Yea I hear you, I meant to say driving up to Potsdam - not physically in Potsdam.
Pretty much once you leave Warrensburg and go through all the Lake Towns until you reach Tupper Lake you have absolutely 0 service no matter what type of cell provider you have.
On a side note, I just visited Clarkson a few weeks back and was thoroughly impressed with all the construction that’s gone on in Potsdam.