappa via cctalk  
> wrote:
> OK, another pair of unknown extender cards:

Spring cleaning, Noel? :-)

FTGH: Pair of unknown extender cards

[Noel Chiappa via cctalk]

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

Re: Some fun: who can identify this ?

[Bob Rosenbloom via cctalk]

On 3/4/2018 10:26 AM, Adrian Stoness via cctalk wrote:

some sorta drawer doubht its a chad catcher with a hole for a handle
as for what its from  no idea

On Sun, Mar 4, 2018 at 11:54 AM, Paul Koning via cctalk <
cctalk@classiccmp.org> wrote:


Chad catcher from a PC05 paper tape punch?

 paul


On Mar 4, 2018, at 12:40 PM, Pete Lancashire via cctalk <

cctalk@classiccmp.org> wrote:

https://photos.app.goo.gl/ww7KPnPVexGJiqyE3


Sorta of looks like the chip (chad) box for an IBM 026 or 129 keypunch.


Bob

--
Vintage computers and electronics
www.dvq.com
www.tekmuseum.com
www.decmuseum.org

Re: Some fun: who can identify this ?

[Paul Koning via cctalk]

Chad catcher from a PC05 paper tape punch?

paul

> On Mar 4, 2018, at 12:40 PM, Pete Lancashire via cctalk 
>  wrote:
> 
> https://photos.app.goo.gl/ww7KPnPVexGJiqyE3

Some fun: who can identify this ?

[Pete Lancashire via cctalk]

https://photos.app.goo.gl/ww7KPnPVexGJiqyE3

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: FTGH: Unknown extender card

[Al Kossow via cctalk]

It's too wide.


On 3/4/18 4:40 AM, Noel Chiappa via cctalk wrote:

> A couple of people have replied privately telling me it's for a Motorola
> EXORbus/EXORciser.
> 
>   Noel
> 

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  on behalf of Nico de Jong via 
cctalk 
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" 
To: "General Discussion: On-Topic and Off-Topic Posts"

Sent: Sunday, March 04, 2018 3:52 PM
Subject: EF50 was Re: radar history


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

--
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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" 
To: "General Discussion: On-Topic and Off-Topic Posts" 

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 
http://www.spamfighter.com/SLOW-PCfighter?cid=sigen

Re: EF50 was Re: radar history

[Nico de Jong via cctalk]

.. also known as Noval base
/Nico
- Original Message - 
From: "ANDY HOLT via cctalk" 
To: "General Discussion: On-Topic and Off-Topic Posts" 

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 
http://www.spamfighter.com/SLOW-PCfighter?cid=sigen

Re: FTGH: Unknown extender card

[Jules Richardson via cctalk]

On 03/03/2018 04:48 PM, Noel Chiappa via cctalk wrote:

Hi, I'm not sure what kind of system this extender card


I suppose there's a chance that it's for a piece of test equipment or 
something more analog in nature, and not computer at all - all sorts of 
equipment in the '60s had a card/backplane approach, and presumably field 
engineers would have used riser boards along the lines of this one to 
service them.

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: FTGH: Unknown extender card

[Robert via cctalk]

On Sun, Mar 4, 2018 at 6:40 AM, Noel Chiappa via cctalk
 wrote:

> A couple of people have replied privately telling me it's for a Motorola
> EXORbus/EXORciser.

Wasn't EXORbus keyed? I don't see a keyway in the photo.

Robert

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: FTGH: Unknown extender card

[Noel Chiappa via cctalk]

> 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