I just got a PVR-500MCE which turned out to have the Samsung tuner for which
support was just added.
I discovered over the past two days that all of my History Channel recordings on
US cable channel 55 were borked. I looked on the list, and noticed that a lot
of people were having problems with US Cable channel 55, and US Cable channels
7 and 19-22. I managed to confirm that US Cable channels 7 and 19-22 were also
not functioning properly for me.
I dug through tuner.c and a US cable frequency table
(http://www.jneuhaus.com/fccindex/cablech.html), and discovered the following:
Channel 55 at 409.25 is approx 1 MHz below the 0.4.2 driver's upper band switch
threshold of 410.25 MHz.
Channels 19-22 and 7 consist of all channels between 145.25 MHz (Channel 18) and
the driver's lower band switch threshold of 175.25.
Changing the thresholds to 146.75 and 404.25 respectively has fixed all problems
I had with the aforementioned channels. (See attached patch) It seems that the
thresholds in the 0.4.2 release were wrong (in the case of the lower threshold,
off by nearly 30 MHz). The above two thresholds work much better, and will
probably work perfectly for anyone on a standard US Cable channel table. They
MAY cause problems with people on other channel tables who have a channel
carrier frequency close to those thresholds, as they are not exact. They were
merely chosen to occur between the highest frequency working channel and the
lowst frequency nonworking channel for each band switch.
Also, someone made a post to the list indicating problems with fuzzy channels on
the VHF lowband - I suggest rebooting. It seems that fiddling around a lot with
the drivers (i.e. trying to get it to work initially) can potentially put the
tuner into a wonky state that can't be fixed by simple module reloading. I had
the same problem on my system initially but haven't seen it at all since a
reboot.
diff -ur ivtv-0.4.2/driver/tuner.c ivtv-0.4.2-newtuner/driver/tuner.c
--- ivtv-0.4.2/driver/tuner.c 2006-01-12 13:29:42.000000000 -0500
+++ ivtv-0.4.2-newtuner/driver/tuner.c 2006-01-26 18:20:54.000000000 -0500
@@ -333,7 +333,7 @@
{ "Philips TD1316 Hybrid Tuner", Philips, PAL,
16*160.00,16*442.00,0xa1,0xa2,0xa4,0xc8,623 },
{ "Samsung TCPN 2121P30A", Samsung, NTSC,
- 16 * 175.75, 16 * 410.25, 0x01, 0x02, 0x08, 0xce, 732},
+ 16 * 146.75, 16 * 404.25, 0x01, 0x02, 0x08, 0xce, 732},
};
#define TUNERS ARRAY_SIZE(tuners)
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