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.


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"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


--
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--------------------
Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada