Some time ago someone very kindly posted some schematics for the tube based
Doppler radar proximity fuses used in anti-aircraft shells.

When I went to look in the folder they should have been in, they were not
there.

It is possible they are in the large volume of downloads I haven't sorted
yet - in which case a reminder of the file names would enable me to search
for them.

A less welcome possibility is that one of the DVD I used to transfer files
from the broadband PC to the archive PC turned out to be a failed copy - if
they were on that they're lost!

Any help appreciated.
TIA.

On Mon, 21 May 2007 20:46:44 GMT, "ian field"
wrote:

Some time ago someone very kindly posted some schematics for the tube based
Doppler radar proximity fuses used in anti-aircraft shells.

When I went to look in the folder they should have been in, they were not
there.

It is possible they are in the large volume of downloads I haven't sorted
yet - in which case a reminder of the file names would enable me to search
for them.

A less welcome possibility is that one of the DVD I used to transfer files
from the broadband PC to the archive PC turned out to be a failed copy - if
they were on that they're lost!

Any help appreciated.
TIA.


I have four schematics around here somewhere. I'll post later today if
I can locate them.

John

ian field wrote:

Some time ago someone very kindly posted some schematics for the tube based
Doppler radar proximity fuses used in anti-aircraft shells.

From what era ?

Graham

"Eeyore" wrote in message
...


ian field wrote:

Some time ago someone very kindly posted some schematics for the tube
based
Doppler radar proximity fuses used in anti-aircraft shells.

From what era ?

Graham


Any vintage, and especially wartime electronics (allied *or* axis) is of
interest, if you have any such schematics I would be pleased to see them.

"John Larkin" wrote in message
...
On Mon, 21 May 2007 20:46:44 GMT, "ian field"
wrote:

Some time ago someone very kindly posted some schematics for the tube
based
Doppler radar proximity fuses used in anti-aircraft shells.

When I went to look in the folder they should have been in, they were not
there.

It is possible they are in the large volume of downloads I haven't sorted
yet - in which case a reminder of the file names would enable me to search
for them.

A less welcome possibility is that one of the DVD I used to transfer files
from the broadband PC to the archive PC turned out to be a failed copy -
if
they were on that they're lost!

Any help appreciated.
TIA.


I have four schematics around here somewhere. I'll post later today if
I can locate them.

John


Thanks, I thought I could locate the ones I downloaded from this group but
apparently I've misplaced them.

It must have been you who supplied them in the first place then.

On Mon, 21 May 2007 21:27:45 GMT, "ian field"
wrote:


"John Larkin" wrote in message
.. .
On Mon, 21 May 2007 20:46:44 GMT, "ian field"
wrote:

Some time ago someone very kindly posted some schematics for the tube
based
Doppler radar proximity fuses used in anti-aircraft shells.

When I went to look in the folder they should have been in, they were not
there.

It is possible they are in the large volume of downloads I haven't sorted
yet - in which case a reminder of the file names would enable me to search
for them.

A less welcome possibility is that one of the DVD I used to transfer files
from the broadband PC to the archive PC turned out to be a failed copy -
if
they were on that they're lost!

Any help appreciated.
TIA.


I have four schematics around here somewhere. I'll post later today if
I can locate them.

John


Thanks, I thought I could locate the ones I downloaded from this group but
apparently I've misplaced them.

It must have been you who supplied them in the first place then.


OK, here they are. These are from Markus' huge black 1971 book
"Electronic Circuits Manual"

Try to find Baldwin's book, "The Deadly Fuze"

John

"John Larkin" wrote in message
...
On Mon, 21 May 2007 21:27:45 GMT, "ian field"
wrote:


"John Larkin" wrote in
message
. ..
On Mon, 21 May 2007 20:46:44 GMT, "ian field"
wrote:

Some time ago someone very kindly posted some schematics for the tube
based
Doppler radar proximity fuses used in anti-aircraft shells.

When I went to look in the folder they should have been in, they were
not
there.

It is possible they are in the large volume of downloads I haven't
sorted
yet - in which case a reminder of the file names would enable me to
search
for them.

A less welcome possibility is that one of the DVD I used to transfer
files
from the broadband PC to the archive PC turned out to be a failed copy -
if
they were on that they're lost!

Any help appreciated.
TIA.


I have four schematics around here somewhere. I'll post later today if
I can locate them.

John


Thanks, I thought I could locate the ones I downloaded from this group but
apparently I've misplaced them.

It must have been you who supplied them in the first place then.


OK, here they are. These are from Markus' huge black 1971 book
"Electronic Circuits Manual"

Try to find Baldwin's book, "The Deadly Fuze"

John




Very many thanks.

ian field wrote:

"Eeyore" wrote:
ian field wrote:

Some time ago someone very kindly posted some schematics for the tube
based Doppler radar proximity fuses used in anti-aircraft shells.

From what era ?

Any vintage, and especially wartime electronics (allied *or* axis) is of
interest, if you have any such schematics I would be pleased to see them.

Well, I recall that early proximity fuses didn't do Doppler but simply relied on
an oscillator being 'pulled' by the target.


Graham

On Mon, 21 May 2007 21:20:53 GMT, Eeyore
wrote:



ian field wrote:

Some time ago someone very kindly posted some schematics for the tube based
Doppler radar proximity fuses used in anti-aircraft shells.

From what era ?

---
The US Revolutionary War, dumb donkey.


--
JF

On Mon, 21 May 2007 21:54:18 GMT, "ian field"
wrote:


"John Larkin" wrote in message
.. .
On Mon, 21 May 2007 21:27:45 GMT, "ian field"
wrote:


"John Larkin" wrote in
message
...
On Mon, 21 May 2007 20:46:44 GMT, "ian field"
wrote:

Some time ago someone very kindly posted some schematics for the tube
based
Doppler radar proximity fuses used in anti-aircraft shells.

When I went to look in the folder they should have been in, they were
not
there.

It is possible they are in the large volume of downloads I haven't
sorted
yet - in which case a reminder of the file names would enable me to
search
for them.

A less welcome possibility is that one of the DVD I used to transfer
files
from the broadband PC to the archive PC turned out to be a failed copy -
if
they were on that they're lost!

Any help appreciated.
TIA.


I have four schematics around here somewhere. I'll post later today if
I can locate them.

John


Thanks, I thought I could locate the ones I downloaded from this group but
apparently I've misplaced them.

It must have been you who supplied them in the first place then.


OK, here they are. These are from Markus' huge black 1971 book
"Electronic Circuits Manual"

Try to find Baldwin's book, "The Deadly Fuze"

John




Very many thanks.


I took these with my ancient floppy-disk Mavica camera. I suppose I
should reshoot these some day at better resolution.

Oh, if any fool tells you that these were not Doppler detectors, well,
ignore them.

John

On Mon, 21 May 2007 19:33:44 -0500, John Fields
wrote:

On Mon, 21 May 2007 22:09:37 GMT, Eeyore
wrote:



ian field wrote:

"Eeyore" wrote:
ian field wrote:

Some time ago someone very kindly posted some schematics for the tube
based Doppler radar proximity fuses used in anti-aircraft shells.

From what era ?

Any vintage, and especially wartime electronics (allied *or* axis) is of
interest, if you have any such schematics I would be pleased to see them.

Well, I recall that early proximity fuses didn't do Doppler but simply relied on
an oscillator being 'pulled' by the target.

---
Wrong again, dumbass.

http://en.wikipedia.org/wiki/Proximity_fuse

To y'alls credit, however, the proximity fuse (and the magnetron)
were invented in the UK.

The British initially concentrated on a photoelectric prox fuze, which
never worked well enough to deploy. They shifted to RF doppler, but
according to my sources none of their designs saw battle. Their later
prototypes, X4 and X5, were based on American components. The US
simply had a lot more resources to put into the problem.

John

John Fields wrote:

So why do you find it necessary to denigrate the US, who kept you
from being swallowed up by Germany? Not once, but twice

Certainly not twice. The USA pretty much only turned up for the celebrations the
first time round.

Why do you find it neceesary to make up lies about the Britsh Empire being run by ppl
with rampant blood-lust whilst we're at it ?

Graham

On Tue, 22 May 2007 03:00:56 GMT, Eeyore
wrote:



John Fields wrote:

So why do you find it necessary to denigrate the US, who kept you
from being swallowed up by Germany? Not once, but twice

Certainly not twice. The USA pretty much only turned up for the celebrations the
first time round.

---
Geez, I guess we had no troops or equipment in Europe the second
time around? Must have been those history books we rewrote that had
me thinking we did.

Thanks for the correction.

Why do you find it neceesary to make up lies about the Britsh Empire being run by ppl
with rampant blood-lust whilst we're at it ?

---
Me???

I'm just quoting Wikipedia. If you have a problem with their
articles take it up with them. Or, better yet, correct the
articles. You're allowed to, you know.


--
JF

John Fields wrote:

Eeyore wrote:
John Fields wrote:

So why do you find it necessary to denigrate the US, who kept you
from being swallowed up by Germany? Not once, but twice

Certainly not twice. The USA pretty much only turned up for the celebrations the
first time round.

---
Geez, I guess we had no troops or equipment in Europe the second
time around? Must have been those history books we rewrote that had
me thinking we did.

Thanks for the correction.

Why do you find it neceesary to make up lies about the Britsh Empire being run by ppl
with rampant blood-lust whilst we're at it ?

---
Me???

I'm just quoting Wikipedia.

No you're not.

There was very little blood spilt in building the Empire btw. It would have been
counter-productive, unsustainable (and quite simply unaffordable) to have had hundreds of
thousands of British troops stationed overseas to subjugate various populations. In fact
the British Army of the time never had that many troops to begin with anyway !

Most of the aquisition of foreign territory which had some existing level of simple
government (even if was only the local ruler such as a sultan, maharajah or nawab ) was
based on defence pacts in return for trade concessions.
http://en.wikipedia.org/wiki/Subsidiary_Alliance

Graham

On Tue, 22 May 2007 11:47:17 GMT, Eeyore
wrote:



John Fields wrote:

Eeyore wrote:
John Fields wrote:

So why do you find it necessary to denigrate the US, who kept you
from being swallowed up by Germany? Not once, but twice

Certainly not twice. The USA pretty much only turned up for the celebrations the
first time round.

---
Geez, I guess we had no troops or equipment in Europe the second
time around? Must have been those history books we rewrote that had
me thinking we did.

Thanks for the correction.

Why do you find it neceesary to make up lies about the Britsh Empire being run by ppl
with rampant blood-lust whilst we're at it ?

---
Me???

I'm just quoting Wikipedia.

No you're not.

There was very little blood spilt in building the Empire btw. It would have been
counter-productive, unsustainable (and quite simply unaffordable) to have had hundreds of
thousands of British troops stationed overseas to subjugate various populations. In fact
the British Army of the time never had that many troops to begin with anyway !

Most of the aquisition of foreign territory which had some existing level of simple
government (even if was only the local ruler such as a sultan, maharajah or nawab ) was
based on defence pacts in return for trade concessions.
http://en.wikipedia.org/wiki/Subsidiary_Alliance

---
All very nice and tidy, but the fact remains that if you wanted
those "trade concessions" and you couldn't get them, then your
reaction would have been to take what you wanted by force. After
all, even a tiny army should be enough to convince a single sultan
to give in without a fight.


--
JF

John Fields wrote:

but the fact remains that if you wanted those "trade concessions" and you couldn't get them,
then your reaction would have been to take what you wanted by force

So tell me more about this.

Graham

"John Larkin" wrote in message
...
On Mon, 21 May 2007 21:54:18 GMT, "ian field"
wrote:


"John Larkin" wrote in
message
. ..
On Mon, 21 May 2007 21:27:45 GMT, "ian field"
wrote:


"John Larkin" wrote in
message
m...
On Mon, 21 May 2007 20:46:44 GMT, "ian field"
wrote:

Some time ago someone very kindly posted some schematics for the tube
based
Doppler radar proximity fuses used in anti-aircraft shells.

When I went to look in the folder they should have been in, they were
not
there.

It is possible they are in the large volume of downloads I haven't
sorted
yet - in which case a reminder of the file names would enable me to
search
for them.

A less welcome possibility is that one of the DVD I used to transfer
files
from the broadband PC to the archive PC turned out to be a failed
copy -
if
they were on that they're lost!

Any help appreciated.
TIA.


I have four schematics around here somewhere. I'll post later today if
I can locate them.

John


Thanks, I thought I could locate the ones I downloaded from this group
but
apparently I've misplaced them.

It must have been you who supplied them in the first place then.


OK, here they are. These are from Markus' huge black 1971 book
"Electronic Circuits Manual"

Try to find Baldwin's book, "The Deadly Fuze"

John




Very many thanks.


I took these with my ancient floppy-disk Mavica camera. I suppose I
should reshoot these some day at better resolution.

Oh, if any fool tells you that these were not Doppler detectors, well,
ignore them.

John


The reminder of the file names helped me find the mislaid copies on my
archive PC - the only proximity fuse document in the correct folder was the
NS application note.

"John Larkin" wrote in
message

Oh, if any fool tells you that these were not Doppler detectors, well,
ignore them.

Jim says the door sensors at the supermarket are doppler too, and they work
even when people are not shot at the door from a canon.

It's even amazing that the shells work that way, since they move at a pretty
small fraction of c.

The time-frames defy logic too. Radar is invented, then it took a couple of
years for miniaturized doppler radar, then another 25 years for doppler
radar on the F14.


--

Reply in group, but if emailing add another
zero, and remove the last word.

"ian field" wrote in message


Any vintage, and especially wartime electronics (allied *or* axis) is
of interest, if you have any such schematics I would be pleased to
see them.

I'd like to soo an allied encryption machine from that time. The enigma is
so well known, and ours must be declassified since new techniques were out a
few years after the war, yet it isn't described anywhere.


--

Reply in group, but if emailing add another
zero, and remove the last word.

"Tom Del Rosso" wrote in message
...
"ian field" wrote in message


Any vintage, and especially wartime electronics (allied *or* axis) is
of interest, if you have any such schematics I would be pleased to
see them.

I'd like to soo an allied encryption machine from that time. The enigma
is
so well known, and ours must be declassified since new techniques were out
a
few years after the war, yet it isn't described anywhere.

The Bletchley Park Trust has reconstructed the Colossus semi-programmable
computer as used to crack Enigma codes.

"Tom Del Rosso" wrote in message
...
snip

The time-frames defy logic too. Radar is invented, then it took a couple
of
years for miniaturized doppler radar, then another 25 years for doppler
radar on the F14.

The phased array radar was being installed into the P3 Orion (at Bangor NAS)
in 1980.

"ian field" wrote in message


The Bletchley Park Trust has reconstructed the Colossus
semi-programmable computer as used to crack Enigma codes.

Yeah, but it's always their codes and our code-breaking. I'm sure we didn't
transmit in the clear.


--

Reply in group, but if emailing add another
zero, and remove the last word.

Tom Del Rosso wrote:
"ian field" wrote in message

The Bletchley Park Trust has reconstructed the Colossus
semi-programmable computer as used to crack Enigma codes.

Yeah, but it's always their codes and our code-breaking. I'm sure we didn't
transmit in the clear.

Well, we sure did with airplanes. Perhaps it wasn't an automated
process during WWII? Single use pads were and are still popular.

NSA has a code museum out at Ft Meade in Maryland. I haven't made
it out there, but I am sure it would contain the answer.

-Chuck

On Wed, 23 May 2007 16:58:20 -0400, Tom Del Rosso wrote:

"ian field" wrote in message


Any vintage, and especially wartime electronics (allied *or* axis) is
of interest, if you have any such schematics I would be pleased to
see them.

I'd like to soo an allied encryption machine from that time. The enigma is
so well known, and ours must be declassified since new techniques were out a
few years after the war, yet it isn't described anywhere.

You haven't Googled it? I recently StumbledUpon a site offering an
electronic version of Enigma. The original Enigma is out there too; it
was patented before the war, so its design was never secret (the secrets
were the wiring and starting positions of the rotors and the settings of
the plugboard).

I would really like to see a detailed description of the cryptanalysis of
the "Purple" cypher that was Japan's answer to Enigma. The American
cryptographers who broke that one built their own logically-equivalent
machine without ever seeing a Purple machine. Then there was the Allied
SIGABA, which, as far as anyone is willing to admit, was never broken. It
used rotors to control the motion of other rotors.

"Stephen J. Rush" wrote in message
news

You haven't Googled it? [.....]

[....]. Then there was the Allied SIGABA, which, as far as anyone
is willing to admit, was never broken. It used rotors to control the
motion of other rotors.

I've googled, but SIGABA never came up. Thanks.


--

Reply in group, but if emailing add another
zero, and remove the last word.

ian field wrote:

"Tom Del Rosso" wrote
"ian field" wrote

Any vintage, and especially wartime electronics (allied *or* axis) is
of interest, if you have any such schematics I would be pleased to
see them.

I'd like to soo an allied encryption machine from that time. The enigma
is so well known, and ours must be declassified since new techniques were
out
a few years after the war, yet it isn't described anywhere.

The Bletchley Park Trust has reconstructed the Colossus semi-programmable
computer as used to crack Enigma codes.

I've just today received an invitation to a tour and lecture at Bletchley and
apparently a demonstration of both Enigma and the reconstructed Collosus.

Graham

On Wed, 23 May 2007 16:54:17 -0400, Tom Del Rosso wrote:
"John Larkin" wrote in
message

Oh, if any fool tells you that these were not Doppler detectors, well,
ignore them.

Jim says the door sensors at the supermarket are doppler too, and they work
even when people are not shot at the door from a canon.

It's even amazing that the shells work that way, since they move at a pretty
small fraction of c.

The time-frames defy logic too. Radar is invented, then it took a couple of
years for miniaturized doppler radar, then another 25 years for doppler
radar on the F14.

No, it took them 25 years to do the F-14. I was in the USAF 1968-1976,
Working mostly on F-4s and B-66s, and Doppler radar was already routine.

Cheers!
Rich

On Wed, 23 May 2007 17:16:51 -0400, Tom Del Rosso wrote:

"ian field" wrote in message


The Bletchley Park Trust has reconstructed the Colossus
semi-programmable computer as used to crack Enigma codes.

Yeah, but it's always their codes and our code-breaking. I'm sure we didn't
transmit in the clear.

Of course not. We translated it to Navaho.

Cheers!
Rich

On Wed, 23 May 2007 18:01:17 -0400, Chuck Harris wrote:
Tom Del Rosso wrote:
"ian field" wrote in message

The Bletchley Park Trust has reconstructed the Colossus
semi-programmable computer as used to crack Enigma codes.

Yeah, but it's always their codes and our code-breaking. I'm sure we didn't
transmit in the clear.

Well, we sure did with airplanes. Perhaps it wasn't an automated
process during WWII? Single use pads were and are still popular.

NSA has a code museum out at Ft Meade in Maryland. I haven't made
it out there, but I am sure it would contain the answer.


Don't you people know how to operate Wiki?
http://en.wikipedia.org/wiki/Enigma_machine

Cheers!
Rich

On Wed, 23 May 2007 18:01:22 -0400, Stephen J. Rush wrote:

On Wed, 23 May 2007 16:58:20 -0400, Tom Del Rosso wrote:

"ian field" wrote in message


Any vintage, and especially wartime electronics (allied *or* axis) is
of interest, if you have any such schematics I would be pleased to
see them.

I'd like to soo an allied encryption machine from that time. The enigma is
so well known, and ours must be declassified since new techniques were out a
few years after the war, yet it isn't described anywhere.

You haven't Googled it? I recently StumbledUpon a site offering an
electronic version of Enigma. The original Enigma is out there too; it
was patented before the war, so its design was never secret (the secrets
were the wiring and starting positions of the rotors and the settings of
the plugboard).

I would really like to see a detailed description of the cryptanalysis of
the "Purple" cypher that was Japan's answer to Enigma. The American
cryptographers who broke that one built their own logically-equivalent
machine without ever seeing a Purple machine. Then there was the Allied
SIGABA, which, as far as anyone is willing to admit, was never broken. It
used rotors to control the motion of other rotors.

http://www.imdb.com/title/tt0057076/

Cheers!
Rich

On Wed, 23 May 2007 16:54:17 -0400, "Tom Del Rosso"
wrote:

"John Larkin" wrote in
message

Oh, if any fool tells you that these were not Doppler detectors, well,
ignore them.

Jim says the door sensors at the supermarket are doppler too, and they work
even when people are not shot at the door from a canon.

It's even amazing that the shells work that way, since they move at a pretty
small fraction of c.

The mixer output frequency is 2 times the number of wavelengths per
second that the distance changes. For a wavelength around one meter,
with a shell going 300 m/s, that's about 600 Hz. That audio tone fires
the thyratron and boom.

The Brits had been firing an average of roughly 2000 ack-ack shells to
bring down a German bomber. Once they got the prox fuze, the number
dropped to something like 200. Proximity artillery and mortar shells
propelled Patton across Europe as fast as his logistics could keep up.


The time-frames defy logic too. Radar is invented, then it took a couple of
years for miniaturized doppler radar, then another 25 years for doppler
radar on the F14.

Some WWII radar altimeters were sort of doppler, too. They transmitted
a cw signal that was frequency modulated by a sawtooth. They mixed the
ground echo with the transmit signal and the resulting audio frequency
was proportional to altitude.

John

On Wed, 23 May 2007 18:13:37 -0400, Tom Del Rosso wrote:

"Stephen J. Rush" wrote in message
news

You haven't Googled it? [.....]

[....]. Then there was the Allied SIGABA, which, as far as anyone
is willing to admit, was never broken. It used rotors to control the
motion of other rotors.

I've googled, but SIGABA never came up. Thanks.

I found SIGABA at wikipedia, but of Purple, I can find only the fact that
it was broken before December 1941, so the message instructing the embassy
in Washington to break off negotiations was intercepted. That was an
ominous sign, but no Purple message ever mentioned the Pearl Harbor
strike, because the Japanese military planners didn't trust the Foreign
Office.

I can't find any hint of how the American cryptanalysts were able to break
Purple and the more important Japanese naval code with only cyphertext to
work with. Remember, Bletchley Park had Enigma machines.

"Stephen J. Rush" wrote in message
news

I can't find any hint of how the American cryptanalysts were able to
break Purple and the more important Japanese naval code with only
cyphertext to work with. Remember, Bletchley Park had Enigma machines.

Some of those articles say that the key was learning that it used phone
stepping switches. That must have given away the modulus number or
something like that. The switches also were not removeable like enigma
rotors.


--

Reply in group, but if emailing add another
zero, and remove the last word.

"Rich Grise" wrote in message
news
On Wed, 23 May 2007 17:16:51 -0400, Tom Del Rosso wrote:

"ian field" wrote in message


The Bletchley Park Trust has reconstructed the Colossus
semi-programmable computer as used to crack Enigma codes.

Yeah, but it's always their codes and our code-breaking. I'm sure we
didn't
transmit in the clear.

Of course not. We translated it to Navaho.

Cheers!
Rich



There was a movie about that - was it the Windtalkers?

"Stephen J. Rush" wrote in message
news
On Wed, 23 May 2007 18:13:37 -0400, Tom Del Rosso wrote:

"Stephen J. Rush" wrote in message
news

You haven't Googled it? [.....]

[....]. Then there was the Allied SIGABA, which, as far as anyone
is willing to admit, was never broken. It used rotors to control the
motion of other rotors.

I've googled, but SIGABA never came up. Thanks.

I found SIGABA at wikipedia, but of Purple, I can find only the fact that
it was broken before December 1941, so the message instructing the embassy
in Washington to break off negotiations was intercepted. That was an
ominous sign, but no Purple message ever mentioned the Pearl Harbor
strike, because the Japanese military planners didn't trust the Foreign
Office.

I can't find any hint of how the American cryptanalysts were able to break
Purple and the more important Japanese naval code with only cyphertext to
work with. Remember, Bletchley Park had Enigma machines.



The Enigma machine was quite commonplace before the war, it was originally
marketed to prevent industrial espionage.

AFAIK the first Enigma was supplied to British intelligence by Polish
mathematicians who were already working on ways to crack the encryption.

The Germans may have supplied Enigma to the Japanese, but that was something
I saw in a war movie and may be fiction!

On Wed, 23 May 2007 18:01:17 -0400, Chuck Harris
wrote:

Tom Del Rosso wrote:
"ian field" wrote in message

The Bletchley Park Trust has reconstructed the Colossus
semi-programmable computer as used to crack Enigma codes.

Yeah, but it's always their codes and our code-breaking. I'm sure we didn't
transmit in the clear.

Well, we sure did with airplanes. Perhaps it wasn't an automated
process during WWII? Single use pads were and are still popular.

The breakthrough was UHF voice comm (called TBS when used between Navy
ships.) It had limited range and the enemey generally didn't have the
technology to intercept.

John

"Phil Allison" wrote in message
...

"john jardine"

http://www.tubedata.org/unknown_sylv..._sylvania.html


I read those patents at the bottom of the page and am still none the
wiser
about the detection method. The patents say phasing in/out reflections
from
the aircraft, modulate the oscillator anode current at an audio
frequency
and trigger the detonator. (ie a Doppler effect but not mentioned as
such).


** That the modulation frequency is stated to drop as the shell approaches
a
target is a dead give away for Doppler being involved. As a shell passes
nearby a target, the relative speed and hence Doppler frequency shift
drops
to near zero.


Would have thought current variations due to that cause would be
immeasurable.


** Then you did not do much thinking.

I spent ages. About a minute!.

1. The wavelength of the radiated energy ( circa 200MHz) is many times
smaller than the wingspan of a fighter or bomber aircraft.

Yes. I assumed an infinite metal sheet.

2. The proximity for detonating the shell with effect is roughly
comparable
with the wingspan of such aircraft.

I didn't know that. I was using something like one wavelength at 100MHz
but on reflection this is too close to be of practical use.

3. Egro - an ( all metal) aircraft will be a significant reflector of
such
radiated energy when it is within range of being damaged.

It appears from the circuit arrangement that RF modulation of less than 1%
at around 100Hz would be more than enough to cause detonation.

Yes. This is the key point I missed. Oscillator 'RF modulation' as the
working mode. The oscillator tuned circuit Q being altered at an audio
rate by variable aerial loading dependant on resonant frequency,
velocity and strength of reflection. A 3.7" AA shell seems about a 250Hz
shift, which fits nicely in the audio bandpass.


No mention in the patents though of any audio effects due to
the shell spinning at 300Hz,


** There is unlikely to be any - AA shells being nicely symmetrical.

Yes, indeed. Looking at the pics I see the full cone radiator element acting
with the symmetrical shell body. I'd read the drawing as an arrow head
shaped dipole.


...... Phil



It's interesting historical stuff this. I'll look for that "The Deadly Fuze"
book.




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"Fred Abse" wrote in message
newsan.2007.05.27.16.51.20.825090@cerebrumconfus .it...
On Sat, 26 May 2007 01:44:21 +0100, john jardine wrote:

I read those patents at the bottom of the page

Did you notice that one of the grantees (??) of 3113225 was James A. Van
Allen?

Yes. Ians third link had a nice personal biog' at ...
http://www.jhuapl.edu/techdigest/td1802/vanallen.pdf



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On Sun, 27 May 2007 02:53:05 +0100, "john jardine"
wrote:


"Phil Allison" wrote in message
...

"john jardine"

http://www.tubedata.org/unknown_sylv..._sylvania.html


I read those patents at the bottom of the page and am still none the
wiser
about the detection method. The patents say phasing in/out reflections
from
the aircraft, modulate the oscillator anode current at an audio
frequency
and trigger the detonator. (ie a Doppler effect but not mentioned as
such).


** That the modulation frequency is stated to drop as the shell approaches
a
target is a dead give away for Doppler being involved. As a shell passes
nearby a target, the relative speed and hence Doppler frequency shift
drops
to near zero.


Would have thought current variations due to that cause would be
immeasurable.


** Then you did not do much thinking.

I spent ages. About a minute!.

1. The wavelength of the radiated energy ( circa 200MHz) is many times
smaller than the wingspan of a fighter or bomber aircraft.

Yes. I assumed an infinite metal sheet.

2. The proximity for detonating the shell with effect is roughly
comparable
with the wingspan of such aircraft.

I didn't know that. I was using something like one wavelength at 100MHz
but on reflection this is too close to be of practical use.

3. Egro - an ( all metal) aircraft will be a significant reflector of
such
radiated energy when it is within range of being damaged.

It appears from the circuit arrangement that RF modulation of less than 1%
at around 100Hz would be more than enough to cause detonation.

Yes. This is the key point I missed. Oscillator 'RF modulation' as the
working mode. The oscillator tuned circuit Q being altered at an audio
rate by variable aerial loading dependant on resonant frequency,
velocity and strength of reflection. A 3.7" AA shell seems about a 250Hz
shift, which fits nicely in the audio bandpass.


No. The oscillator runs at constant frequency and amplitude. Weak RF
reflections from the target are mixed with the transmit signal. Since
the echoes are a different frequency from the transmitted signal, a
doppler beat frequency results; it can be amplified and used to fire
the thyratron. The WWII vintage fuzes, like the ones I posted, didn't
look for a change in the doppler frequency, just its presence. By the
time they detected any echo, it was time to fire the squib.

A plane, or even the surface of the earth or water (in the case of
artillery) 30 feet away wouldn't usably affect the Q of the tuned
circuit.

John

"John Larkin" wrote in message
...
On Sun, 27 May 2007 02:53:05 +0100, "john jardine"
wrote:


"Phil Allison" wrote in message
...

"john jardine"

http://www.tubedata.org/unknown_sylv..._sylvania.html


I read those patents at the bottom of the page and am still none the
wiser
about the detection method. The patents say phasing in/out
reflections
from
the aircraft, modulate the oscillator anode current at an audio
frequency
and trigger the detonator. (ie a Doppler effect but not mentioned as
such).


** That the modulation frequency is stated to drop as the shell
approaches
a
target is a dead give away for Doppler being involved. As a shell
passes
nearby a target, the relative speed and hence Doppler frequency shift
drops
to near zero.


Would have thought current variations due to that cause would be
immeasurable.


** Then you did not do much thinking.

I spent ages. About a minute!.

1. The wavelength of the radiated energy ( circa 200MHz) is many times
smaller than the wingspan of a fighter or bomber aircraft.

Yes. I assumed an infinite metal sheet.

2. The proximity for detonating the shell with effect is roughly
comparable
with the wingspan of such aircraft.

I didn't know that. I was using something like one wavelength at 100MHz
but on reflection this is too close to be of practical use.

3. Egro - an ( all metal) aircraft will be a significant reflector of
such
radiated energy when it is within range of being damaged.

It appears from the circuit arrangement that RF modulation of less than
1%
at around 100Hz would be more than enough to cause detonation.

Yes. This is the key point I missed. Oscillator 'RF modulation' as the
working mode. The oscillator tuned circuit Q being altered at an audio
rate by variable aerial loading dependant on resonant frequency,
velocity and strength of reflection. A 3.7" AA shell seems about a 250Hz
shift, which fits nicely in the audio bandpass.


No. The oscillator runs at constant frequency and amplitude. Weak RF
reflections from the target are mixed with the transmit signal. Since
the echoes are a different frequency from the transmitted signal, a
doppler beat frequency results; it can be amplified and used to fire
the thyratron. The WWII vintage fuzes, like the ones I posted, didn't
look for a change in the doppler frequency, just its presence. By the
time they detected any echo, it was time to fire the squib.

A plane, or even the surface of the earth or water (in the case of
artillery) 30 feet away wouldn't usably affect the Q of the tuned
circuit.

John


But where's the non linearity for the mixing action?.
Way I was reading it is that the reflected energy is increasing/decreasing
the radiation resistance of the aerial as the rxed reflections phase in and
out, dependant on distance from target.
Sort of like an output load resistor is being twiddled by the rxed chirp.
Hence the tuned circuit (inclusive of aerial) dynamic resistance [Q] must
also vary in a cyclic manner.
Therefore, for constant oscillations to be maintained, (oscillator prime
directive the anode current must modulate in sympathy with the prevailing
phase and strength of reflections.
So yes, constant frequency (a little pulling close on target) and R.F.
output voltage but variable L.F. anode current, as the level-control servo
loop struggles to force a constant oscillator output.
No?.



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