M04
| Enigma ID | M04 |
| Name | |
| Frequencies | 5748, 7250, 8188 |
| Status | Inactive |
| Voice | N/A |
| Emission mode | MCW |
| Location |
Poland
|
| Activity pages |
M04 was most recently operated by the Polish Office for State Protection (UOP). It was a Morse code counterpart to G02, and later E23. Last heard on 14 September 2000.[1]
The traffic format is given below. The speed was 19 words per minute. Standard five dashes were used for zero.
| Preamble | Message | Outro | |||
|---|---|---|---|---|---|
| U | LOLO LOLO LOLO / 01723 | LOLO / 01723 | BT BT | 89261 12616 ... 31657 | AR SK |
| Tuning signal | 5-figure message header | 5-figure message header | Fixed-length message of 100 5-figure single groups | ||
| Repeated for 3 minutes | Repeated for 5 minutes | Repeated twice | Repeated twice | ||
Full transmissions always took roughly 26 minutes.
History
Prior to April 1998, M04 used the following schedule.[2] The counting of the weeks started on the first Saturday of the month.
| Day | UTC | Freq | Week 1 | Week 2 | Week 3 | Week 4 | Week 5 |
|---|---|---|---|---|---|---|---|
| Monday | 20:00 | 5340 | x | ||||
| Tuesday | 18:00 | 4195 | x | ||||
| Tuesday | 20:00 | 4195 | x | x | |||
| Wednesday | 09:00 | 4195 | x | ||||
| Thursday | 20:00 | 5340 | x | ||||
| Thursday | 21:00 | 5340 | x | ||||
| Friday | 00:00 | 5340 | x |
The U's at the beginning were initially repeated for 10 minutes. In April 1998, it was shortened to 3 minutes.
On 1 April 1998, the schedules above were replaced, and the following schedules came into use.[3] The transmissions from now on only took place on the second Monday, Wednesday and Thursday, with the same message repeated throughout all the transmissions during the week.[4] The counting of the weeks still started on the first Saturday of the month.
| Monday, Wednesday, Thursday | ||||
|---|---|---|---|---|
| Week | 09:57 | 11:57 | 12:57 | |
| 2nd | 7250 | 8188 | 5748 | |
The final M04 transmission was on 14 September 2000, however, blank carriers were transmitted for the length of E23 transmissions on its former schedules until 2002.[1]
References
- Numbers & Oddities #32 (December 2000) [accessed September 13th, 2014]
- ENIGMA Newsletter #10 (January 1996), p. 7-8 - read a scanned version here
- Simon Mason, G2/E23 [accessed September 13th, 2014]
- Numbers & Oddities #8 (December 1998) [accessed September 13th, 2014]
Recording courtesy of Numbers & Oddities