"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 is transmitted simultaneously on two FSK channels, 2 KHz away: 50Bd/900 on 6483 KHz and 50Bd/1800 on 6485 KHz (Figs. 1,2).
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| Fig. 1 |
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| Fig. 2 |
The text is tramsitted in blocks of 718 bits using 5-bit ITA2 (Baudot) alphabet, most likely with a 5N1.5 framing which results in alternation of stops with a length of 2 and 1 bit when parsed by the editor (Fig.3).
"JULL JULL 9MR 5/9/10 RMMJ MRB MRB RYRYRYRYRY 9MR 5/9/10 RMMJ MRB MRB SGSGSGSGSG AR"
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| Fig. 3 |
The different strength of the received signals leads to think that the two channels are transmitted from two different locations; this is even more evident in Fig. 4, relating to a recording made some hours later at 2109Z.
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| Fig. 4 |