[Scan-DC] Verizon Center--Digital Modulation on Biz Freqs?

[David Schoenberger]

The Verizon Center is apparently using some kind of weird modulation
on their business freqs (461.0750, 461.1500, etc.). They used to use
regular analog voice with DCS tones, but when monitoring them this
evening, the frequencies had some kind of (digital?) modulation I've
never encountered before.

Not having any kind of recorder with me, I wasn't able to record a
sample. I checked the Digital Modes Samples page
(http://www.kb9ukd.com/digital), but none of the samples matched what
I was hearing. It sounded like a buzzsaw sound, like some of the older
Motorola control channels. And no, the BCD396T wouldn't decode it as
P25.

Anyone have any idea what this could be? To hear it, you have to be
within a few blocks of the Verizon Center, as their repeaters don't
carry very far.

Thanks,
Dave