How do I enable QAM support without using the DVB drivers?
There is backport of QAM support into the pcHDTV's video4linux drivers. See this post for more information.
How do I scan for QAM channels?
pcHDTV 3000 supports unencrypted QAM channels over cable. You must have the DVB module drivers (cx88_dvb) loaded to use QAM. [TODO add link to pcHDTV forums on DVB driver installation.] To scan for QAM channels:
1. Get the dvb-apps tools from cvs.cvs -d :pserver:firstname.lastname@example.org:/cvs/linuxtv login cvs -d :pserver:email@example.com:/cvs/linuxtv co dvb-apps
2. Read the dvbs-apps/INSTALL to compile and install.
3. Save this channel.conf to ~/.azap/channels.conf.
You should be able to scan for QAM channels using azap (part of the dvb-apps tools). Run 'azap [channel]' to scan for a specific channel. For example:$ /usr/local/bin/azap c88 using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0' tuning to 609000000 Hz video pid 0x0000, audio pid 0x0000 status 1f | signal f3f6 | snr fd27 | ber 00000000 | unc 00000000 | FE_HAS_LOCK status 1f | signal ef9c | snr fd2b | ber 00000000 | unc 00000000 | FE_HAS_LOCK status 1f | signal f3f6 | snr fd29 | ber 00000000 | unc 00000000 | FE_HAS_LOCK
The FE_HAS_LOCK indicates a signal lock on channel c88. Cable channels typically begin at c80.
You can also use MythTV 0.17 to automagically scan for channels on your DVB card. Make sure you compile it with DVB support. MythTV 0.17 only enables QAM-256. See this thread for a patch that enables QAM-64.
How do I know if a QAM channel is encrypted?
There does not seem to be a direct way to tell for certain. See this post and this reply (March, 2005). There is, however, an indirect way to find out which channels are encrypted. Visit the Local HDTV Info and Reception on AVS Forum. Find the thread topic that corresponds to your local area. You should be able to find quite a bit of discussion from people with QAM tuners in their TVs or separate tuners like the Samsung SIR-T4151 which will indicate if your local channels are in clear QAM or not.
How do I record a stream from DVB?