[mythtv-users] Cablecos and QAM
Gary Buhrmaster
gary.buhrmaster at gmail.com
Wed Nov 20 21:00:25 UTC 2013
On Wed, Nov 20, 2013 at 8:22 PM, Jay Ashworth <jra at baylink.com> wrote:
....
> But there are still lots of tuners to which I could move that support
> clear-QAM, but *don't* support Cablecard, and it's that decision I'm
> trying to decide how to make.
Absolutely, there are a lot of clear QAM tuners. The advantage of
CableCARD tuners is mostly in the care and feeding of the system.
MSOs will occasionally shift the frequency/programid around,
which (on a real TV) requires a rescan. In MythTV you have to
also do the equivalent (on some MSOs, that can be automated,
on others, not so much; AFAIK Comcast (no longer relevant)
and SuddenLink made it programmable by including the data
in-band). OCUR tuners eliminate that problem (the map is
processed by the CableCARD), making the system easier to
support. Clear QAM tuners will sometimes also be able to
record more content at once using virtual tuners, if your MSO
happens to map more than one interesting channel to the same
frequency (which, for my particular MSO, happens almost never).
On the other hand, one could probably purchase two or
three clear QAM tuners for the price of an OCUR tuner
(ignoring the fact that SiliconDust is running a "clear out
the old" sale on their Prime unit. Woot and Newegg had
the units for ~$100 each).
Personally, I used clear QAM tuners for a few years, and
was generally happy. The only problems I encountered
resulting in lost recordings were (a) POS power bricks
(that I replaced en-mass), and (b) Comcast deciding that
today was a good day to change the mapping (and my
crontab to update the mapping either had not yet run,
or failed due to loss of signal on the in-band frequency,
which they also changed from time to time), or (c) the
channel mapping was (somehow) incomplete, so some
subset of the channels stopped working If Comcast
had not encrypted the extended cable channels, I would
likely still be using the clear QAM tuners, but I was also
willing to deal with the PITA daily review to make sure
nothing bad was happening, and I had the attitude of
"it is only TV", so if I lost a show, well, it is not the end
of the world.
Gary
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