Is this is what numbers stations are like now? There was a female announcing in Spanish, four or five numbers, then what sounded like digital data transmitting. That would last about a minute or so, and she would come back on with a new set of numbers. Transmission was clear here in the US northwest, about as clear as Radio Habana Cuba usually is. I started listening at around 1012 and it ended around 1022. I recorded a snippet but I must not have something set right with HDSDR/Soft66LC4 as it sounds way off frequency in the recording.
This is what one specific numbers station is like, but not numbers stations in general.
Without a recording I cannot be sure, naturally, but what you are describing sounds like Cuban numbers station HM01. The Cubans started using this format mid last year (2012) and it is a combination of the previously used voice numbers station V02 and the digital numbers station SK01. It has been a while since I heard either SK01 or V02 and I suspect that HM01 has either replaced them or is in the process of replacing them.
If it was HM01 it was Spanish language (SS), female voice (YL), and 5 figure groups (5f), followed by a text file sent using the RDFT format. The transmissions actually start with 6 different five figure groups sent over and over, no data, for several minutes, it then goes into the 5f / data alternating pattern. The 5f sent before the data will be one of the 6 five figure groups repeated in the first part of the transmission. The transmissions are about one hour long and typically start just before the top of the hour. You say you heard it from about 1012 and it ended about 1022 (I assume that is UTC time on a 24 hour clock). This means you tuned in after the transmission started and did not hear the first “numbers only” portion, the first 10 minutes of an HM01 transmission can be found here:
Numbers Station, Cuban, HM01, 17540 kHz, AM Mode, January 19, 2013, 2258 UTC - YouTube . Also, the transmissions consist of more than one message body (new 6 five figure groups and data transmissions), between each message body is an extended pause. What you thought was an end at 1022 was most likely a pause between groups, and a new message body would have started had you continued to listen.
And the station would be “about as clear as Radio Habana Cuba usually is”, since they likely use the same transmitters
Also, how sure of the frequency are you? I have never heard this signal on 9150 kHz, but I have caught the station on 9155 kHz in the 1000 UTC hour several times. You say you were using a Soft66LC4, was the line of the signals carrier on 9150 kHz, or were you just in AM mode, tuned to 9150 kHz, and hearing the station there?
T!
(edit) DOH! I was writing my response while Bruce was posting his.
