It's the most commonly asked question whenever we write a story about 4G — if I buy one, where else will will my 4G phone work? At the time of writing, if you're after an Aussie 4G phone, your choices are limited by both network and handset. There's one 4G LTE carrier — Telstra* — and one handset — the HTC Velocity 4G. We've seen what it's like. We've tested it against other 3G phones. But where does it work for 4G coverage?
If you're after Australian coverage, Telstra's coverage map should give you a rough indication of where you can get 4G coverage. Bear in mind that radio waves are temperamental little sods, so just because the map says it's covered doesn't automatically make it so.
What about international coverage? Telstra's answer on this is pretty definite; it doesn't have any international 4G roaming arrangements available right now, but then, given the wide variety of services sold internationally under the banner of "4G" — something we've complained about previously — that's hardly surprising.
What you should be able to do with the Velocity 4G is roam onto 3G HSPA+ networks where Telstra does have a roaming arrangement. That's not going to give you 4G speed, and there are plenty of horror stories of international roaming gone awry, especially given the high price of roaming charges, but it's a start.
What about international visitors with 4G-capable phones? The story is, if anything, worse in reverse. The same variety of "4G" labels that get put on differing 4G phones and devices means that there's no guarantee that your device will connect to anything at all on Aussie shores; you'll have to check with your carrier about roaming arrangements and check the exact specifications of your device prior to travelling.
*Yes, I know Unwired exists, and that it touts its WiMAX solution as 4G. They don't sell phones, OK?