[FedCom] Direction Finding Techniques for Fedcom Freqs?

[KD7JYK]

I have a bow-tie type direction finding antenna as well, never used it.
They were popular as kits in the early 90's, I bought it assembled and used
from a fellow at the TRW swapmeet.

I had the opportunity to track down an HF digital signal a few months
back...  I had heard the signal on HF, the band was completely dead except
for this signal so I figured the origin was 10 - 15 miles.  I had a good
signal with my dipole E-W, nothing N-S so I figured the source was between
Carson City, Nevada and Fallon, NV.  I put a 24" whip on the roof of my
4Runner, an attenuator good to 101dB, plus the 20 or 30 dB (I forget
exactly) attenautor in my IC-706MKII and off I went.  Something told me to
head to Fallon despite it being nearly 50 miles.  Pre-amp on, attenuators
out, nothing...  I stop for gas and I can faintly hear the signal, I know I
am getting close.  Turns out I was about two miles from the source, but with
the tiny antenna and probably different polarization, I couldn't hear it too
well.  I drive farther east...  Finally it is full scale.  I turn off the
pre-amp.  Signal strength drops a little.  I switch in the attenuator, it
drops more.  I start driving a grid, switching more and more attenuation in,
by the time I was through, I had switched in about 117dB and was driving
around one block, even being on the other side of the street made a
difference in whether I could hear it or not.  What's on the block?  A fire
department, and old court building the town jail and the telephone company.
The phone comany has one visible microwave dish.  The fire department has
nothing appearing to be HF, there are no antennas visible on the court
building which I think is now a museum, that leaves the cluster of antennas
on the jail.  I didn't see anything obvious, though there could have been a
longwire or dipole, it was late at night and hard to see exactly what was
strewn about.  I have yet to go back to look for the HF antenna, I still
hear the signal from time to time, it repeats every eight seconds.  I have a
recording for those interested.

Kurt