Today I received a used i38HG gateway that I picked up on eBay for $25.  The seller stated that he had switched internet providers and AT&T never asked for the unit back.  I plugged it into a telephone jack, connected the power, and the iNID network automatically recognized and configured it.  I now have three of the i38HG gateways on the same network and my wireless coverage is superb. The iNID assigns each i38HG a seperate channel if auto channel selection is enabled.  I'm still not sure if it would be better to assign all three to the same channel or not. I guess I will give it a try and see what happens.

By the way, I'm getting the same upload and download speeds on all three units.  I have the 18 Mbs service and I usually average 17 Mbs down and 1.2 Mbs up.