[mythtv-users] HDHomeRun Prime does _NOT_ do US OTA, what does?

[Joseph Fry]

>>> A week or three ago, I asked for suggestions for a network-based
>>> TV tuner for US ATSC over-the-air.  Sadly, the HDHomeRun Prime
>>> is incapable of tuning US over-the-air channels and is cable-only.
>>
>> I'm sorry for being one of the people who gave you bad advice.
>
>
> Technically, you didn't.  You told Stephen Villano to get a Prime:
>
> http://www.gossamer-threads.com/lists/mythtv/users/550944#550944
>
> In truth, no one actually suggested the Prime to Robert because
>
>
>> In your original message, I don't think you included the phrase
>> "over-the-air" explicitly.
>
>
> he only said "ATSC" in his post.  Since ATSC is the digital TV format used
> for both OTA and cable TV delivery in the US***, there wasn't enough
> information to determine which one Robert needed.  Both were mentioned as
> being networked tuners, but no one specifically warned him that the Prime is
> CableCARD only.  I suppose most assumed that a pre-emptive warning was
> unnecessary as the product documentation described the compatibility.
>
> That said, Robert, I completely understand how easily you could have been
> confused.  Unfortunately, using MythTV (and the related hardware products
> that allow it to work) requires a significant level of understanding of
> TV-related technologies due to the fact that we're constantly "swimming
> upstream" against the current of lock-in that TV providers attempt to
> emplace.  They want us to just use (and pay for) their equipment so they can
> control how we use their service, so they make it challenging to find out
> what equipment we need and/or what will work with their systems.
>
> So, the best bet at this point is to move on with new knowledge in hand.
> You can sell the Prime you bought.  I also recommend you don't blame Silicon
> Dust, and you enjoy their HDHR (non-Prime), which is really the only choice
> of networked OTA ATSC tuner available for use with MythTV.  It's a great
> product and Silicon Dust is a great company that--from their start--has
> supported GNU/Linux users completely.  (At least that's my $0.02.)
>
> Mike
>
> *** Yes.  ATSC /is/ used for both OTA and cable TV delivery in the US.
> Though many say, "Cable uses QAM, and OTA uses ATSC," the fact is that cable
> TV delivers ATSC using QAM (Quadrature Amplitude Modulation) and OTA
> delivers ATSC using 8VSB (8-level Vestigial SideBand) modulation.  (However,
> ATSC is not generally used for satellite TV transmission--and, AIUI, not at
> all for consumer satellite TV services, like DISH and DirecTV, but only for
> a few direct network feeds.)

Clarification.

OTA does use ATSC, 100% of the technology is defined by the ATSC
standards body.  When you say ATSC, your actually talking about a
standards body with hundreds of standards defining everything from
encoding to deinterlacing... just like ANSI, ISO, etc.

"ANSI/SCTE 07 2006: Digital Transmission Standard For Cable
Television" is the standard that defines QAM, as you can see it is an
ANSI standard rather than an ATSC standard.

This is why an ATSC tuner does not necessarily need to support QAM,
though most do.  ATSC does define a standard for cable carriers
(16VSB), however few actually adopted it; and went with QAM-256
instead.

It is expected that the ATSC will adopt QAM-256 into the standard
sometime in the future, however it hasn't done so yet.  This is why a
tuner must specify ATSC and QAM if it has QAM tuning capability; once
QAM-256 is adopted into the ATSC, an ATSC tuner would need to be able
to tune QAM-256 to be standards compliant.

That said, the television data carried on a cable systems QAM carrier
usually conforms to the ATSC standards for bitrate, resolution, etc as
that is the standard that most televisions are certified to support.
However QAM carries a lot of other information (internet, STB guide
data, etc) that is not necessarily in an ATSC standard format.

Oh, and in many cases, Satellite TV services do use some ATSC
standards, such as the resolutions, interlacing, and who knows what
else defined in the ATSC... really not much different than QAM.
Satellite TV could have chosen to broadcast at some random resolution,
but because most televisions are ATSC compliant, it made more sense to
adopt those standards to ensure that customers got the best picture
possible.