This is the first of two columns that will discuss probably the most widely-heard numbers stations in North America, the Cuban CW cut number stations and the YL/SS "Atencion" & "Finale" stations. These stations are run by Cuban intelligence and are believed to be transmitted from the large communications facility at Bauta, Cuba. This is also home to Russia's largest overseas SIGINT (Signals Intelligence) facility. It is without a doubt that the CW and voice stations are related. I have heard a CW station mixing with a YL/SS voice broadcast on at least one occasion, and many frequencies are used by both the CW and voice stations. What may not be realized by some is that most voice numbers stations have a CW counterpart.

First, we'll take a look at the CW stations. These stations use what are called cut numbers, or letters substituted for each number. Cut numbers are used by various agencies around the world so that the whole number doesn't have to be sent in Morse code. This cuts down the time the transmitter has to stay on the air and makes it easier for the recipient to copy. There are many different types of cut number substitutions in use, but the Cuban stations use the following: 1=A, 2=N, 3=D, 4=U, 5=W, 6=R, 7=I, 8=G, 9=M, 0=T.

A typical broadcast begins with a five-figure number repeated in cut numbers. The first three digits of this callup number used to consist of the agent's number with the last two digits containing the group count. Now, the five-figure callup is repeated several minutes, and then followed by another number which is the group count. It looks like this: DWTGI (repeated for several minutes) then DWTGI ANT (repeated for a few minutes), denoting a 120 group message (ANT=120 in cut numbers). I'm not sure if they are using five- figure agent numbers or if the last two digits in the callup have a different usage. The YL/SS voice stations have the same kind of callup.

After the callup, BT BT BT is sent and then the five-figure message groups, still in cut numbers. At the end of the message, it is repeated, and the station signs off with AR AR AR SK SK SK. Lately, these stations have been sending more than one message in each transmission.

Here are the skeds for this station. I haven't checked these for a while, so some errors may exist. Any additions or corrections are welcome. All times in UTC.

SUN           MON           TUE                     WED           THU           FRI
0800 - 7847   0300 - 4017   0200 - 6827/6866        0200 - 4328   0100 - 4506   0100 - 4330
              0400 - 7682   0300 - 4028/7528        0300 - 5416   0200 - 4018   0200 - 5115
              0500 - 6857   0400 - 3928/6768/7682   0400 - 7521   0300 - 7727   0300 - 4030
              0800 - 6786   0500 - 6857             1000 - 6786   0400 - 6856   0500 - 8065
              0900 - 6787   0600 - 5118             1100 - 4173/8066
              1000 - 4016   0800 - 6786             1200 - 6797/8137
                            1000 - 3926/6787
                            1300 - 7890

SAT
0400 - 4035
0500 - 6855
1100 - 4028/4994/6786

Due to the nature of these stations some freqs may deviate +/- one or two kilohertz. Notice that most freqs in use are perfect for propagation from Cuba to North America. Some transmissions may be aimed toward Central or South America.

These stations sometimes have "dirty" transmitters, and key clicks can be heard for a few kHz above & below the operating freq. This makes it very easy to find them when you recognize their characteristics. These stations send CW at a slow pace of around 12 WPM, which makes it easy to pick out the five-figure groups even for those listeners who don't know Morse code.

Next month we'll discuss the Cuban YL/SS voice stations.

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