F01 is a Russian digital mode numbers station that utilizes a custom FSK system compatible with ITA2 RTTY. First spotted around March 2016. Originally was given the ENIGMA ID FSK M42c.
Format
F01 messages send 5 digit groups and ends with a 2 digit serial number and 3 digit group count. The serial numbers range from 01-99 and increase by 1 with each broadcast. After it reaches 99, it cycles back to 01. Some schedules also begin with 5 group headers using the same link identifiers as messages sent via two-way communications with Russian diplomatic missions.
Recording Sample
F01 repeats 25-character blocks automatically for 6-8 minutes without any line breaks. This station also can send multiple messages within the same broadcast. When this happens, the total group count is filled up with 00000 until it reaches a multiple of 10. Then the next message is sent. If a full 5-group header was sent, only the header of the first message in the TX is distinguished using a separate block, while in the following messages it is mixed with normal message groups. (See N&0 M42 Profile)
Null messages send a single “00000” group with no outro. Test data is sent before every transmission consisting of “RYRYRY”.
=5761 00000++++++++++162 is sent for 6 minutes for null messages.
Schedule
F01 usually sends messages 2 or 3 times 10 minutes apart. Following transmissions are sent 1-3 MHz higher or lower in frequency. If a message is sent, it’s usually repeated the next day at the same time on the same frequencies.
Numbers Station Summary
Enigma ID: F01
Activity: Active
Emissions Mode: FSK, 200 Bd, 500 Hz, 5N1
Location: Moscow, Russia; Orenburg, Russia Chita, Russia Havana, Cuba
Counterpart Stations: E06, E17, G06, S06, V06, V23 M14, F06
Sources
Numbers and Oddities M42 Profile
Priyom.org Station Profile
ENIGMA Control List
http://www.signalshed.com/newsletters/En127.pdf
