The BBC has started test transmissions of terrestrial HD, using DVB-T2, an upgraded version of the standard DVB-T system used by Freeview. This new version of DVB apparently increases signal capacity by up to 30 per cent. Which for HD signals will come in very useful!

BBC R&D has built a prototype DVB-T2 receiver to pick up the new signals which won't work with any existing Freeview receivers. (nor any other DVB-T receivers)

Justin Mitchell, leader of the DVB-T2 modem development team at the BBC, said: "We are delighted that our team, in collaboration with our partners, has been able to deliver such a key piece of technology in such a short timescale.

"This is a big step forward in enabling the introduction of full HD terrestrial on Freeview by the end of 2009."

DVB-T2 as a standard was only finalised by the European DVB engineering group in March this year, but Ofcom and BBC hope to start broadcasts on Freeview by the end of 2009.

The test transmissions began on Friday, broadcasting from the Guildford transmitter southwest of London.

Some further points:

There are currently no commercial decoders that will decode the DVB-T2 signal.

The signal is being broadcast on UHF53 from the Guildford transmitter. a DVB-T tuner will see this signal, but will not be able to do anything with it.

More updates as we hear things...

Some further snippets of detail:

DVB-T2 should see a 30% increase in capacity of a DTT multiplex

After a re-org of channels and and an upgrade of multiplex-B this should allow room for FOUR HD channels on Freeview by 2012

If consumer receivers are available in time it is likely that Granada will be the first TV area to get HD channels on FreeView, towards the end of 2009.

DVB-T2 looks like it will carry 36 or 40 megabit per second signals

It looks like a demo demodulator will be on the DVB stand at IBC in Amsterdam in September.

The BBC are urging anyone able to make a receiver to give it a go.

Thanks to Lars for the pointers.