"RY/SG" test tape continuously transmitted by 9MR Royal Malaysian Navy (RMN) [1], spotted thanks to the KiwiSDR owned by SWLOI33 in Jakarta, Indonesia. The interesting aspect is that the test seems transmitted simultaneously on two FSK channels, 2 KHz away: 50Bd/900 on 6483 KHz and 50Bd/1800 on 6485 KHz (Figs. 1,2), unless it's a bad defect in the FSK modulator.
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| Fig. 1 |
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| Fig. 2 |
The test message
JULL JULL 9MR 5/9/10 RMMJ MRB MRB RYRYRYRYRY 9MR 5/9/10 RMMJ MRB MRB SGSGSGSGSG AR
is transmitted in blocks of 718 bits using 5-bit ITA2 (Baudot) alphabet, decoded using a variable framing which results in alternation of stops with a length of 2 and 1 bit (say 5N1V i.e. a variable number of stop bits but at least one) as already specified in this post (Fig. 3) 
Decode directly in kiwisdr using the following parameters:
ReplyDeleteShift: Custom 900Hz
Baudrate: Custom
Parity: 5N1V
Best
schwed0
Alphabet: ITA2
Thanks for the comment. I agree about the variable framing, such feature was already noted in a previous post here:
ReplyDeletehttp://i56578-swl.blogspot.com/2018/12/9mr-malaysian-navy-uncommon-fsk-shift.html
I updated the post just to highlight this feature.