Marine Tac 10 is being used for boat patrols on the Potomac and Anacostia rivers in support of Inauguration security. Heard a unit this morning checking in with "Tac-com" on Marine Tac 10, advising they were beginning their patrol, and will be using PG County "Mike 1" as their working channel. I'm assuming "Mike 1" is Marine 1, tg 9101 on the PG County 700 system. I've noticed that Marine 1 is also active on the DC 700/800 system as well. Not sure what system Marine 1 actually lives on, as most NCR jurisdictions have that channel designation. Maybe it uses several depending on what zone it is accessed from?
As for Marine Tac 10 being carried on the FIRST Anne Arundel simulcast, the field units must be accessing it using the PG system via ISSI - or possibly via the Wave app on their FirstNet smartphones.