Why are there more HD channels in satellite versus?

If after the digital transition shouldn't ALL tv channels be HD then why do cable and satellite charge more for HD?

• Answer:

  I'll address the first of these two questions: Post-transition all US over-the-air broadcasts are digital. That refers to the modulation technique used to place a signal on a carrier wave. High Definition refers to the picture resolution, as does Standard Definition. A High Definition broadcast will always be digital, but a digital broadcast will not always be High Definition. A DVD will deliver a digital picture in SD. A Blu-Ray DVD delivers a digital picture in HD. The same concept applies to broadcasters. The FCC requires digital broadcasts, but does not require that they be HD. The cable provider I use does not charge for HD channels.