As we have seen, the messages sent in the daily skeds consist of cipher groups and some plaintext messages of fictitious incidents. The traffic simulates different radio nets, but is all sent by one transmitter. Various modes are sent and are changed often. It is obviously a training operation of some sort. And, judging from the traffic sent, it's obvious that it is being used to train US military radio intercept operators.
Therefore, I believe the receiving site is located at Fort Huachuca in Arizona.
Fort Huachuca is home to the US Army Intelligence Center and School, where operators from all four branches of the military are trained in SIGINT collection. The Army used to train CW collection at Fort Devens, MA, where I trained, but moved it to Ft. Huachuca when Ft. Devens was slated for closure. Another interesting fact is that before I left the military in 1993, the jobs of Morse Systems Operator (CW collection) and Printer Systems Operator (RTTY collection) were being combined into one job. It only makes sense that these operators should be trained in both CW and RTTY collection, which coincidentally is what the daily transmissions of this station consist of.
It is interesting to note that when I was being trained in CW collection at Ft. Devens back in 1990, we trained on receiver simulators instead of actual on-air signals. The receivers were simulated Racal RA/6790GM receivers that used computer-generated "radio" signals. We could tune around the bands with absolutely no atmospheric noise (what a blessing!) and copy whatever targets the computer told us to copy. The instructors could add simulated interference to the audio so we could practice copying through tough noise and/or jamming. I believe this system is probably still in use, unless they upgraded to something better. What I'm not sure of is why they are using real signals on the air for their training, when they have the simulators to work with. However, live, on-air signals would give the trainees better experience of propagation and atmospheric conditions.
Another interesting thing to note is the times of the broadcasts. Each sked is at 1500 and 1900 UTC, which corresponds to 0800 and 1200 Arizona time. The transmissions usually last for about three hours, so this gives two hours of copy from 0800 to 1100, and two hours from 1200 to 1500 Arizona time. Arizona does not observe Daylight Savings Time, so the skeds are one hour later during the summer months. The break from 1100 to 1200 would coincide with a lunch break. The afternoon sked is normally the same as the morning sked, so it's apparent that two classes are trained every day, one in the morning and one in the afternoon. This is similar to the way the school was run when I went through it. One last interesting item: This station is never on the air on national holidays, which would be in keeping with policies for most military schools.
And where would the transmitter be located? That is a tough one. Obviously, the military would want it located where it would be able to take advantage of excellent propagation into Arizona on 10225 and 16303.6 kHz. I'm not an expert in propagation, so I can't begin to guess where this would be. The signal is usually weak to good here at my central US location. If anyone has an idea or any knowledge as to the transmitter location, I'd like to hear from you.
Over the past couple of years, I have accumulated a large amount of intercept of this station and have it all stored in one text file. If anyone is interested in receiving a copy, e-mail me at the address at the top of the page and I'll send it to you. It makes for some interesting traffic analysis, even though all the traffic is simulated. As I have said, this station has made for some of the most interesting monitoring I've come across. And I plan to keep monitoring this one in the future.
