Telstra Pre Paid Next G phone network

Hi could some one out there please explain to me the workings of the next G network. Like most people I did have a cdma phone , which I had to throw away. I had no choice i bought a next G phone LG TU550( Telstra Blue Tick Phone). My wife and i are old age pensioners we dont use a mobile phone while we are home ( we use the landline phone). WE only use the mobile when we are travelling (3 months of the year).We recently travelled Townsville ,winton, Diaminta nat Park, Boulia, Plenty Highway, Alice Sp, Ayers Rock, all gorges etc, then back to Townsville via Mt isa.My query about the phone is that in all of the distance covered we never found the reception next G, anything to shout out about. We saw telstra towers along most of the highways but no next G signal until we where close to towns. What amazed me was the reception lousy ,in the top left corner of the screen on the phone, where it tells you what network you are on , it always displayed 3G network, Why is that i thought it was supposed to be the super next G , The only place the network changed to next G was at Ayers rock near the fat cat tourist Resort. In all of that travel that is the only place the phone displayed it had changed to the next G network. Why is that so. Thank you to all people that reply to this email Kind Regards Pam & Graham