Cuban numbers/data Station
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ka3jjz
Wiki Admin Emeritus
Please, always post the frequency along with the time...thanks...
Token
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This is the Cuban hybrid (both voice and data) numbers station designated HM01. DIGTRX can be used to demodulate the data.
T!
T!
Token
Member
You ain't missing much. The data is encrypted so about the only thing demodding the data will do is give you an encrypted text file. I have heard that once or twice the Cubans failed to encrypt SK01 transmissions (the data only cousin to this transmission) and that listeners demodulating did get recognizable words, but even that was not quite clear text as it did not make much sense.
About the only thing I can think demodding this data would be useful for might be to see if the same message is going to multiple recipients or is being sent multiple times/days to a given recipient. Demodulating these signals serves about the same purpose as manually recording verbal numbers stations, you are never going to know what the message is but you might see certain trends...if you care to.
I occasionally will run DIGTRX during either HM01 or SK01 transmissions, just to confirm the format is still the same, but that is about it. I don't often listen to any of the V02/SK01/HM01 Cuban stations myself, catching maybe a couple per week on accident. When I do actually look for numbers stations (maybe 5% of my listening time) it tends to be the less well known and understood Asian stations.
T!
Yep, I usually get the Cubans booming into my qth, so I can easilly spot them. I've never really caught any of the European Numbers Stations, probably because they are becoming rarer these days. I think I've seen you posting on HF Underground, chasing pirates, LOL...Gotta love radio.
Steve
Steve
W2WP
Member
AM I assume?
Actually, they are broadcasting very wide, double side band maybe? but I get them equally well in am and ssb. But, the video I posted was in USB.
Steve
Steve
W2WP
Member
Thanks Steve.
Token
Member
HM01 is most generally full AM, DSB plus full carrier.
They (all of the Cuban stations, voice V02a, data only SK01, and hybrid data/voice HM01) occasionally will be in some other mode, either USB or LSB, probably in error. The most common mode for them to use other than AM is LSB. This most frequently seems to happen after the same transmitter has been used for an CW (not an MCW) M08a transmission. Remember that most M08a transmissions are MCW, full AM transmissions of 1 kHz audio CW tones, but some time slots appear to be in ICW, “regular” CW.
One theory on why this happens is that M08a does not transmit honest ICW at any time, but rather uses a 1 kHz tone modulating a transmitter in LSB. This causes what looks like ICW but the center frequency of the CW is shifted down 1 kHz form the tuned frequency of the transmitter. This is easy to determine as audio harmonics of the 1 kHz tone are often present when the Cubans do this, stepping down in frequency only, with none on the high frequency side of the CW audio.
So, the theory is that after an M08a CW transmission using the LSB transmitter the operator occasionally forgets to select AM before beginning the next transmission, resulting in a few LSB transmissions of V02a and SK01. So far I have never seen an LSB HM01 transmission myself but have heard of others seeing them. To be honest I do not pay attention to the Cuban numbers stations so I only catch a few a week, mostly accidentally.
Also, but much less commonly, V02a, M08a, and SK01 have been seen using USB. Again, the assumption is this is in error. Yes, Pedro (the fictional engineer for the Cuban numbers station transmission site) often makes mistakes. I have even seen, and recorded, a transmission that started in LSB, switched to USB, and ended in AM.
T!
They (all of the Cuban stations, voice V02a, data only SK01, and hybrid data/voice HM01) occasionally will be in some other mode, either USB or LSB, probably in error. The most common mode for them to use other than AM is LSB. This most frequently seems to happen after the same transmitter has been used for an CW (not an MCW) M08a transmission. Remember that most M08a transmissions are MCW, full AM transmissions of 1 kHz audio CW tones, but some time slots appear to be in ICW, “regular” CW.
One theory on why this happens is that M08a does not transmit honest ICW at any time, but rather uses a 1 kHz tone modulating a transmitter in LSB. This causes what looks like ICW but the center frequency of the CW is shifted down 1 kHz form the tuned frequency of the transmitter. This is easy to determine as audio harmonics of the 1 kHz tone are often present when the Cubans do this, stepping down in frequency only, with none on the high frequency side of the CW audio.
So, the theory is that after an M08a CW transmission using the LSB transmitter the operator occasionally forgets to select AM before beginning the next transmission, resulting in a few LSB transmissions of V02a and SK01. So far I have never seen an LSB HM01 transmission myself but have heard of others seeing them. To be honest I do not pay attention to the Cuban numbers stations so I only catch a few a week, mostly accidentally.
Also, but much less commonly, V02a, M08a, and SK01 have been seen using USB. Again, the assumption is this is in error. Yes, Pedro (the fictional engineer for the Cuban numbers station transmission site) often makes mistakes. I have even seen, and recorded, a transmission that started in LSB, switched to USB, and ended in AM.
T!
Token
Member
This is a numbers station. Most numbers stations are voice or Morse code, with a few data stations, this one happens to be a hybrid of voice and data station recently adopted by the Cubans. Like all numbers stations the purpose for the stations existence has never been acknowledged. In fact, as far as I know none of the currently operational numbers stations have ever been acknowledged by their source nation to exist at all.
The most prevalent belief is that these stations are secure one way links to intelligence assets in the field. Yes, messages to spies.
Interestingly enough in the case of the Cuban numbers stations (there are 4 different formats known to be used by the Cubans, voice, Morse Code, data, and hybrid voice and data) there is actually court documentation to support that these stations are messages to spies. In the US, in at least 2 Federal cases in which charges have been filed, the defendants are said in court documents to have been receiving direction via such transmissions.
Numbers stations have a long history and can be mildly interesting to track / observe. A simple Web search will result in many, many, thousands of hits for information. Unfortunately, amongst the good information, there is a bunch of really out there stuff to be found also. But, it all must be true, because it is on the Internet….
The most frequent question I hear in regards to these stations is “why would they do it this way”? This is a very secure method of message delivery. It is one way only, but the recipient is about as anonymous as it is possible to be. For example, there is literally no way to tell how many, and who, received this particular transmission. Pretty much any other method of message delivery would bring at least some danger to the recipient. A phone call, even with a burn phone and multiple cut-outs, leaves an electronic trail. The same thing with emails, even to anonymous servers. Having to visit any electronic location, such as a web site, to read a message leaves a trail. The same with more pedestrian forms of field craft, such as dead drops. Each requires the recipient to expose themselves to detection and observation.
With a numbers station the recipient has to expose himself to get the key, but after that he is secure for however many messages he got keys for. He can be updated daily without exposure.
Well, that is one theory, anyway …
T!
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