The Foxtrot (Noah’s Ark) message was a form of Emergency Action Message (EAM) that was (and still is) transmitted periodically and whose purpose was considered classified. The message was sent to the DEWLine stations periodically from the Data Centers at the Main Stations and then relayed to aircraft in a blind radio transmission. While in console operator training at Streator Ill in the 1970’s,  trainees were told that the transmissions were to be made on 236.6 MHz. In actual practice, in the 1960’s on the DEWLine, transmissions were made on the UHF emergency frequency of 243.0 MHz. This may have changed to 236.6 MHz in later years.

Although classified, the Foxtrot message was widely known as being part of the Strategic Air Command’s (SAC) positive control program for sending the Go-No Go message throughout their system. While its purpose has changed over the intervening years you can still here the “Skyking, Skyking” transmissions on specified HF frequencies (see below) of the USAF’s HF-GCS (High Frequency – Global Communication System).

 

Foxtrot Message Format
The content of the Foxtrot message, and indeed its name, have changed over the years. In the 1960’s, it was called the Noah’s Ark message and the content was usually two words and a letter, spoken phonetically. In the picture below, taken in the early 60’s, you’ll notice that the message was “Silver Cup Charlie.” It seems that in the 70’s, the message content changed to a 3-4 letter format.

 

Foxtrot Message Handling Procedures.
When a new Foxtrot message was received at the Main Station Data Center, the Data Control Officer would open the circuits to the stations under his control and pass the following verbal traffic to the Console Operators:

“Foxtrot, Foxtrot, Foxtrot”
“Skybird, break, break: __, __, __, __.“ (The Foxtrot message, a 3-4 letter sequence.)
“Break, break: time, ##.” (Minutes past the current hour).
“Authentication : __, __,.” (A two letter authentication code tied to the time).
“I say again.” (The message is repeated).
“Over.”

 

At this point the console operators receiving the Foxtrot message go to the KTA 2000A booklet (in the 1960’s it was the KAA-29 one-time pad of voice authorization codes) on the console and open it to the proper day of the month and to the proper minutes after the hour and cross check the two letters next to the time to see if they correlate with the authentication letters provided by the Data Control Officer. If they correlate the console operator responds with:

“I accept your Foxtrot message at ## (time after the hour). My initials are __ __. (Station) out.”

Then the console operator proceeds to make a blind transmission using the following format:

“Skyking, Skyking.”
“This is Staghound Radio, Staghound Radio.” (The station’s tactical call sign. You can see a list of tactical call signs here.)
“Do not answer, do not answer.” (The reason for the ‘do not answer’ is so that aircraft would not give away their position.)
“Break, break.”
“ __, __, __, __.” (The Foxtrot message.)
“Break, break.”
“Time ## .“ (Minutes after the hour.)
“Authentication: __, __.” (New, two letter authentication code per current, new, time.)
“I say again.” (Repeat the entire message.)
“Staghound out.”

 

Next the console operator contacts the adjacent station down the Line, moving west to east in the same sector, telling them to proceed with their Foxtrot message. Finally, the Foxtrot message is entered into the console log with the Data Center code underlined. (Note: Paul Kelley recalls that rather than that transfer happening within each sector, it started on the western part of the DEWLine and progressed sector by sector which would mean that no two stations would be transmitting the message at the same time. It may be a matter of training versus actual.)

The only other time that a station would transmit the Foxtrot message was when requested for “traffic” by a military aircraft. After receiving a request for traffic the protocol was to say nothing but prepare the proper authentication and transmit the Foxtrot message. Here is a typical request.

 

 

Military B-52: “Staghound Radio, this is Boxer 24 on 236.6. Do you copy?”
Fox Main: “Boxer 24, Staghound Radio. Copy you five by five. Over.”
Military B-52: “Staghound, Boxer 24. Do you have any traffic for me? Over.”
Fox Main: At this point the console operator does not reply but looks up the proper authentication code for the current time and transmits the Foxtrot message in the format noted above.

 

Skyking Today
Anyone with a good shortwave radio and some patience can still hear the “Skyking” message to this day. The more common radio frequencies are 11.175 MHz, 6.712 kHz, 8.992 kHz, 13.200 MHz, and 15.016 MHz, among others. Broadcasts are usually upper sideband (USB).

Hearing those broadcasts still sends a shiver down my spine knowing what I know about their nature and purpose.