HFU HF Underground

Loggings => Utility => Topic started by: flexoman61 on October 25, 2015, 1525 UTC

Title: several EAMs 15016 usb voice w/RTTY 1500 UTC 25OCT2015
Post by: flexoman61 on October 25, 2015, 1525 UTC

Another broadcast at 1516 utc.
And a 3rd broadcast at approx. 1527utc.

recording available.

Voice:

"Four Bingo Blackout.."

The usual-echo, mike, papa but with RTTY (?)

"....Fallback OUT"

RTTY:

VTOMM
ILCVOMICNVV LIV GML C  MMCVMCVIL TN
VITVT O
 IPMM VV
VVTV
CMV V LMT
TM:88:)
8
;
,.-TITMITN
V55
 L
MTVNMGM
NW TLV
TIO
MIMV MLL
V I
CVM MTVCLLL
MTTMMT
TVV NVNMOAMMMNL
MMVU AALVV NT LMVVTOON
UNMT T
MCTGASMV
LTMMLLNOXOM
MP
IOMMQM
CLL

Title: Re: several EAMs 15016 usb voice w/RTTY 1500 UTC 25OCT2015
Post by: Token on October 25, 2015, 1900 UTC

These transmissions on 15016 were, naturally, in parallel with the other HF-GCS frequencies, 4724, 6712, 6739, 8992, 11175, 13200, as well as 15016 kHz.

The RTTY has periodically been present for years now.  While no one is sure why it is sometimes present it appears to be accidental in nature, possibly audio crosstalk in the HF-GCS audio system.  This RTTY is STANAG 4481 FSK, and it is KG84 encrypted.  This KG84 encryption is part of the reason it can strongly be assumed to be accidental.  To be successful the encrypted RTTY must include a 64 bit header, message blocks, and End-of-Message block.  Typically the RTTY on HF-GCS starts a few seconds before the voice audio message and almost never start with the 64 bit header, meaning the transmission starts in the middle of something.  If i was intentional on these frequencies it would almost certainly start with the header.

T!