It would seem AT&T is slowly filling up the gap between Knoxville, TN and Lebanon, TN along I40. A year ago AT&T put out a press release indicating that they were building out 525 additional 3G cell sites.
Within the last few weeks they have turned on towers extending west on I40 from the previous cut off at around mile marker 366 so that there is now complete 3G coverage from Knoxville west until around mile marker 339. This is the first noticeable east-west coverage expansion along I40 in the last 2 years.
For the first time EVER I had bonafide 3G AT&T coverage in Cumberland County. Granted the county line is at Exit 340, so I only had coverage for a mile on I40, but still ANY coverage at all is an improvement. Just inside the county line I pulled over and ran a speed test. I did get 1080 Kbps down and 223 Kbps up, with two bars of signal on my iPhone 3GS. I doubt that the cell site I was using was in Cumberland County. Most likely it was located on Mt. Roosevelt over looking Rockwood.
Presumably this now gives 3G coverage to the communities of Kingston, Rockwood, Harriman, and Midtown.
It still seems that AT&T hates Crossville and Cookeville. While I understand that it would have been odd to light up these cities with 3G without connecting them to the larger 3G markets, it should be noted that if you combine the total populations of Kingston, Rockwood, Harriman, and Midtown it would be less than half that of Crossville, and one quarter that of Cookeville.
My last trip to Nashville still had 3G single in that market cutting off at around mile 243. These means that the AT&T coverage gap has dropped from 123 miles to 105 miles. I will be in Nashville on December 17, 2010 and I will test at this time if the coverage has expanded eastward anymore to coincide with the westward expansion from Knoxville.
With CDMA 3G already in Cumberland County (Verizon, Sprint, and US Cellular), and 4G (marketing term, not real 4G) in Nashville (Sprint, Wimax, and Verizon LTE) AT&T is losing ground in this area.
As of December 5, 2010 this coverage is not included in the online AT&T coverage map at http://www.wireless.att.com/coverageviewer/ however this report is based on first hand observations.