If you're looking at buying a new mobile device, especially one that's an import, it's worth knowing which Australian networks it will support. These are all the frequencies currently used in Australia.
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If you look beyond the fancy hype and words like "magical" and "revolutionary" in the description of any smartphone, you'll find tucked away somewhere the frequency bands that the phone itself works on. Here, for example, is the relatively simple list of bands that the iPhone 6/6 Plus supports. There are five different variants of the iPhone 6 alone, although the differences are relatively subtle. Across the Android fence, there are at least ten different variants of the Samsung Galaxy S5. Not all devices will work on Australian networks on precisely the same way, so it's well worth doing your homework if you're buying an overseas model, or indeed travelling to Australia with your existing overseas handset.
For any phone sold in Australia it should work seamlessly with the carrier it's intended for and you shouldn't need to fuss, but that's not much help if you're buying outright, especially if you use the growing number of sellers that offer import phones at lower price than the local RRP.
What you need to do is match up those frequencies with the frequencies that each major carrier uses to ensure that you'll have optimal coverage in the places where you're most likely to be.
As a side note, if all you're interested in is voice chat, all you need is a phone that offers 900MHz/1800MHz compatibility to cover the 2G networks of the major carriers for GSM. It has been a fairly long time since phones hit the market that didn't cover quad-band GSM (850/900/1800/1900Mhz) in the first place. For data, however, it's a little trickier, especially as some international handset variants offer either 3G or 4G compatibility that may work on some Australian networks, but not all.
Telstra's 3G and 4G networks operate across the most frequency bands of any major Australian carrier, with networks operating for 3G in the 850MHz and 2100Mhz bands and in the 4G space in 700MHz, 900MHz, 1800MHz and 2100MHz frequencies. Of those bands, however, you're most likely to be in spaces where the 700MHz, 900Mhz and 1800MHz bands predominate, with the other bands either being refarmed spectrum or trial sites. Telstra also has some spectrum holdings in the 2600MHz range, but to date it has only used that frequency for some high speed carrier aggregation testing, while suggesting it'll use it for global roaming arrangements as well.
What about 4GX?
4GX is Telstra's marketing name that encompasses a few different technologies when it comes to phone frequencies. Firstly, it's the marketing used to cover the 700Mhz network it started rolling out late last year, but also its use of LTE-A carrier aggregation technologies, which bond together the 700MHz and 1800MHz networks to offer significant theoretical boosts to download speeds.
Optus' 3G offerings operate at 900MHz and 2100MHz, but in the 4G space there are a few different bands to be aware of. Its 700MHz and 1800MHz 4G offerings use FDD (Frequency Division Duplex) in the same way as other carriers, and they're likely to be the most common networks your device will hit. It does have 2600MHz holdings with limited metro rollout, as well as a 2100MHz 4G LTE network in Darwin, Cairns, Hobart and the Sunshine Coast. Optus also has a TDD (Time Division Duplex) network at 2300MHz operating in Canberra only.
Vodafone's the only Australian carrier that didn't bid for the 700MHz frequencies opened up as part of the "digital dividend" auction back in 2013, with the result that it offers the smallest and simplest range of carrier frequencies of the major Australian carriers. It's the only carrier with 3G across three ranges (850MHz, 900MHz and 2100MHz), but in the 4G space it's currently only operating on the 850MHz and 2100Mhz frequencies, with plans to refarm much of its 3G 850MHz network capacity over to 4G by the end of 2014.
Like Telstra, Vodafone recently stated that it is going to introduce carrier aggregation in 2014, presumably across its 850 and 2100MHz bands, although the exact timeframe hasn't been stated for when that will become available. Carrier aggregation can offer significant downstream speed boosts as long as you can get enough signal in the first place, but it relies on you having an LTE-capable device that supports carrier aggregation in the first place.
Time to get the band back together
It's not just a question of frequencies, but also the band on which those frequencies operate relative to the device you're planning to use. Again, this should primarily be a focus if you're buying an overseas model device, as anything built for the Australian market should already take this into consideration.
It's precisely why, for example, Apple got in trouble a few years back relating to the "4G" on its iPad models at the time, because while they were "4G" compatible, it wasn't at a frequency and band rate that would work on Australian networks.
Thankfully, this is fairly simply regulated for the most widely spread networks in Australia, with 700MHz needing a band 28 compatible device, 850MHz on band 5, 1800Mhz using Band 3, 2100Mhz on Band 1, 2300Mhz on Band 40 and finally 2600MHz on band 7.
Hey, my telco's not listed!
Telstra, Optus and Vodafone operate the three major mobile networks in operation in Australia, but there are a number of mobile virtual network operators (MVNOs) who also operate. It's pretty simple to sort out their frequency requirements as a result, because the vast majority of operators resell Optus capacity in either 3G or limited 4G flavours. Telstra and Optus also have their own sub-brands -- Boost and Virgin Mobile respectively -- and again that's a matter of matching up your MVNO to its parent carrier to work out the suitable frequencies. Optus is the only carrier that has offered its 4G capacity in a wholesale basis to date, so those on a non-Optus MVNO need only look at 3G frequency bands.
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