Motorola SurfBoard DOCSIS 3.0 Cable Modem

I was one of the first to get a Motorola SB6120 -- and was very much satisfied with the ease of set-up, the awesome speeds, the functionality, and the workmanship. But, like all electronic gizmos, they tend to crap out after a few years. When my SB6120 started dropping upstream channels, I looked to Motorola once again -- right here at Amazon -- and found the new Motorola SB6121. After checking the specs, I found that the new SB6121 Model has the latest IPV6 technology (higher bandwidth capabilities)that were not available on the SB6120. The newer IPv6 technology allows connection speeds up to 160 Mbps., against the 150 Mbps of the SB6120. IPV6 is not in common usage yet, but it will be pretty soon -- And the SB6121 will be ready with the fastest speeds available!! The new SB6121 is a super-easy set-up, and the connection speeds are fast and steady. Comparing the DOCSIS 3 SB6120 to the newer SB6121 : 1.- The Sb6121 is smaller (height and depth are smaller, width is greater). 2.- The SB6121 runs slightly (average about 5 degrees F) warmer than the SB6120. 3.- Connection speeds, latency, and jitter are better with the SB6121 than the SB6120 -- and WAY faster than ANY DOCSIS 2 modems, regardless of manufacturer. Some tips I learned from using the Motorola DOCSIS 3 Modems with 2 different (D-Link DIR-655 and Netgear WNR3500L) "N"-speed Wireless Routers: The SB6120 runs coolest when mounted to a wall or other vertical surface, and spaced approximately 1/2-inch away from the surface. This allows an adequate air flow that's necessary to keep the Modem cool. Mounted with the wires pointing straight down, the SB6120 runs at about 95 degrees F in a 78 degree room when mounted away from a wall. Temperatures measured with Mastercool Infra-Red Laser Thermocouple Gun (available at Amazon). The new SB6121 is smaller than the SB 6120, and it runs a little bit warmer (98-100 F), even when mounted the same way as the SB6120. I suggest that you mount the new SB6121 1/2" away from the wall as well, but with the wires pointing straight back. Whatever you do, DON'T STACK ANYTHING on ANY Modem or Router !! Both of these devices give off heat and electrical interference, and will perform their best when spaced about 4 feet apart, which keeps the interferences from overlapping and killing the Wireless Router's range. When you get your internet connection going, go to the Motorola Modem's Home Page: Sample snapshot of my SB6121 = Cable Modem Status Signal Addresses Configuration Logs Open Source Help This page provides information about the current upstream and downstream signal status of your Cable Modem. -------------------------------------------------------------------------------- Downstream Bonding Channel Value Channel ID 49 50 57 58 Frequency 837000000 Hz 843000000 Hz 861000000 Hz 867000000 Hz Signal to Noise Ratio 37 dB 37 dB 38 dB 38 dB Downstream Modulation QAM256 QAM256 QAM256 QAM256 Power LevelThe Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading -1 dBmV -1 dBmV -1 dBmV -1 dBmV Upstream Bonding Channel Value Channel ID 3 1 2 Frequency 36100000 Hz 23300000 Hz 29600000 Hz Ranging Service ID 7425 7425 7425 Symbol Rate 5.120 Msym/sec 2.560 Msym/sec 5.120 Msym/sec Power Level 45 dBmV 45 dBmV 45 dBmV Upstream Modulation [3] QPSK [3] 64QAM [3] QPSK [2] 16QAM [3] 64QAM [3] QPSK [3] 64QAM Ranging Status Success Success Success Signal Stats (Codewords) Bonding Channel Value Channel ID 49 50 57 58 Total Unerrored Codewords 1457238562 1457238645 1457237949 1457238150 Total Correctable Codewords 17 26 23 27 Total Uncorrectable Codewords 1031 937 1682 1468 -------------------------------------------------------------------------------- Status | Signal | Addresses | Configuration | Logs | Open Source | Help © Copyright 1997-2008 It should give a snapshot of the specs for YOUR modem. You will be looking for 4 Downstream channels that read SNR @ 37-38 db and the power levels at around 0 dbmV. Upstream power levels on all 3 bonding channels should read around 45-50 dbmV. A deviation of 5 from any of these figures indicates a problem. If the Modem's signal is solid and constant, but the power level readings are 5 points off in either direction, check your OUTDOOR SPLITTERS or TAPS first, because they tend to crap out when they're exposed to heat for long periods. The operating temperatures for splitters and taps is only 140 degrees F. maximum, and that temperature is easily reached in direct sunlight, even when enclosed. Those of you who live in hot climates may notice that the Modem's downstream power levels drop off 1 or 2 points when the outside temps get up to 110 F or higher. Don't panic !! In case of rapture, dial 1-800-Oh Jesus. ;>) I found the RCA DH24SP High-Bandwidth (5-2400MHz)2-Way Signal Splitter (available at Amazon) to be an excellent handler of the high-speed signals of Cable, Satellite, and HDTV signals. It's a "2-Way" splitter, so the power flows equally in either direction, enabling MUCH higher upload speeds. If you need a TAP for unequal cable lengths, a CommScope SV-DC-6G Digital Tap worked well for me. For strong and clear Wireless range and reception, use only Category 7 (shielded) Ethernet cable (available at Amazon) between your Modem and Router, and between your Router and Main computer. Good Luck !!