Morse code spooks

After some recent discussions with two friends Rich & Dave I have been playing with WebSDR, decoding all sorts of transmissions using MultiPSK. I have never been particularly interested in amateur or “ham” radio but receiving and decoding signals from around the world is a fun way to pass a cold evening.

There is lots to find: weather information, humorous IRC style chat, worldwide operators trying to reach as far as possible and even digitally coded pictures.

However tonight I stumbled upon 4594Khz which has an almost continuous stream of morse code (CW) that is in a rather unusual format. After a recent trip to Bletchley Park where I was fascinated by Colossus, the Bombes and other cryptographic breakthroughs the text from 4594Khz stood out instantly in 5 letter groups.

A very short sample from tonight (6th Feb 2012 @2150 UTC) is below:

   ORGYO OAIPF KWLLZ AJDI LSZHO PWDIZ SKHTX POIOJ RENKT BAFFH EKCHG
   DRMSW BJTQT MPJOL SBQDG FUKIX == AA GR 08 == UPUHP QQCUQ IOYNJ SFCRJ
   WGSMB GXHDA GDLGC UXEPU RYLXZ BIFCX CXOTJ XAYZL COFWO ADYAH PGNWD
   DISYU GXHND BHYZBNCUM PANFK OFPBN FAJMI SXPIF PWWNA WQRIB DWDEH BCGQW
   WPHA R LCOUP FILES SWNJK CNFSU NUZNN BBPHH == AA GR 021 = TXUIA =
   NR 461 KQ V TA5N 553160 PR2Q GR 121 == AR AR VVV DE 4XZ 4XZ = =
   VVV DE 4XZ 4XZ = = VVV E 4XZ 4XZ = = VVV DE 4XZ 4XZ = =
   VVV DE 4XZ 4XZ = = VVV DE 4XZ 4XZ = = VVV DE 4XMI4XZ = =
   VVV DE 4XZ 4XZ = = VVV DE 4XZ 4XZ = = VVV DE 4XZ 4XZ = =
   AR R NW QTC 1 NR 371 = = NR 371 LT V WF5N 5H2260 AN0H GR 2 ==
   AHAHA AIMUF SENCO SANHT HTTRX WLZK LMEJR TRXMT SNENX SNMGK MLYIL SEZSQ
   NIHTTM BBQNX DXQJZ TMCTQ UZBPD WMGQF RQMYP NJHKX ZFXDH XTOYR LKFDT QSNAR
   JHTCE AIMUF == NR 371 LT V WF5N 532260 AN0H GR 62 == AHAHA AIMUF SENCO
   SANHT HTTRX MWLZK LMEJR TRXMT SNENX NMGK MLYIL SEZSQ BHTTM BBQNX DXQJZ
   TMCTQ UZBPD WMGQF RQMYP NJHKX ZFXDH XTOYR LKFDT QSNAR JHTCEAIMUF ==

The distinctive groups suggested to me that it was some form of encrypted text, broken up easily for transmission by morse. A quick Google search reveals a PDF entitled “Numbers & Oddities a.k.a. the Spooks Newsletter” and an excellent write-up about “Israeli Morse Station 4XZ (M22)”.