ENIGMA 2000 Newsletter - Issue 12

September 2002
Articles, newsreports and Items of interest : e2k_news@hotmail.com

CW Beginners' Corner

(Part 2,provided by CR)

The intricacies of the M13 Family XV

This is a very large organization with a very complicated schedule of frequencies for a large number of recipients. There are 3 voice stations in the same family, E18, S04, and G22, but the majority of them are sent in Morse.

Morse speed is fairly slow at around 8 to 10 WPM, so is fairly easy for those only just learning morse.

The first logs of this station I can find are in June 1993, but it seems that from the serial numbers of the messages, if they started at 001,that it probably started transmissions about 1985. I would be interested to know if anyone has any logs prior to June 1993.

When I first started logging them in 1996, I understood from the old ENIGMA that the transmissions were random, but over the years I have established that there is a pattern to the transmissions, so they can be predicted in the majority of cases.

I have found that they transmit on the same days of each month, and the frequencies, although they change each month, are used on an annual basis, that is the frequency used this September will be the same in September 2003.

They use a bewildering range of frequencies and can appear anywhere Between the lowest frequency logged, 3168kHz, and the highest, 13416kHz. Quite often they TX in the Broadcast bands, which seems strange as they are often lost underneath a very strong broadcast signal. (at least in UK/Europe, Ed)

The majority of them transmit on the hour, but others have been logged at H+10, H+15, H+20 and H+30.

M13

Format of transmission is, XXX 3 figure ID sent from between 2 to 6 minutes

= 246	( message number, advances by one next month. )
21 =	( Group count )
	20 single 5 figure groups, short zero =
XXX	sent 12 times
= 246 20 =
	(message repeated )
= 000

Times of transmission again can be varied, changes to 1 hour later when clocks change in October, (from UK BST to GMT) some of them have been heard sending their first transmission in the early hours between 02.00z and 05.30z, these are then repeated in the evening of the same day. My own theory is that all of them, apart from one, send the message first in the early hours then repeat later. (an ongoing investigation, Ed)

They have also been logged during the day at 07.00 08.00 09.00 11.00 12.30 15.00 and 17.00z.

The primary times are between 19.00 and 22.00z and one can be heard every day at these times.

There are 4 distinct groups in the family, the first, using the ID's 253 254 272 284 378 411 417 458 501 517 714 746 757 823 and 975 just send 1 message each month. These are sent on the same days of each month and are repeated 2 weeks later. The messages are sent sometimes twice each time and sometimes 4 each time.

Repeat sequences that have been logged:-

On the same day 1 Hour later on the same frequency.
On the same day 1 Hour later on a different frequency
On the next day at the same time on the same frequency
On the next day at the same time on a different frequency
On the same day 2 Hours later on the same frequency and also the next day.

Apart from one ID, 272, messages are sent on 2 days.

A subdivision of this first group is the ID 346, this is only sent once a month.

The further subdivisions are:-

2, ID 261 can send more than one message a month, it uses 2 IDs, 261 for short messages of 16 to 23 groups and 590 for longer messages.
3, ID 679,short messages, which uses 281 for longer messages.
4, A transmission sent at 15.00 and 17.00z which changes ID each month.

M13a

Format of transmission is "XXX XXX XXX 000", which can be confused with M12. Also changes ID each month, and in addition to this has an 03.00z transmission which uses another, different, ID.

M13b

Again uses a different ID each month, can send more than 1 message in a month and uses the type "a" call for short messages and straight 3 figure call for long messages.

M13c

2 x month schedule, 1st/3rd Wed & Thurs (22.00z variable) Uses a different ID each month and is possibly sent from a different transmitter. (commented on by a number of monitors, Ed)

The morse is sent in MCW and is faster and of a different rhythm to all other M13's

M13d

(Ed note:- see Issue 10)

Has only recently been discovered by a listener in the USA.

As far as I can tell has only been heard at 0230z, despite intensive monitoring at other times. It does not follow any of the "usual" patterns and used the same frequency in the 2 months following discovery, in July 2002 it TX'd 3 messages.

Format of transmission is "XXX ID for 5mins, BT, Mssg No, Gp count, BT"

Uses 767 for short messages and 303 for long messages.

Some of these can be very long, the longest recorded message for an M13, to date, was sent by this station:- 469 groups, taking many hours to transmit.

The following applies to all the M13's :-

The ending used to be 3 long dashes, but for a period in 2002 the messages were hand sent, and now the ending is 3 short zeroes. I suspect that a new machine has been brought into use which accounts for the change.

Errors are very rare, in all my years of monitoring I have only heard one, and that was very recently.

On Friday 5 July at 2000 there was a transmission to 253 on 12884, at the same time the other schedule on 8153 which should have been to ID 284 was being sent as 253 with the same message. The message was sent complete.

The second sending 2 weeks later had the correct IDs and messages.

A new schedule was heard on 2 July 2000 ID 118 at 1900 on 8215. The second sending on 16 July was not heard, so this may possibly be one that only sends once a month, or even be like ID 123 that can be on any day or time. Until I get more information I will not be sure as to where in the family that these can be designated.

ID 123 is very elusive and apart from one instance does not seem to have any regular skeds or frequencies. I have so far only logged it on the following dates, with message serial number and group count. Note that it does send long messages.

2 May 1999 at 2000, Frequency 5315, Serial 114 GC 124,
7 May 1999 at 2000,frequency 5315, Serial 115 GC 60,
1/2 June 2000, at 2000, frequency 5422,serial 134 GC 52,
2 April 2001 at 0800, frequency 9998 Serial 143 GC 138,

then again one year later

1/2 April 2002 at 0800 on 9998, serial 155 GC 88.

You will note that the serial numbers increase, so it must be on each month, but I have not heard it since April 2002

I still feel that there are other schedules to be discovered and all logs are very welcome by Enigma2000, and a CC to crripwnr@supanet.com would be appreciated.