It could be from testing the towers before they turn them on or it could be what I was experiencing. When I restart my phone and turn it back on it picks up 3G for a few minutes and even has 3G speed then reverts back to 1X. I was told its because it picks up the 3G tower from either AT&T or Sprint then once it finds the US Celluar tower it conects to it since they have the contract with Verizon.
The 160 character problem is with the phone itself not signal related. My Galaxy S3 does the same thing. What the problem is the new phones they didn't program the SMS to break up the text messages automaticly into different messages. If you look at different SMS apps to download like Handcent or GoSMS Pro they are programed to break the message body down into multiple messages and send them if they are over 160.