32.507163,-89.998350 is where I am at. Two of the Rankin County antennas are not far across the water from me but Canton is closer but I get nothing.
Are you receiving the control channel for the Canton site? If you haven't already done so, you may want to use the analyze function of the sds200, or do a site hold to confirm.
Has anyone confirmed the frequencies in use on the Canton site (and other Madison County sites) recently? There are several frequencies listed on the license for the Canton site that are not included in the RR database. Is it possible that the control channel has changed? (I'm not in the right part of the state, or I'd throw DSD+ on it)
You may want to add 770.36875, 770.61875, 770.86875 to the Canton site to see if you get something.