Well this is the big day for me... second phase of switchover, which means HD channels now available.
My main TV system is somewhat exotic to say the least, being based on the open source 'mythtv' project (
www.mythtv.org ). The tuners (three SD and one HD) all reside in a central Linux 'backend' server, then the two HD TVs (lounge & bedroom) get the signals over LAN, delivered by compact diskless 'frontend' boxes. If I ever found an excuse to install more HD TVs, the system can be extended to include them too.
Recorded programmes reside on the central server (the 'backend'), so they can be programmed in on either TV, and are available for watching on either TV. Similarly, other media (photos, music, videos) are instantly available in any room that has a myth frontend with TV.
With mythtv, each tuner can concurrently process up to 5 channels, providing they are all on the same multiplex. That means I can now, in theory, watch or record up to 5 HD channels and up to 15 SD channels concurrently. Disk access speed would probably present a practical limit to the number of channels being recorded, I've not yet explored where that limit would set in. But right now I'm recording 2 HD channels, while tuned to a third in the lounge and another upstairs, and all seems happy. There's only four available for now, anyway.
Feeling quite chuffed right now, the whole project has taken months to put together, it's nice to see it all working in full HD!
PS: @HP... if the need arose, I could add a satellite tuner or two to the backend as well, then satellite becomes available on all TVs. 8)