New York City FIO2

For a while now, I had confirmed that 171.1750 MHz, N653 was officially designated as NYC Federal Interop 2. However, I had never heard anyone using it.

But when I arrived in town this last week, I heard a couple of days of traffic from some group moving around the NYC area. They were a large enough group that they had to take separate ferries when they were using the Staten Island ferry. It sounded like some sort of escort. The only call sign I caught was "1A7", so no idea what agency it was. I did also hear "Topside" a couple of times, but not sure if it was a call sign or just telling someone where they were on the ferry!