This site will show all local Telstra towers in Australia... It beats guessing where you have reception!
www.cellsite.nudge.id.au/
Now:
1. Scroll down to the bottom and 'Jump' to your state.
2. Scroll to the local area.
3.
Zoom into the 2km or less scale and any Telstra towers will appear. You may need to scroll around the local area to find any.
I'm no expert, but frequently use both my mobile and modem in the NT and remote QLD.
My personal experience has been:
With Modems.... If I was over 35+kms (theoretical) or 25kms (in reality), as the crow flies and an interrupted line of sight, I have no chance. Depending on local conditions, 5/15+kms can start to pull me up without a good external antenna.
With Mobiles... Subject to the local conditions.... I'm generally fine to about 10/25+kms and then may need the external antenna. In good locations 30/35+ kms has been possible.
With SMS... My SMS's exceed voice distance., but may not go instantly.
I was recently working at King Ash Bay, NT and about 25kms from the Borroloola tower. Had good to fair signal with an external antenna. No normal mobile signal, but my Skype was crystal clear.
I also got good antenna assistance from Ken www.ldantennas.com.au/ Check out his Youtubes
Also look at Ken's
G Spot (The first minute shows it in use.)
http://www.broadbandantennas.com.au/index-mobile-broadband-antennas-homepage-nextg-telstra-optus-remote-phone-latest-online-info.html.html
It seems if your talking 'Bush', Telstra Broadband is the go.
I'm no expert and others may add better info. This is my personal experience only.
I'd like to hear how others get on with remote signal.
I also posted the above at www.myswag.org/forum/index.php?topic=7525.0