A strange as unid signal appeared last week on about 5458 KHz (1730Z) and 15200 KHz (1629-1700Z), both apparently using USB (Figure 1); the first was logged by cryptomaster and the other by Philby (Nicolas, from dxuti.fr), they kindly sent me their recordings.
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| Fig. 1 |
Although the type of emission is different (continuous and burst mode) some characteristics suggest that they are the same type of signal. Figure 2 shows that the continuous signal has a period of 71 msec conisting of six frames, each consisting of 12 msec.
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| Fig. 2 - periodicity and frame structure of the continuous-mode signal |
Looking at the 15200 KHz recording, each burst lasts about 333,34 ms and is characterized by a 71.4 ms period, each period consisting of six frames of about 12 ms. Notice the different speeds of the header and the body (Figure 3).
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| Fig. 3 - periodicity and frame structure of the burst-mode signal |
No idea about the purposes and the user, maybe a kind of alignment signal... really don't know, at glance, strings of "01"s... but I could be wrong: some unid signals emerge during this war times.
As for locating the Tx site, my friend Philby attempted a TDoA search which resulted in a site near Lake Urmia (Fig. 4): the lake is located between the provinces of East Azerbaijan and West Azerbaijan in Iran, and west of the southern portion of the Caspian Sea. It's interesting to notice that near this location you may find a combined Mil/Civ airfield hosting a IRIAF (Islamic Republic of Iran Air Force) composite unit helicopter/transporter aircraft as support of the border regiment of Urmia.
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| Fig. 4 |
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