20 June 2019

unid QPSK 9KHz 4800Bd

Just working on the wideband signal spotted by Christoph first on 10160.0 KHz (cf) and more in detail discussed here in his blog. Replied his same results: period consisting of 984 bits (492 symbols) and 24-bit long sub-frames. As a further detail, I want just to add how the sub-frames seem to use different polarity.  Same result also for the geo location of Tx site (prob. Luxembourg).
Thanks to Christoph for reporting and sharing.

Signal recorded using the KiwiSDR owned by IW2NKE in Italy.

3 June 2019

STANAG-4285 1200bps/L in async mode

Interesting recording of STANAG-4285 1200bps/L blocks which transport 8N1 framed streams (async ops).

Fig. 1
After demodulation (I preferred to use my Harris RF-5710A modem), each block consists of 476 bytes of data and share the same header (Fig. 2):
00 52 00 00 A4 3A 29 21 5C F0 01 4C 00 00 00 00 00 00 00 F2 40 19 77 E6 ...
don't know what the "signature" could be (encryption, compression, protocol encapsulation...), anyway the messages are not sent in clear-text.

Fig. 1
Recording picked up on 7559.0 KHz/USB using http://swloi33.proxy.kiwisdr.com:8073/