I have heard of these stations, but had never heard one on the air. It is in Single Side Band (SSB). The first voice was female, repeating sequences of letters in the NATO alphabet. Another voice came on, this one male, beginning at 7PM US EST time. This second station likely was not collocated with the original because the signal was much weaker. Some websites identify this as a Strategic Command frequency, which makes it even more interesting. I will have to continue to monitor this one regularly.
Interesting to finally catch one of these stations on the air.