Frequency Sleuthing Methods Re: [MilCom] VHF/UHF Military Spectrum

[Tom Greenwood]

Jack

I have used the method below in my attempt to sleuth new freuencies.  The
real key to it is dedication and patience.  When you have completed, you
start the whole process all over again.  Now that I am an adult and not so
close to home during the day, the method has to be tweeked slightly but it
is basically the same.  A few things to note are that the results may vary
from day to day, may not be repeatable every day, and short of having
yourself an NSA grade monitoring station, you most likely will not gather
everything that is going on.  As I said above, the key to it is patience and
dedication.

1	Break up the spectrum that you are interested in sleuthing into manageable
slices of spectrum that you can quickly and repeatedly scan.  I like to use
a scanner that has an auto write feature, that is, it writes new frequencies
as they are found to memory channels.  For years I have used an R7000 with
excellent results.  Ancient by today's standards but it has been a proven
piece of equipment and a workhorse for me for many years.

2	As a rule of thumb, I like to keep the entire sweep time, that is the time
to fully scan the limits of the spectrum slice to under 15 seconds.  Keep in
mind that most transmissions are under 5 seconds.  You want to maximimize
your likelihood of landing on the communication during the brief time that
it may be active.

3	Try to match the scan increments to that commonly used in the band that
you are sleuthing.  For the UHF milair band, use 25 KHz steps.  Even 20
years ago as I went through this exercise, it was still quite effective
although then, 100 KHz steps would probably have been adequate for most
scans in the milair band.  What you want to try to do, is to maximize the
number of discrete frequencies that you can hit.  In the government LMR
bands, 12.5 KHz is probably what you want to use today.

4	Keep a database of everything that you hear.  Use excell, access, or any
other manageable software that will allow you to quickly sort and search
your results.  This is going to help you tremendously in focusing your
efforts on the things that you don't know.

5	Use recording software or a VOX operated switch to a tape recorder to
record your scans.  If available such as on the R7000, activate the speech
synthesizer to identify the frequency when the scanner lands on a
communication.

6	Now comes the trick to quickly accumulating a mass of information, much of
it identifiable.  Run the scan and leave it alone for many hours.  When I
was a student, I would run it from about midnight until noon without
touching it.  At about noon, I would review and record all of the
frequencies that I caught entering the new frequencies into the database.
Any that I could not identify or that were new, I would place into a bank in
the scanner and start the scanning process over only scanning the
unidentifiable frequencies.  During that time, I leave the speech
systhesizer active and the recorder going.  I leave this running for the
next 12 hours.  I can then review it later to see if I can gather more
information from the comms in an attempt to identify who is using the
channels.  Again, record your results in a database or equivalent.

7	The next day, you repeat the whole process scanning a new slice of
spectrum.  If you cannot make the first review after 12 hours, try 24 hours.
Do the spectrum slice scan on the first day and then do the discrete
frequency scan on the following day.  Generally, I could search the entire
UHF milair band in about 35 days.  When I had completed searching the entire
band, I started the whole process all over again.

I hope this helps you.  Best of luck and happy sleuthing.

Tom Greenwood, N1JQB
Metro West Boston