In message , Irv Finkleman
writes
"M. J. Powell" wrote:

In message , Irv Finkleman
writes
RB wrote:

Brings back scenes from old WWII movies....

Small loops are still used and seem to be very effective for DF. I
think that
the ARRL antenna book provides information in this direction. One system I
saw used a short ferrite dipole array.

In most cases, DF sets displayed their goniometer outputs on a CRT or as
signal strength on a meter. In this case, the dots and dashes melded into
a continous output because of the persistence of the CRT or the AGC delay
of the receiver.

I don't think there was a swinging goniometer with the CRT DF set. The
output of the two loop aerials fed the X and Y plates respectively so
that the trace appeared at the right angle and the bearing was read from
the screen.

Mike

There were a number of different types of DF sets. Some, as you
point out had x and y
plates connected to the loops, another had a mechanically rotating gonio.
We had one for radar detection which used horns with crystal detectors in
it which went to x and y plates (through amps).

That's interesting. I didn't know of microwave DFing.

The HFDF used loops feeding
a mechanically rotating gonio with output to a crt.

Ah! Right. Now I've got it. Thanks.

Mike

Interestingly, aircraft used small loop type antennas for MF/HF DF in the
40s and 50s. Just turn loop for a null, and (maybe) use an omni sense
antenna. Two spaced reception stations give a reasonable fix for a ground
system.

JE

"John Edwards" wrote in message
...
Some years ago, the local gov department (fcc to you) here in aus carried
out test on their hf df. They were able to pinpoint a station in soth
australia within about 1 km or so. Impressive I thought at the time.

JE

"Buck" wrote in message
...
In WWII the allies were able to pinpoint the locations of German HF
transmissions very accurately. They were able to pinpoint the
locations of U-boats, etc. when they transmitted. (or so I have been
led to believe).

What methods did they use to do this? Is it something duplicatable
with Radio Amateurs in general or does it require some special type
equipment?


I hear lots of amateurs describing interference and other problems on
HF, but no one seems to be triangulating the offending stations. I am
guessing that the real secret was in their communications with the
'spotters' to triangulate the positions.

Any suggestions?

Thanks

--
73 for now
Buck
N4PGW

I hear lots of amateurs describing interference and other problems on
HF, but no one seems to be triangulating the offending stations. I am
guessing that the real secret was in their communications with the
'spotters' to triangulate the positions.

Adcock arrays http://www.airwaysmuseum.com/HF%20CR%20DF%201.htm
http://members.aol.com/BmgEngInc/Adcock.html
worked quite well, but they require precision in construction, as well as
the site.
For VHF/UHF, there are all sorts of things available :)
N0MKJ and I used to hunt with the "fox-copter", featured in the 3/94 73
magazine.

Here's some references in 73 magazine:
http://www.pejla.se/ardf_litteratur.htm

And a bunch of links to play with:
http://www.dxzone.com/catalog/Operat...ction_Finding/

Wullenweber: German for wool weaver. Germans had several in WW2, none existed elsewhere. Sites were stripped and
burned and the big iron goniometers buried during the closing days of the war. Took quite a bit of effort by ONR and
OSS to retrieve enough material to reconstruct the concept. And a lot of work at U of Ill. and ITT/FTR to make one
work. Beamformers, not TOA. That came a lot later.

The initial question was set in the WW2 time period, I believe.

Crazy George
the ATTGlobal.net extension is a SPAM trap. Use att dot biz instead.

One night in 1944, there were a thousand Lancaster killing machines and
other RAF bombers over Germany, complete with aircrews who well knew what
they were about. It was a moonless and cloud-overcast night over the whole
of Western Europe. Targets were civilian firestorm-raids on German towns and
cities.

Navigation was via GEE equipment, a British hyperbolic, pulse-radar, VHF,
1942 invention which later, as the LF and VLF versions, was given the
American name of LORAN (who copied it in the same size boxes.)

With GEE it was possible to accurately navigate several hundred miles from
base and return safely even with fog over the airfield. Aircrews had become
to depend on it and had neglected, forgotten how to use, other means of
navigation such as dead-reckoning and the magnetic compass.

From shot-down and crashed aircraft the Germans had discovered the
frequencies used by GEE receivers and fathomed-out how the equipment worked.
But instead of using jammers immediately as they came out of the factories
they waited until there was an appreciable quantity of them, waited until
navigation conditions were difficult, no moon or stars, dispersed the
jammers around Europe, waited until there were a 1000 bombers in the air,
and then switched them all on simultaneously.

German radar-controlled anti-aircraft guns were always accurate. They were
used in clear skies in daylight, sometimes in preference to optical
instruments and range finders. Hundreds of bombers, lost, wandering about
Europe were better than usual targets.

More than 100 heavy bombers failed to return to base. Some crash-landed,
running out of fuel in Sweden, Poland, central Europe, northern Italy,
France, even in north Africa. Others came down in the north sea. It was the
geatest disaster in one night ever incurred by the RAF.

Although heavy losses and damage to aircraft was a normal event, the loss of
more than 100 trained aircrews was a catastrophy. Incidentally, during the
whole war 40,000 aircrew lives were lost due to enemy action and another
30,000 were lost due to flying accidents of one sort and another.

But, as usual, Uncle Sam helped us out. GI's left behind 70,000 unmarried
mothers in the UK.

I just love statistics! ;o)
----
Reg.

Caveat Lector wrote:

All about DF, sense antennas, nulls, etc
http://www.avweb.com/news/avionics/183233-1.html

Side note -- A WWII B-24 bomber (Lady Be Good) ran out of fuel because they
were not sure of the DF readings --that is -- if they were going toward or
away from the home station. Crashed in the Libyan desert -- all of the crew
perished after walking as far as 85 miles in the desert.

On DF antennas sense was always something to be taken with a grain of salt.
It was quite easy to have a reading 180 degrees out. We always had to consider
other factors about the targets such as where the coast was, or where the
last reported position of the target was.

I spent most of my time in the navy as an operator, then supervisor technician ('57 -
'83) with shipborne electronic warfare. After commissioning I was Operations Officer at
two Canadian stations who were part of the USN based Bullseye HFDF system (Wullenweber
Antennae), and then as Operations Officer at CFS Alert, a small sigint/comint station at
the northern tip of Ellesmere Island (300 miles north of Thule). Brrrr.

I went from pre-WW2 DF equipment (Canadian Navy was always a little slow in updating),
to the latest state of the art -- or at least it was in 1983 when I left. It was
a most interesting career. It still is, for the guys who are still in it.

You might find some good information and links on my Oldtimers Website listed
below.

Irv VE6BP

--
--------------------------------------
Diagnosed Type II Diabetes March 5 2001
Beating it with diet and exercise!
297/215/210 (to be revised lower)
58"/43"(!)/44" (already lower too!)
--------------------------------------
Visit my HomePage at http://members.shaw.ca/finkirv/index.html
Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm
Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm
--------------------
Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada

And your problem is?
Being of German descent with relatives in Germany, I feel that the
German people got what they deserved. Actions by the Luftwaffe were just
as horrific in London, Warsaw, Stalingrad and Antwerp to name a few.
The Luftwafe had similar devices to locate their targets in England with
the same results when their systems were captured by British Military
Intelligence (what an oxymoron).
BTW the Lancaster was one of the finest aircraft of it's type ever.

Dave WD9BDZ


Reg Edwards wrote:

One night in 1944, there were a thousand Lancaster killing machines and
other RAF bombers over Germany, complete with aircrews who well knew what
they were about. It was a moonless and cloud-overcast night over the whole
of Western Europe. Targets were civilian firestorm-raids on German towns and
cities.

Navigation was via GEE equipment, a British hyperbolic, pulse-radar, VHF,
1942 invention which later, as the LF and VLF versions, was given the
American name of LORAN (who copied it in the same size boxes.)

With GEE it was possible to accurately navigate several hundred miles from
base and return safely even with fog over the airfield. Aircrews had become
to depend on it and had neglected, forgotten how to use, other means of
navigation such as dead-reckoning and the magnetic compass.

From shot-down and crashed aircraft the Germans had discovered the
frequencies used by GEE receivers and fathomed-out how the equipment worked.
But instead of using jammers immediately as they came out of the factories
they waited until there was an appreciable quantity of them, waited until
navigation conditions were difficult, no moon or stars, dispersed the
jammers around Europe, waited until there were a 1000 bombers in the air,
and then switched them all on simultaneously.

German radar-controlled anti-aircraft guns were always accurate. They were
used in clear skies in daylight, sometimes in preference to optical
instruments and range finders. Hundreds of bombers, lost, wandering about
Europe were better than usual targets.

More than 100 heavy bombers failed to return to base. Some crash-landed,
running out of fuel in Sweden, Poland, central Europe, northern Italy,
France, even in north Africa. Others came down in the north sea. It was the
geatest disaster in one night ever incurred by the RAF.

Although heavy losses and damage to aircraft was a normal event, the loss of
more than 100 trained aircrews was a catastrophy. Incidentally, during the
whole war 40,000 aircrew lives were lost due to enemy action and another
30,000 were lost due to flying accidents of one sort and another.

But, as usual, Uncle Sam helped us out. GI's left behind 70,000 unmarried
mothers in the UK.

I just love statistics! ;o)
----
Reg.

On Fri, 18 Feb 2005 18:55:07 -0500, "Dave VanHorn"
wrote:


I hear lots of amateurs describing interference and other problems on
HF, but no one seems to be triangulating the offending stations. I am
guessing that the real secret was in their communications with the
'spotters' to triangulate the positions.

Adcock arrays http://www.airwaysmuseum.com/HF%20CR%20DF%201.htm
http://members.aol.com/BmgEngInc/Adcock.html
worked quite well, but they require precision in construction, as well as
the site.
For VHF/UHF, there are all sorts of things available :)
N0MKJ and I used to hunt with the "fox-copter", featured in the 3/94 73
magazine.

Here's some references in 73 magazine:
http://www.pejla.se/ardf_litteratur.htm

And a bunch of links to play with:
http://www.dxzone.com/catalog/Operat...ction_Finding/

Thank you,

I bookmarked the DF antenna and am reading the other articles.



--
73 for now
Buck
N4PGW

In message , David G. Nagel
writes
And your problem is?
Being of German descent with relatives in Germany, I feel that the
German people got what they deserved. Actions by the Luftwaffe were
just as horrific in London, Warsaw, Stalingrad and Antwerp to name a few.
The Luftwafe had similar devices to locate their targets in England
with the same results when their systems were captured by British
Military Intelligence (what an oxymoron).

Do you consider Prof. R.V. Jones to be an oxymoron? Or any other kind of
moron?

Mike

M. J. Powell wrote:
In message , David G. Nagel
writes

And your problem is?
Being of German descent with relatives in Germany, I feel that the
German people got what they deserved. Actions by the Luftwaffe were
just as horrific in London, Warsaw, Stalingrad and Antwerp to name a few.
The Luftwafe had similar devices to locate their targets in England
with the same results when their systems were captured by British
Military Intelligence (what an oxymoron).


Do you consider Prof. R.V. Jones to be an oxymoron? Or any other kind of
moron?

Mike

Individuals are always the exception...

Dave