What Is 4GX?

In the next couple of months, you'll be hearing more and more about a new technology that Telstra is switching on around the nation at the start of 2015. 4GX is just a fancy name for the telco's new 700MHz mobile network frequency, but that's not the only thing you need to know about it.

Telstra is set to switch on its 700MHz frequency allocation on January 1, 2015 — that's the date that it is officially allowed to use the spectrum, as part of the agreement it made with the Federal Government when it purchased it at the Digital Dividend auctions. There are a few sites around the country, especially around inner-city Sydney, where pre-release trial sites are set up and already functioning, but for the most part the go-live date is January 1.

We first saw the name '4GX' on a Telstra Exchange blog post announcing the Sony Xperia Z3 and Xperia Z3 Compact (which, by the way, is a great phone).

It's Much Faster

Telstra's 700MHz allocation, which it purchased at auction (along with a significant chunk of 2500MHz) in May last year for $1.3 billion, is for two 20MHz segments of the frequency band — the majority of that frequency, and double the space of Optus's two 10MHz segments. It's in the APT700 band segment, which is becoming increasingly popular around the world — an important consideration for any telco considering adding new devices.

Being twice the bandwidth of Telstra's existing 1800MHz and 900MHz allocations, you can reasonably expect theoretical and practical download speeds to double, or even more, when you're using a 700MHz device. Telstra quotes 2Mbps to 75Mbps speeds for 4GX Category 4 devices — that's the LG G3s, Samsung Galaxy S5s, Sony Xperia Z3s and iPhone 6s that are already out in Australia. The 700MHz portion of the spectrum was previously used for analog TV signals, so it's good to see it going to very good use.

It Won't Work On All Phones

Not too many phones, tablets and 4G hotspots that have been launched in Australia support Telstra's 700MHz network, the frequency that is going to be called 4GX by the telco itself. That compatibility, for the most part, is restricted to more recent and more high-end handsets, and a few premium hotspots that Telstra sells exclusively. As time goes on, more devices are and will be released that support the new standard, but especially while it's new there won't be that many people using it.

That's a great thing for early adopters, who will enjoy massively improved speed — not only because of the 700MHz network's technical advantage over 900MHz and 1800MHz, but because there'll be fewer people contending for the same amount of bandwidth on any one mobile phone tower. As time goes on, speeds will level out to more reasonable and realistic rates, but when more handsets move to 700MHz it'll free up the other bands as well — everybody wins.

This is nowhere near a conclusive list, and it'll expand on a weekly basis as more devices are released, but here are most of the 700MHz, Telstra 4GX-capable devices you can buy in Australia as of today:

• Samsung Galaxy S5
• HTC One (M8)
• LG G3
• HTC Desire 610
• Samsung Galaxy Note 4
• Apple iPhone 6
• Apple iPhone 6 Plus
• Telstra Wi-Fi 4G Advanced Pro X (Netgear Aircard 782S)
• Telstra 4G My Pocket Ultimate Wi-Fi (Netgear Aircard 785S)
• Telstra 4G My Pocket Plus (Netgear Aircard 785S)
• Alcatel Pop S3
• Kogan Agora 4G

It's A Crucial Part Of Telstra's Next-Gen Network

The APT700 band — that's 4GX — forms one half of Telstra's fledgling LTE-Advanced Category 6 mobile data network, which will fuse together data channels from 700MHz and 1800MHz frequencies to further accelerate download speeds. In trials, Telstra has hit 450Mbps download rates on LTE-A, which is three times the theoretical limit of a single 4G band.

Telstra has also come out to say that wherever it deploys 700MHz, LTE-Advanced will be available. (That LTE-Advanced will also need an 1800MHz frequency band available and connected, too, for what it's worth.) So, if you're using one of two devices — the new Galaxy Note 4, or the Telstra Wi-Fi 4G Advanced Pro X (above) — you'll be able to hook up to LTE-Advanced and 700MHz alike as soon as it switches on.

You Might Already Be Using It

Telstra has 700MHz networks up and running, on a trial basis, and thanks to a bit of wheeling and dealing with ACMA and the government, in these locations already:

Surry Hills, Haymarket, Chippendale, Redfern, Waterloo, Zetland, Kensington, Alexandria, Erskineville, Eveleigh, Moore Park, Beaconsfield, Rushcutters Bay, Elizabeth Bay, Balmain East, Balmain, Birchgrove, Woolwich, McMahon's Point, Lavender Bay, Milsons Point, Kurraba Point, and Neutral Bay.

as well as:

parts of Sydney, Adelaide, Darwin, Sarina, Yamba and Bundaberg

with "20 more locations" being added before the end of the year. If you have one of the phones listed above, and you're in one of the areas listed here, then chances are you're using 700MHz already and not even realising. When it launches more widely — to 50 regional locations, and to cover a 3km radius around all of Australia's capital cities' CBD areas — it'll cover more customers again.

It's Not The Only Next-Gen Network

Optus bought a chunk of 700MHz too, and Optus is also planning its own 700MHz and LTE-Advanced network roll-out at the same time as Telstra is.

You don't necessarily need to use Telstra's 4GX to get yourself onto a next-gen 4G network; we'll leave you to decide which is best for your needs, which is the most technologically advanced, and which is the best value.