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 !!
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Climate Pledge FriendlyProducts with trusted sustainability certification(s). Learn morePRODUCT CERTIFICATION (1)
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Climate Pledge FriendlyProducts with trusted sustainability certification(s). Learn morePRODUCT CERTIFICATION (1)
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Compare with similar items
This Item  Motorola SURFboard SB6121 Cable Modem (SB6121) |  |  |  |  |  | |
| Price | -25% $59.99 Typical: $79.95 | -12% $149.99 New Price: $169.99 | -46% $34.95 New Price: $64.99 | $99.99 | -11% $196.45 List: $219.99 | $42.05 |
| Delivery | Get it Aug 1 - 5 | Get it as soon as Tuesday, Jul 30 | Get it Jul 31 - Aug 2 | Get it as soon as Tuesday, Jul 30 | — | Get it Jul 30 - Aug 1 |
| Customer Ratings | ||||||
| Easy to install | ||||||
| WiFi signal | ||||||
| Tech Support | ||||||
| Value for money | ||||||
| Sold By | GFLOnline | Motorola Networking Renewed | Search Buy Repeat | Hitron Americas | Fba Sales | eTechtronics (Your Trusted Online Retailer) |
| connectivity tech | Wired | Ethernet | Ethernet | Ethernet | Ethernet | Ethernet |
| ethernet ports | — | 1 | 1 | 2 | 2 | 1 |
| number of ports | 4 | 1 | 1 | 2 | 2 | 1 |
| data transfer rate | 160 megabits per second | 3.8 gigabits per second | — | 1 gigabits per second | 2500 megabits per second | 800 megabits per second |
| max downstream rate | 172 megabits per second | — | 960 megabits per second | 1000 megabits per second | 2500 megabits per second | 800 megabits per second |
| max upstream rate | 132 megabits per second | 3.8 gigabits per second | 960 megabits per second | 350 megabits per second | 2.5 gigabits per second | 262 megabits per second |
| modem type | cable | cable | cable | cable | cable | cable |
From the manufacturer
ARRIS SURFboard
Since 1997, when the first SURFboard was launched in Retail, SURFboard modems have been amongst the leading modems in the market and saving consumers money on their monthly rental fees.
When you choose an ARRIS SURFboard, you’re joining a 60-year legacy of innovation from the company that invented digital TV and brought wireless Internet into the home with the first cable modem gateway. The same company that the world’s leading service providers choose to connect millions of people around the world to the Internet.
Harness the power of SURFboard and take control of your home network!
SURF with the original and save money!
A lightning-fast Internet experience like no other. The SURFboard SBG6700-AC is 3 products in 1: a DOCSIS 3.0 Cable Modem, Dual-Band Concurrent 802.11ac Wi-Fi Access Point and 2-Port Gigabit Ethernet Router. With download speeds up to 343 Mbps and Wi-Fi speeds up to 1600 Mbps your gaming and video streaming just got better! Beamforming technology provides maximum Wi-Fi coverage and performance. Stop paying rental fees. Own yours today!
Amazing Features
- DOCSIS 3.0 Cable Modem
- Download speeds up to 343 Mbps
- 8 download & 4 upload channels
- 2 – Gigabit Ethernet Ports – 10/100/1000 Mbps
- 2.4/5.0 Ghz Dual-band concurrent
- 802.11ac W-Fi speeds up to 1600 Mbps
- Supports IPv4 and IPv6 – the latest Internet standard
- Wi-Fi beamforming – max coverage & performance
- Compatible with major U.S. Cable Providers
|
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|---|---|---|---|
| SBG6580 Wi-Fi Modem | SBG6700-AC Wi-Fi Modem | SBG6900-AC Wi-Fi Modem | |
| Customer Reviews |
6,267
|
1,650
|
1,470
|
| Price | $118.00 | $38.95 | $59.99 |
| Download Speed | 343 Mbps | 343 Mbps | 686 Mbps |
| DOCSIS | 3.0 | 3.0 | 3.0 |
| Gigabit Ethernet Ports | 4 | 2 | 4 |
| Wi-Fi | N300 dual-switched | AC1600 dual-band concurrent | AC1900 dual-band concurrent |
| Pre-set Wi-Fi Security | ✓ | ✓ | ✓ |
| Wireless Guest Access | ✓ | ✓ | ✓ |
| Energy Efficient Ethernet | ✓ | ✓ | ✓ |
| 2 Year Limited Warranty | ✓ | ✓ | ✓ |
| Tech Support by ARRIS | ✓ | ✓ | ✓ |
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COMPARING Surfboard Cable Internet Modems #thisorthat
Sarah Morgan
Reviews with images
This is the sweet spot in current modems.
After researching for a while I managed to finally find a modem that does exactly what I needed it to do. Just an fyi, per Comcast, "Special Note on this Device, Only purchased SB6121 retail devices will continue to be activated on our network. The Comcast leased version of this device will no longer be activated." What all that means is that as long as you buy this on your own you can still use it with them. Which makes sense cause if you keep renting from them you will end up paying $10 per month for as long as you own it, or $120 a year. I bought mine Used in Very Good Shape for about $35 which is a steal vs $70 new, still good. So basically, the perks of having this modem are that it meets Docsis 3.0 which is what Comcast requires, it goes up to 172 Mbps which is pretty high, and with your own modem without built in wireless gateway you get to buy your own router that supports the speed and range you need. Now you might think the SB6141 is a better buy, and it's not bad, just more money and a higher data speed cap of 343 Mbps, which isn't bad but it's very expensive to pay for those kinds of speeds from Comcast. Realistically most people myself included can get by on just 25 Mbps. Now think about it this way, this modem can support 172, and I pay for 25 at $40 a month yet get 30 Mbps. So why pay for more in Modem if you aren't going to get that speed from your provider. We use on average about 750GB's per month too. 1 smart tv, 2 smart phones, 1 tablet, 1 desktop, 1 laptop, 2 wireless printers, all on an AC router. We do heavy streaming and downloading and gaming. So overall, it’s small, easy to setup (just a phone call to Comcast and give them the MAC address), and inexpensive modem that has been on for roughly 6 months now straight and not given me a single issue. It reboots very quickly and is easy to navigate once inside even for the most non experienced users. Buy it and don’t look back, especially if you can get a good deal used on it, oh and be sure to use Cat 6 and up cables for the best connection.
Top reviews from other countries
Levi Panipak
Activated or not let customers know that.
Reviewed in Canada on August 9, 2019
