Originally Posted by ybsane
Not sure what areas of the country have what gear, with the spacing of the upstream you have listed there, it is just 16QAM. 64QAM requires 6.2mhz spacing.
This person Brady Volpe and John Downey at Cisco are incredible when it comes to Doscsis information. I have seen them at SCTE events twice and spoke to both of them in great detail about downstream and upstream bonding.
surprisingly QAM64 can be used on a 3.2MHz channel and it only has a payload 15Mbps over the 9Mbps a QAM16 channel has. I know when I had a SB6120 it showed both QAM16 and QAM64 on the upstream so the channels have both so if you get noise the channel can fall back to QAM16. Also it allows the modem to keep bonding the channels instead of losing an upstream.
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 1 783000000 Hz -4.1 dBmV 37.4 dB 107 0
2 Locked QAM256 2 789000000 Hz -4.4 dBmV 37.4 dB 143 0
3 Locked QAM256 3 795000000 Hz -4.9 dBmV 36.4 dB 381 0
4 Locked QAM256 4 801000000 Hz -5.1 dBmV 36.7 dB 479 0
5 Locked QAM256 5 807000000 Hz -5.9 dBmV 35.5 dB 1614 0
6 Locked QAM256 6 813000000 Hz -5.7 dBmV 36.8 dB 1043 0
7 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0
8 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked TDMA and ATDMA 10 2560 Ksym/sec 33000000 Hz 42.2 dBmV
2 Locked TDMA and ATDMA 9 2560 Ksym/sec 36500000 Hz 42.2 dBmV
3 Locked TDMA and ATDMA 11 2560 Ksym/sec 29500000 Hz 42.2 dBmV
4 Locked TDMA and ATDMA 12 2560 Ksym/sec 24500000 Hz 42.2 dBmV
this is what modem channels look like. I would assume that something similar would be coming to Charlotte soon but instead of the channels being in the 780MHz-816MHz range it would be in the 500MHz-750MHz due to Charlotte being a 750MHz system. Ybsane Doesn't Charlotte push out to 120 (771MHz) I know some TWC systems go out to 122 (783MHz) which is pushing it for 750MHz gear. I know the Mooresville/huntersville areas that are served by TWC use channels up to I think 127 (813MHz) with SDV QAMs at the top end.