[mythtv-users] Time Warner: MythTV channel scan differs from Silicon Dust listings

Brian Wood beww at beww.org
Thu Dec 2 22:27:21 UTC 2010

On Thursday, December 02, 2010 03:14:40 pm Eric Sharkey wrote:
> On Thu, Dec 2, 2010 at 1:35 PM, Dan Wilga
> <mythtv-users2 at dwilga-linux1.amherst.edu> wrote:
> > On 12/2/10 1:25 PM, Steven Adeff wrote:
> >> I'm setting up a house-wide MythTV system for my parents. I've got
> >> the backend set up and built, it's QAM tuner is connected to the
> >> cable line and I've run a channel scan but the freqid's found
> >> don't completely correspond to the listings shown on the silicon
> >> dust site,
> >> http://www.silicondust.com/hdhomerun/lineup_web/US:90045#sidebysi
> >> de
> >> 
> >> is this more likely due to silicon dusts listing being out of date
> >> or a channel scan issue within Myth?
> > 
> > It could be either. The listings on SD's site work by receiving
> > data from the HDHR's of individual users. The data and screen
> > shots are sent during periods of inactivity on the HDHR.
> > 
> > Because of this, the listings are dependent upon someone in your
> > area having a HDHR hooked to the same provider as you. If they
> > aren't using the exact same provider, or if they subscribe to
> > different channels, the listing will be out of whack. If they stop
> > using the HDHR, the listings won't get updated.
> I've never gotten a scan that exactly matched the Silicon Dust
> listings on the web.  It's usually close, but there's always
> something in a different spot or another channel here or a missing
> channel there.
> It's not just that the listings are out of date, because they do
> change frequently and you can sometimes tell from the screen shots
> approximately when the data was collected, and they're usually in the
> very recent history, but it's my suspicion that geographic regional
> differences in channel tables don't match precisely with zip code
> boundaries.

They are dependent on what headend is feeding the particular customer, 
which is based on distribution system design, not zip codes.

Sometimes franchise agreements stipulate that certain channels be 
carried in the "lower 12", or other specified place, or that community 
access channels be in certain places etc., so franchise area might be a 
better guide than zip code.

> Up to date and accurate channel frequency tables is something I wish
> Schedules Direct was able to supply.

It would be nice, but would cost time and effort, I certainly would not 
want to detract from their prime mission, though I would be happy to pay 
a little extra for such information (not sure if I'm in the minority 
here though).

Maybe we could get Google to slap a spectrum analyzer on a few cable 
drops as they run around getting street-level views and grabbing WiFi 

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