Sounds like you're describing the Central Bridge radio repeater (somebody correct me if I'm using the wrong term here...).
The talking defect detector is a few miles to the north, at CPF 503 (once upon a time known as Esperance Station). That location is pretty much next to the NY Route 30 underpass, not Junction Road.
I live within a couple of miles of this detector, across the Schoharie Valley, and hear it clearly on the scanner. Good source of info for an afternoon chase up Richmondville Hill.
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