recording Comcast digital channels with MythTV

[James R. Van Zandt]

For several years, I've been running MythTV with a Hauppauge PVR-500
dual analog tuner.  However, Comcast has been moving channels from
analog to digital, and they've just sent a letter announcing more will
be moving next March.  So I'm in the market for a digital tuner.

I ran across the Hauppauge HVR-2250 at New Egg:
  http://www.newegg.com/Product/Product.aspx?Item=N82E16815116037
  http://www.newegg.com/Product/Product.aspx?Item=N82E16815116036
  http://www.hauppauge.com/site/products/data_hvr2250.html
  http://www.mythtv.org/wiki/Hauppauge_HVR-2250

Looks great: a dual tuner with only one cable input, handles analog or
digital signals.  As it happens, it was also mentioned in today's
Boston Globe (page G2).

There's a Linux driver: http://www.kernellabs.com/blog/?page_id=17

Unfortunately, it only handles digital so far.  So I guess I'd need
to keep the PVR-500 after all, and another splitter.

However, I think this will only handle the clear QAM signals.  How
many channels does Comcast encrypt?  

For our regular TV (separate from the MythTV setup), we have a cable
box (Motorola model DCT700/US) which I assume decrypts and converts
from digital to analog.  To record encrypted channels, I guess I could
connect my current analog tuner downstream of the cable box.

But I think that would only give me one channel at a time, and
necessitates double conversion (digital->analog->digital->analog).

What's a better solution?  E.g. another kind of set-top box that just
decrypts?  More than one channel?

Are there DRM issues with the HVR-2250?

Can anyone point to a technical description of the Comcast channel
lineup (analog, digital, HD, clear QAM, encrypted, ...) for the Nashua
area?

For example: for each analog channel, does Comcast transmit a digital
version too?

         - Jim Van Zandt