HFU HF Underground
Loggings => Utility => Topic started by: R4002 on November 15, 2018, 1128 UTC
-
Very strong Link-11 aka STANAG 5511, TADIL-A - tactical data link on HF - Link-11 signal on 6942 kHz (when tuned in USB mode). Signal is S9+10sb to S9+20db. Usually I see Link-11 with two signals side by side (no carrier, so DSB?) but this one is a single signal - center of the signal is 6943.6 kHz or 6943.7 kHz.
Heard early morning US East Coast time (0625 local, 1125 UTC) on the ΣSDR KiwiSDR on the CT/MA border.
-
When they're on upper and lower it's isb, independent side band. This allows for having two exclusive data streams simultaneously.
-
Actually, the transmitters are capable of DSB also, the same data on both sidebands. So unless you look at the data itself it can be hard to tell if it is DSB or ISB.
In the case of the signal reported here (at least on the evening of the 15th) the signal is on 6942.0 USB (for Link-11 CLEW when properly tuned the Doppler tone is at 605 Hz). I have seen other freqs used in this area, as well as both DSB and ISB.
T!
-
I suppose they can do a form of diversity with having both channels pushing the same data.