[mythtv-users] PVR950Q Finds 0 Services While a Regular TV Finds Clear Channels

[Michael Cracraft]

This may be more a DVB question than Myth, but I figured I would drop an
email to the list, and if someone knows a more appropriate list, I can send
my question there.

The cable company appears to be mucking around with the frequencies on the
clear QAM stations available over cable.  At first I thought that it was a
move to encrypt the basic cable stations, but that doesn't seem to be the
case.  Every regular TV with an HD tuner in the house picks the station up
after rescanning for channels.  However, I can't seem to detect any
stations now with the 950Q.

I am running Fedora 20 on my backend machine, and it is updated as of last
night to the present stable repositories.

First, I attempted to use Myth's channel scan in the input setup in
mythtv-setup.  I tried various settings with the full scan, but the
channels found did not match what I expected based on what showed up on my
TV.  I tried some of the other US frequency table options, IRC and HRC, but
those didn't turn up anything.  I don't think I tried QAM64, but previously
everything I used was on QAM256.

My second attempt was to use scandvb, .a.k.a scan or dvbscan depending on
the distro.  Every time I ran that with different US frequency tables, it
came back with 0 Services and no output.  I can clearly see the tuner
locking on to signals, but it doesn't return any channels to try.

I read about w_scan and thought I'd give it a try, but a couple jabs with
different switches returned the same 0 Services result.  Below is the last
command I tried with the first part of the output.

$ w_scan -fa -A2 -x -c US > dvbscan.txt

w_scan version 20130331 (compiled for DVB API 5.10)
using settings for UNITED STATES
ATSC
QAM US/CA
scan type TERRCABLE_ATSC, channellist 2
output format initial tuning data
WARNING: could not guess your codepage. Falling back to 'UTF-8'
output charset 'UTF-8', use -C <charset> to override
Info: using DVB adapter auto detection.
    /dev/dvb/adapter0/frontend0 -> TERRCABLE_ATSC "Auvitek AU8522 QAM/8VSB
Frontend": good :-)
Using TERRCABLE_ATSC frontend (adapter /dev/dvb/adapter0/frontend0)
-_-_-_-_ Getting frontend capabilities-_-_-_-_
Using DVB API 5.a
frontend 'Auvitek AU8522 QAM/8VSB Frontend' supports
INVERSION_AUTO
8VSB
QAM_64
QAM_256
FREQ (54.00MHz ... 858.00MHz)
-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
57000: QAM256(time: 00:03) (time: 00:04) signal ok:
    QAM256   f=57000 kHz
63000: QAM256(time: 00:04) (time: 00:05) signal ok:
    QAM256   f=63000 kHz
69000: QAM256(time: 00:05) (time: 00:06) signal ok:
    QAM256   f=69000 kHz
79000: QAM256(time: 00:06) (time: 00:08) signal ok:
    QAM256   f=79000 kHz
85000: QAM256(time: 00:08) (time: 00:09) signal ok:
    QAM256   f=85000 kHz

Has anyone else had a similar problem in the past where they could tune a
TV to the channel after a channel scan but couldn't find it on their QAM
tuner on Linux?

Thanks,
Michael
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