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HM01

Enigma ID HM01

Spectrum image Spectrogram

Name
Frequencies
Status Active
Voice Female, automated, with Cuban accent
Emission mode AM; RDFT
Location Havana, Cuba

Flag_Cuba

Activity pages

Download audio sample

Known counterpart stations

HM01 is the core shortwave operation of the Cuban DGI. It is a combination of and the successor to the analog voice V02a and the digital SK01.

Format

Preamble Message 1 Message 2 Message 3 Message 4 Message 5 Message 6
17568 92788 76627 50636 44143 14766 Sync tone 17568 RDFT
92788 RDFT
76627 RDFT
50636 RDFT
44143 RDFT
14766 RDFT
Six 5-digit message headers   First header   Second header   Third header   Fourth header   Fifth header   Sixth header  
Repeated for 3 minutes   Repeated for 20 minutes

The digital mode used by HM01 is RDFT (Redundant Digital File Transfer). It was originally developed for amateur radio use; however, it was adopted by the DGI in 2007. The data bursts, created using the DIGTRX software, encode binary files with 8-digit file names, and either .TXT, .F1C, or .F1G as the file extension.

The spoken message headers consist of the last 4 digits of the respective file names, followed by a bogus number. The last digit previously acted as an age counter, increasing between 1 and 8 inclusive every day, after which the message was replaced on the given slot; on newly added messages, the digit 1 was sent for two consecutive days.

Scheduling

HM01 broadcasts the same set of six messages on all schedules, starting at 16:00 UTC, and concluding at the end of the 10:00 UTC schedule the next day. The transmissions take place on the hour and at the 30-minute mark, with only a blank carrier between the two airings.

Behind the scenes

HM01 uses the same facilities as the international broadcaster Radio Havana Cuba. It is not uncommon to hear the Radio Havana Cuba audio feed being broadcast on the HM01 frequencies by mistake.

HM01's audio feed comes from a computer running Windows XP.

Windows XP log-out and log-in sounds prior to a late transmission, 3 June 2014, 21:34 UTC, 16180 kHz

HM01 has been heard on the schedules of its sister station M08a, either replacing it completely, or mixing into the M08a audio feed. The same has been noted vice versa.

HM01 mixing with M08a, 18 June 2014, 23:00 UTC, 8010 kHz

History

HM01 was first heard on 18 November 2012, initially on the V02a time slots that existed at the time. In early 2013, the current schedule style developed.

In early 2014, HM01 dropped its 23:00 UTC time slot, which used to be the following:

UTC Mon Tue Wed Thu Fri Sat Sun UTC
23:00 17540 11530 17540 11530 17540 11530 - 23:00

In mid-2014, HM01 replaced the frequency 12120 kHz on the 09:00 UTC time slot with current 11462 kHz, and also introduced this frequency as an alternative for 05:00 and 06:00 slots. On December 1st, 2014, HM01 replaced the 06:00 UTC slot frequency on Tuesday, Thursday and Saturday with 9330 kHz - formerly 14375 kHz. The schedule has remained unchanged since then.

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