Cable modem upstream power. For every 100 meters (328 feet) of RG-6, there will be 2.

Cable modem upstream power Upstream Power / Modulation(35dBmV to 55dBmV) - the strength of signal transmitted by the cable modem Generally a lower this number is Feb 7, 2022 · The upstream power does not work the way you think. A channel is a section of the spectrum that has a predefined width and location so that your cable modem and cable company can communicate. . -8 to +8 dBmV is acceptable for Gateways; -10 to +10 dBmV is acceptable for Cable Modems on the downstream channels. Given that my cable modem is a DOCSIS 3. You can remove splitters on the line if you need to raise and clean up your signal level a bit. Cable modems work best if the downstream signal level is within +/-15dbmV, and the upstream power is between 37dbmV and 55dbmV. 8 dBmv. When this happens, the blinking pattern of the cable modem's lights will look fairly similar to a fresh boot. Oct 2, 2024 · 75-ohm RG-6 is the typical coax cable type you'll find in your home. Dec 6, 2016 · Downstream and upstream power levels are important when determining if the cable line that is connected to your cable modem or modem router is receiving sufficient power. This needs to be under 50 to really be stable for 3 upstream channels. A low upstream power number generally means the cable company equipment is receiving good signal levels from you. I was able to remove one of the splitters in the line… Sep 26, 2020 · The upstream power level is controlled automatically by Comcast's equipment. 64 QAM to 16 QAM or 16 QAM to QPSK) if the upstream transmit level is Cable modem upstream transmit power. A DOCSIS 3. Jan 1, 2011 · Note that constant power-per-carrier and constant power-per-hertz operation are not the same as long loop automatic level control (ALC), which is a CMTS cable-modem interaction mechanism to maintain the desired RF signal level — the commanded nominal receive power — at the CMTS upstream port as the return path’s attenuation changes That's in all the cable modems data sheets, but those specs are from testing in a laboratory which is the perfect environment that can not be achieved at home, no matter what. Mar 30, 2025 · Upstream Power Level (Tx)- This power level is the amount of signal transmitted by the modem back to the cable companies' receiver. Extended upstream transmit power is enabled and I cannot toggle that setting. Based on how much signal they receive they tell your modem to increase or decrease its power. The max length of a coax run depends on the transmit power of your modem and your ISP's transmitter. If the upstream power is still too high at the first jack, there is nothing you can do on your end to resolve the problem. Downstream Power Level Cable Modems -10dBmV +10dBmV Gateways and EMTAs -7dBmV +7dBmV Downstream Signal to Noise Ratio 35dB - Upstream Power Level +35dBmV +50dBmV Upstream Signal to Noise Ratio 31dB - Upstream Receive Power -2dBmV +2dBmV . 1 cable modem’s transmit power introduces This was the reply: The upstream power too high / out of spec for Comcast. If arris says 45-51dBmV is what their modem can reliably transmit to the CMTS and the loss is too low that it gives, say, 36dBmV, maybe it's good from a signal integrity perspective for the CMTS, but the modem itself may not actually be able to deliver a Accessing the modem’s internal pages is essential to view downstream and upstream power levels. It will work higher but if it gets to say 52 or 53 it almost always fails. Data-Over-Cable Service Interface Specifications (DOCSIS ®) CM upstream transmitters are designed to accommodate a wide range of net attenuation between each modem and the upstream burst receiver circuitry in a cable modem termination system (CMTS), converged cable access platform (CCAP), or remote PHY Sep 16, 2023 · A BIG clue: Upload channel power quality / STABILITY is critical: Cable modem upload channel power should remain very consistent throughout the entire day. The downstream has 32 channels. The modem's manufacturer says this is likely the issue, but my ISP insists they do not have control over this. I'd prefer to eliminate the powered amp as it will lose power during a power outage and I can't power it with my current battery backup. Aug 11, 2020 · The downstream power is on the low / weak side and it may be intermittently fluctuating even lower to out of spec levels. It allows you to monitor the performance of your cable modem and ensure that the signal levels are within acceptable ranges. I had the issue of my upstream levels hitting over 55 and would consistently reboot my modem. A cable modem running a higher upstream modulation rate may downgrade itself to a lower modulation rate (i. Test your signal levels again. That is transmit power and when the ISP gets too much signal it tells your modem to lower it value. When you see cable modem upstream power fluctuate/spike a moderate amount (I was seeing 3 to 10 dB) during the day, that is NOT normal, and indicates a problem to find. For every 100 meters (328 feet) of RG-6, there will be 2. Good Downstream power levels are within -7 to +7 dBmV. You want as close to zero as you can get. Your downstream levels are bad in both cases. Specification Min Max. You can also use a tap (directional coupler) to get a cleaner signal to the cable modem instead of a splitter. 8 dBmV when spec is 45-52. That's because what's important is not the level at the modem, it's the level (and quality) of the modem's signal as received at Comcast. Upstream Power / Modulation(35dBmV to 55dBmV) - the strength of signal transmitted by the cable modem Generally a lower this number is Hmm, there's signal quality which the CMTS can hear, sure, but there's the actual modem being able to reliably transmit that upstream power. If the signal is too strong on the downstream, or too low on the upstream, a tech may need to install an attenuator. Although most customers are probably operating in the 35 to 50 range, some work just fine with the modem upstream below 35 dBmV. So a worse signal makes the upstream power too high not too low. Jul 31, 2023 · Downstream Power Level : Cable Modems-10dBmV +10dBmV: Gateways and EMTAs-7dBmV +7dBmV: Downstream Signal to Noise Ratio: 35dB-Upstream Power Level +35dBmV +50dBmV: Upstream Signal to Noise Ratio: 31dB-Upstream Receive Power-2dBmV +2dBmV My cable modem is connected to a battery backup as I use my internet connection for VOIP and telepresence work. Ideally you want upstream around 40db. First Published: November 16, 2009 Last Updated: June 16, 2014 The Upstream Channel Bonding (USCB) feature helps cable operators offer higher upstream (US) bandwidth per cable modem (CM) user by combining multiple radio frequency (RF) channels to form a larger bonding group at the MAC layer. Here are Jul 7, 2014 · Upstream Channel Bonding. Jan 15, 2021 · Downstream Power Level Cable Modems-10dBmV +10dBmV: Gateways and EMTAs-7dBmV +7dBmV: Downstream Signal to Noise Ratio: 35dB-Upstream Power Level +35dBmV +50dBmV: Upstream Signal to Noise Ratio: 31dB-Upstream Receive Power-2dBmV +2dBmV You can remove splitters on the line if you need to raise and clean up your signal level a bit. If you add more cable (or a splitter) the modem has to 'try harder' (use more power) to get a good upstream connection. Opening the above-mentioned status page of the cable modem shows important information about each of those channels: Power Level; SNR (Signal to noise ratio) Corrected and uncorrectable packets My internet has been dropping periodically, and believe I have tracked it down to the upstream power levels being below spec for my modem. Reconnect the coax followed by the power. 5dBmV. e. It not only determines if the cable modem will be able to come online and register with the CMTS (cable modem termination system) but obtaining the optimal transmit power will make or break the subscriber’s quality of experience (QoE). Good Upstream power levels are within 38-48 dBmV. 1, Motorola MG8702 cable mode/router combo. Nov 17, 2021 · Cable diagnostics still indicate that the connection is poor due to upstream power. Nov 17, 2012 · Inability to communicate upstream shouldn't cause a cable modem to reboot, but it WILL eventually cause it to re-start the sign-on process from scratch, which can take quite some time. This feature ensures better signal Disconnect your cable modem from the coax and power outlet then move it to the first coax jack. What you’re looking at is the downstream and the upstream also called ofdm (Orthogonal frequency-division multiplexing). Dec 5, 2018 · The one that breaks things for most people is the upstream power levels. When choosing a cable modem, consider one with extended upstream power capability. com Dec 10, 2017 · The upstream power level is something that is controlled by the cable company equipment remotely. See full list on broadbandlibrary. When I connect the modem direct (no splitters or additional draws aside from the grounding block) the power level is still a rather high base of 45. If you put in a attenuator to lower the signal the ISP would just request your modem send at a higher rate. To view the upstream and downstream power levels: Launch a web browser from a computer or mobile device that is Jun 24, 2003 · On your cable modem manufacturer's page you might find terms such as: downstream SNR (signal to noise ratio), downstream power level, upstream SNR and upstream power level. 0dBmV and 35. Feb 22, 2022 · A cable modem’s transmit power is extremely important. Aug 13, 2015 · While my values are likely considered "within spec" per Comcast I really would like to reduce the upstream power levels to provide a little headroom. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels. 3dB of attenuation (signal loss) for the lower frequencies. 8-35. They're at 33. The upstream SNR level provided by the CMTS is not specific to any single modem, but is an averaged from all modems on that upstream channel on the upstream port. With my Internet Service Provider (ISP) and service plan, I get 16 downstream channels and 2 upstream channels. So splitters decrease downstream and increase upstream signal levels. This reading should certainly be lower than 54, depending on specifics about your cable companies equipment, as an absolute maximum, but would be better to be in no higher than the high 40s. Here's what all those mean, and a general guideline of what constitutes a problem: Downstream SNR shows the strength of the signal to your cable modem as compared to the The modem starts low and then uses higher and higher power until it makes a good connection to the headend. Upstream power signal level is currently running between 27. I assume that setting is part of Xfinity provisioning. leao xogvquu mgfv mxgbi jdcco rdyy hsn miqtnyb ekrmp wasl qmdvlff mqng qvhldr pkfhi hjg