It called a press conference with two hours’ notice this morning to announce plans to significantly boost its 4G network coverage.

Vodafone Hutchison Australia (VHA) says that nearly one third (1.5 million) of its nearly 5 million customers are now on 4G, a number it wants to increase significantly be the end of the year.

The network expansion will largely use Vodafone’s low-band 850 MHz spectrum holding. The company says that the re-allocation of this spectrum, known as ‘re-farming’, means its 4G coverage will reach 95% of Australia’s metropolitan population by the end of 2014.

Note the use of the word ‘metropolitan’ – that means Australia’s larger cities. The greater coverage will make Vodafone’s 4G network competitive in those cities, but it will be far behind in the bush, where it is relying on its greatly improved 3G network.

Vodafone is also relying on the fact that most existing phones can use the new spectrum. “Vodafone 4G customers will immediately benefit from the switchover without having to make any changes to their handsets, settings or plans,” said CTO Benoit Hanssen, announcing the plans. “The majority of available 4G smartphones and tablets are designed to work on the 850MHz spectrum.”

Hanssen says that by comparison there are currently only a few smartphones handsets that can be used on the 700 MHz band, which was freed up from analogue TV and acquired by Telstra and Optus in last year’s ‘digital dividend’ spectrum auctions, in which Vodafone did not participate.

The digital dividend 700 MHz spectrum will become available from the end of the year, but Hanssen points out it will need new handsets.

“Australian smartphone customers already have handsets that will work on Vodafone’s low-band 4G 850 MHz network. But very few of the smartphones sold in Australia since the introduction of 4G support the APT 700 MHz spectrum. Telstra and Optus customers will therefore require a new device in order to experience low-band 4G services,” said Hanssen.

He said low-band spectrum, such as the 850 MHz, is particularly suited to providing high-quality indoor mobile coverage. “Re-farming creates a 4G coverage layer that complements Vodafone’s existing high-band 4G network, which uses the 1800MHz spectrum band.”

Australia’s three main carriers have been involved in a long running war of words over whose network offers the most coverage, and which is fastest. Telstra in particular has been protective of its turf, taking Optus to court over the extent of its claimed geographic coverage, and threatening to do the same to Vodafone over its speed claims. Vodafone now simply says it offers ‘superfast’ data speeds in Sydney and Melbourne, where it currently has more bandwidth than Optus or Telstra.

Telstra is relying on its greater coverage across Australia, which enables it to charge a premium. Optus has extensive coverage and is using its unique use of TDD (time division multiplexing) to boost data speeds, and Vodafone is relying on the unique characteristics of its spectrum holding to claim an advantage. It is also cheaper than its rivals.

Hanssen said Vodafone has completed a successful trial of 850 MHz 4G in Newcastle, during which it tested a wide range of 4G-compatible devices at more than 40 sites. He said the beauty of re-farming its 850 MHz spectrum for 4G is that the company already owns the spectrum.

“I am pleased we’re able to use the flexibility of our new network to provide our customers with an even better 4G experience.” He said. “This provides Vodafone the platform for the next stage of our network evolution.”

Hanssen said Vodafone’s overall network was performing very well following billions of dollars in investment over the past three years. The company lost more than two million customers after its ‘Vodafail’ network meltdown of 2011.

Since then Vodafone has undertaken a complete rebuild of its 3G network, and launched 3G+ and 4G networks. Customer numbers are still dropping, but they are close to stabilising. It has had to rebuilding its reputation, never an easy process.

“It’s getting harder for our competitors to justify charging more,” said Hanssen, in an obvious dig at Telstra. “Our customers are enjoying our new network and those who have recently joined us are impressed how far we’ve come.”

That may be true, but there is still a way to go.