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

Irv


--
--------------------------------------
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

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.

See URL:
http://www.qmfound.com/lady_be_good_...r_recovery.htm

----------------------------------

On our Navy planes in the 50's we had two ARN-6 - ADF (Direction Finders),
100-1750 KHz
In conjunction with Loran -- we usually knew where we were. (;-)

But also the Navigator would take periodic sextant readings (weather
permitting) thru a bubble on top of the aircraft

No GPS in those days.(;-(

On one of the squadrons flights -- a circuit breaker blew and refused to be
reset -- avionics were off -- the crew flew dead reckoning most of the rest
of the flight.


--
Caveat Lector (Reader Beware)
Help The New Hams
Someone Helped You
Or did You Forget That ?



"Irv Finkleman" wrote in message
...
"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). The HFDF used loops
feeding
a mechanically rotating gonio with output to a crt.

Irv


--
--------------------------------------
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

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

Caveat Lector wrote:
"A WWII B-24 bomber (Lady Be Good) ran out of fuel because they were not
sure of the DF readings."

Too bad they ran out of gas and drash landed in the Libyan desert. The
B-24 must have been covered with sand for most of the time because there
was still most of it intact to be found.

On April 4, 1943, the Lady Be Good radioed for a directional reading
from the high frequency direction finding station at Bernina as the
earth was covered with clouds and there were strong winds causing
navigational errors. They needed a position fix.

I had breakfast this morning with a WW-2 B-24 pilot who flew in the same
area. He said that requests for position fixes were often answered by
Germans pretending to be the direction finding facility, and they would
intentionally lead the questioners astray.

Best regards, Richard Harrison, KB5WZI

"Richard Harrison" wrote in message
...
Caveat Lector wrote:
"A WWII B-24 bomber (Lady Be Good) ran out of fuel because they were not
sure of the DF readings."

Too bad they ran out of gas and drash landed in the Libyan desert. The
B-24 must have been covered with sand for most of the time because there
was still most of it intact to be found.

On April 4, 1943, the Lady Be Good radioed for a directional reading
from the high frequency direction finding station at Bernina as the
earth was covered with clouds and there were strong winds causing
navigational errors. They needed a position fix.

I had breakfast this morning with a WW-2 B-24 pilot who flew in the same
area. He said that requests for position fixes were often answered by
Germans pretending to be the direction finding facility, and they would
intentionally lead the questioners astray.

Best regards, Richard Harrison, KB5WZI

Interesting -- code operators could tell one operator from another just by
their style or fist.
Wonder if CW was used for the request and reply ???

--
Caveat Lector (Reader Beware)
Help The New Hams
Someone Helped You
Or did You Forget That ?

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