Which is the best dth service for hd?

Is my Comcast HD cable service or T.V. glitching or do I need to (suddenly) purchase a service or device?

• I have an HD TV, and after plugging it in was able to receive HD basic cable (NBC, ABC, FOX, etc.) I purchased then (as well as now) basic cable, no additional HD service (which I know Comcast offers for about $6.50 in my region.) Today, the HD versions of those basic cable channels suddenly disappeared, about six months from when I purchased my TV. Now I'm curious: Is this just a glitch with Comcast; or my TV; or must I purchase HD service from Comcast; or a device? I've read that the HD service isn't necessary in order to view cable channels in HD, that one can pick up a converter box or some other device. However, then I don't understand why I was able to see HD channels without any special device. Please help? :)

• Answer:

  if the problem is with Comcast, then they will be very quickly restoring HD service. Comcast's service agreement with program producers, ie television networks, is that HD service will be provided to customers at no extra charge. so if they pulled the plug, it would only be temporary for equipment maintenance. i suspect the problem is with your television set. cable ready digital TV sets have two digital tuners, one is ATSC for off-air digital reception and the other is QAM for cable digital channels. either your TV did a reset and defaulted to the ATSC position, or you switched to ATSC in order to try and receive off-air television stations. switch the tuner back to QAM and your cable HD service should be restored.