Just noticed it tonight ... strong signals into DFW area ...
No idea what system or service these transmissions are associated with, but, the spectrum is normally marine.
Also, using Spectran, the following characteristics were noted:
Occupied BW: 650 Hz .. 2850 Hz (Rcvr IF BW set for 3 kHz, Rcv freq = 2.000 MHz)
Startup (training sequence) carriers:
790 1090 1160 1460 1760 1840 2130 2430 2510 2810
OFDM data carriers every 60 Hz (yeah, I know: line rate) or so ...