Dang it, you beat me to it. For the same reason (just for kicks) I tried 16 and was shocked to find a signal there. I immediately came here to let everyone know. It's weak but it's on the air. I'm curious to know what power and antenna height they have.
I just made a modification to my Radio Shack double bowtie antenna, replacing the 3 feet of twinlead wire with a coax matching transformer. I also have a 6 dB inline preamp connected. I'm actually getting a signal on channel 40 for the first time.
I'm using a MyHD tuner card in my PC.
WGXA-DT 16: 21-25%
WPGA-DT 32: 53-58%
WMGT-DT 40: 44-49%
For a clear picture it needs only to be in the low 20's without dipping.
WMAZ-DT being VHF requires a different antenna, but on a good night I can get 44% with rabbit ears extended completely horizontal like a "T" and elevated.
The towers for WMAZ, WPGA, WMGT, and WGXA are all in the same location. They are on Cochran Short Route (Hwy. 129/87) at the Bibb/Twiggs county line. WGNM's tower is located a few miles north of the others. The compass direction is almost exactly 45 degrees from the Dunbar/Vinson intersection, about 30 degrees from the Watson/Houston intersection, and about 20 degrees from the Russell/Davis intersection. I hope that's helpful.
If WMGT can get their HD act together, hopefully in time for the Olympics, and assuming WGXA will be doing HD because their network is in fact supplying the necessary gear to every affiliate, then that will be the big four networks in Macon on the air with HDTV. That's a milestone for sure. There are larger cities that have worse.