for those out there interested in HF here's a nice explanation of the DHS COTHEN network that was posted on another list. This was in response to newcomer's question about the COTHEN network.
Hi Bob. I monitor COTHEN daily and the 2023 frequencies are still in use. I use PCALE to scan the frequencies and decode the ALE. I also run SORCERER because PCALE has some mis-decodes that SORCERER correctly decodes. There is some clear voice traffic after ALE handshakes. Most of it is routine consisting of USCG aircraft requesting COMCOM Chesapeake (LNT/PAC ALE identifiers) assume their radio guard and the terminating guard upon landing. Routine position reports are also sent by the aircraft. There is also clear voice after ALE handshakes between The TCS (Technical Service Center Orlando FL) and various COTHEN users test radios both in the clear and encrypted voice. There is also clear voice after an ale handshake between USCG assets and District Commands. While most traffic on COTHEN is routine, it can also be SAR, law enforcement and hurricane related and very interesting to hear. There is also some clear voice comms from Customs and Border Patrol aircraft with their ground stations through their COTHEN communication expansion nodes. The problem is attempting to follow the communications over-time since they frequently change frequencies to the best available frequency. The voice is also weak at times and hard to understand. As mentioned, you can also sit on a frequency and hear whatever traffic appears on that frequency. The majority of the signals will be ALE sounding which can be annoying at times. Good day light frequencies are 10242, 11494, 13312, 13907, 15867, 18594. Night frequences include 11494, 10242, 8912, 7527, 5909.5 and 5732. I have a day light and darkness set of frequencies I can with PCALE. The bottom line is there is some interesting listening, but it requires lots of patience