Here San Luis Obispo, California I have some HF-GCS observations. I don't know much about this; TNX AGN Token for ID'ing.
in progress 11,175 kHZ USB 23:19-23:21 UTC June 1 2010
phonetic letters; fair signal through heavy local broadband QRM
in progress 13,200 kHz USB 23:29-23:33 UTC June 1 2010
phonetic letters, occassional number, "I say again", "Stand-by"
distinctive final dual tone pips- good signal
in progress 13,200 kHz USB 23:49-00:03 UTC June 1-June 2 2010
noted final dual pips sent twice between small amount of traffic
complete transmission, simultaneously on:
13,200 kHz, 11,175 kHZ, 15,016 kHz ALL USB 00:15-00:18 UTC June 2 2010
Identifying final dual pips, good signals.
My impression is that these are un-recorded messages, read by operators who don't know the actual content. As this appears to be one-time encryption, usually reserved for the most sensitive traffic, I consider these Number Stations. Unlike typical Numbers Stations that tend to transmit on the hour or the half on some fixed schedule these transmissions to the best of my limited knowledge have no fixed schedule.
Try: 4724 kHz, 6739 kHz, 8992 kHz, 11175 kHz, 13200 kHz and 15016 kHz ALL USB
I have had the best luck so far on 13200 kHz USB; sooner or later you will observe it.
Cheers