Established for around 10 years, DVB-S has been the de facto modulation standard for broadcasting digitally by satellite. Technology has moved on, DVB-S has now been eclipsed by a more efficient variant known as DVB-S2. It should come as no shock to learn that DVB-S-compliant products are incompatible with the new breed of DVB-S2 services.

Currently, these tend to be HD channels using the cutting-edge H.264 video codec rather than the MPEG-2 traditionally associated with DVB-S. They include a handful of free-to-air channels and pay-TV packages on Astra 1 (19.2°E) and Hot Bird (13°E).

Among them are Astra's unencrypted HD 'barker' channel, ProSieben HD, Anixe HD, LuxeTV and the pay-TV service HD1/Euro1080. SkyHD, carried via Astra 2, has also plumped for DVB-S2, and the PVR sold by Sky for its service has a pair of tuners able to receive both DVB-S ('legacy' standard-def Sky Digital) and DVB-S2 (SkyHD) services.

Interestingly, the free-to-air BBC-HD trial channel that SkyHD subscribers enjoy as an added bonus combines DVB-S modulation with H.264 and can thus be received with a PC equipped with a standard tuner card and H.264 software codecs.

Decoding H.264 in real-time at hi-def resolutions (1280 x 720 or 1920 x 1080) is a punishing task for PCs. You'll need a very fast PC - 3.2GHz Pentium 4 or equivalent - equipped with a powerful graphics card.

Although the reception of BBC HD outside the DTT trial area without a need for a Sky subscription may be an excuse to upgrade that PC to a meatier model, the extra channels available elsewhere on the Clarke Belt wouldn't go amiss. In any case there's no guarantee that the Beeb won't switch to DVB-S2 in the near future - assuming that it's allowed to continue.

DVB-S2 tuners for PCs were first hinted at last year, but the Far East-sourced product in question only surfaced in Germany - the first European country to switch to HD satellite in a big way. Funnily enough, German company Technisat is offering the UK its first DVB-S2 card.

The card in question is made for Technisat by Technotrend, and - like the SkyHD and Pace DS810 boxes - is also compatible with standard DVB-S services. In other words, the same card will receive both standard and high-definition channels.