[Spooks] How to decypher this cyphered message

[Valentin - Tito]

Hello. Im new to the list. Last night at 22.05 UTC Iheard one station on
4.461 USB. It was a female voice.
She was telling many times 3 letters: FTJ, FTJ, FTJ,etc...
Then she told "message 105".
After told "text" and started with all this words:

OEVCF
RUCOM
UDSVY
VPZOX
CJNDG
CBXYQ
SIKXU
VVEMM
JBWFV
POBXL
ABKLL
MQGPZ
QLDSB
QFVHW
UETAG
DARNP
FIPDW
.............

I have some questions:

1) Where is this woman transmitting from ?
2) What does "message 105" mean ?
3) Any tip to decypher this message ?

73 de Tito