ENIGMA 2000 Newsletter - Issue 29

July 2005
Articles, newsreports and Items of interest :enigma2000-owner@yahoogroups.com

M41 and “WZD”

This network was operated by the SFG (Sovjet Forces In German Democratic Republic) and the GDR Air Defence forces. Around 1970 the tracking ground stations were active around the clock on many frequencies in Morse CW and USB GG voice transmitting messages of figure strings with the preamble “WZD” - nothing else and very fast keyed/spoken. When the USSR collapsed, “WZD” disappeared and I forgot about it.

Some 3/4 years ago “WZD” showed up again - only in Morse CW and with a different structure. E2k assigned it to M41. Intense monitoring of M41 showed some further results:

”WZD” is not a callsign but a trigram in front of certain messages. The second trigram is “ABV”. The original network is embedded in other activities and most of the time behaves like any other CIS MIL network. That is why M41 rarely has been logged.

M41 uses a variety of formats: 5FG, xxx flash messages and the typical aircraft tracking data of the plotting stations in several formats (last 2 digits is msg preparation time):

WZD 1667 943 75 38 72 40 05 ABV 1667 943 75 38 72 40 05
WZD 72 251 11 66 76 00 06 ABV 72 251 11 66 76 00 06

= 447283119046006
447377688735006
447477683726006

97 00 6214 054 11
97 00 6214 064 14
97 00 6214 064 16
97 00 6214 085 16 ....

M41 uses many 4F/L callsigns, best known is PSNN. It is used in the Winter months on 4959 kHz as a marker roundslip starting at 1600z. Other c/s are YM8G, CF6U or ON8A. Frequencies are constantly changing, some are used again later on: 2740, 3301,3182, 5210, etc. Highest QRG used was 13589. M41 operates blind (BC mode) or DUPLEX.

M41 therefore is not a number station as such. It was introduced by the Sovjet Forces in the GDR and most probably was a backup network for the GDR RTTY tracking and guidance system ALMAS with its HQ in Berlin-Ost (“Fuchsbau“).

Today we listen to a sister system of RUS PVO M21, which still uses the trigram “WZD“.