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Request for a raw message

Mats A
 

Hi folks.

I was scanning YaDDNet and found some interesting TEST messages from a ship.
ALL SHIPS TEST messages with EOS!?
It just blows my mind why it is even possible to compose such a message, or is it just a unique sequence of bad decodes?

Unfortunately neither of these messages reached my receiver.
May someone provide the raw message for some forensics?

Best regards
//Mats

Richard Ware
 

On 4 June 2018 at 22:15, Mats A <omnia@...> wrote:
Hi folks.

I was scanning YaDDNet and found some interesting TEST messages from a ship.
ALL SHIPS TEST messages with EOS!?
It just blows my mind why it is even possible to compose such a message, or
is it just a unique sequence of bad decodes?
---------------------------
Hi Mats

I wasn't logging at that time, but here's an ALL SHIPS message I
logged some time ago, complete with EOS

Is this any help? I delete any 'from ships' messages unless they're
from shore establishments with ships' MMSI numbers, so I don't have
the full message unfortunately

TIME: 2018-05-24 23:39:50 FREQ: 2187.5 DIST: -- Km
SYMB: 116 116 108 047 076 038 090 000 118 126 126 126 126 126 126 126
127 112 127 127
FMT: ALL
CAT: SAF
FROM: SHIP,477638900,???
TO: ALL SHIPS
TC1: TEST
TC2: NOINF
FREQ: --
POS: --
EOS: EOS
cECC: 112 OK


Rich

Mats A
 

Hi Rich and all,

After some forensics, it seems as the message is a all ships safety call mixed with Tc1 set to TEST.
The ship seems to have been built in 2012, and i guess that ITU-R M.493-13 would have been applicable at that time.

AFAIK, this kind of message shall not even be physically possible to compose at all, and it's a mystery it even exist.

Do someone else have messages to compare with?

//Mats

Richard Ware
 

On 5 June 2018 at 19:20, Mats A <omnia@...> wrote:
Hi Rich and all,

After some forensics, it seems as the message is a all ships safety call
mixed with Tc1 set to TEST.
Do someone else have messages to compare with?
-----------------------

Here's another one plucked from my session logs

Not only has this herbert asked the world's shipping to meet him on
2187.5 for phone comms (not the best idea, Matey!), it looks like
2187.5 has become 21875.0
Panamanian flag. That explains a lot.

TIME: 2018-04-28 23:38:37 FREQ: 2187.5 DIST: -- Km
SYMB: 116 116 108 035 052 053 000 000 109 126 021 087 050 021 087 050
127 086 127 127
FMT: ALL
CAT: SAF
FROM: SHIP,355253000,???
TO: ALL SHIPS
TC1: J3E TP
TC2: NOINF
FREQ: 21875.0/21875.0KHz
POS: --
EOS: EOS
cECC: 86 OK

Rich