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.