2) In a token ring network, a computer station is downstream from any station through which the token on the ring has already passed. The power level on all downstream appears to be good (1.5-3.3). Is my modem broken? So basically I … RF signal levels affect nearly every part of a cable network’s operation: headend/hub site, optical fiber links, coax distribution, subscriber drops, and customer premises equipment (CPE). By Ron Hranac. Hello, I have the CM1000 Firmware V2.01.15 cable modem and so far its been great. 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. Optimum cable network downstream performance requires that radio frequency (RF) signal levels be measured and set correctly. Also, the signal to noise ratio is 0 on one of the downstream channels (between 38.3 and 39.0 on all others.) I have no trouble with the downstream channels, all 24 are locked. Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID 1 355000000 7.4 40 256 qam 28 2 267000000 7.5 40 256 qam 17 3 275000000 7.9 40 256 qam 18 4 283000000 7.8 40 256 qam 19 5 … If I unplug the cable modem, the problem goes away. 3) In CATV, a downstream channel is one used to transmit signals from the headend to the user. Hello, I have a Netgear Nighthawk AC1900 c7000v2 Cable Modem Router. fc1 is carrier for downstream ( that is cable modem receives on this frequency) fc2 is carrier for upstream ( that is cable modem transmit on this frequency) When u1 has to some data such as e mail to send across internet, it will use fc2 to send email to email server on internet. Downstream Modulation 64 or 256 QAM Capture Bandwidth Dual 32 MHz Capture windows Maximum Theoretical Data Rate DOCSIS 343.072 Mbps (8 channels) / 42.884 (single channel) @ 256 QAM at 5.36 Msym/s EuroDOCSIS 444.928 Mbps (8 channels) / 55.616 (single channel) @ 256 QAM at 6.952 Msym/s Bandwidth DOCSIS ≤ 48 MHz EuroDOCSIS ≤ 64 MHz An upstream channel is one in another frequency band that is used to send signals from the user back to the headend. The upstream channels, however, only half of them lock (channels 1-4). My modem is a fairly new Cisco DPC3008. 1) Is there a way to edit my cable modem settings and get it to negotiate a different downstream frequency? Any advice on improving my internet? I changed the Frequency start Value from 975000000 to 807000000 and … It's a 24x8. It has 8 downstream and 4 upstream channels. Rarely, however, is accurate signal level measurement as simple as connecting a piece of test equipment to a test point or signal source output connector. (561mhz vs. 567mhz). To view the upstream and downstream power levels: Launch a web browser from a computer or mobile device that … However, the power level on 1 of the upstream is 0. Good Downstream power levels are within -7 to +7 dBmV. Measurement of a cable network’s downstream RF signal levels is often taken for granted and assumed to be fairly straightforward. D3 is a wondrous improvement over earlier DOCSIS versions as it allows for a much higher maximum throughput. Downstream (Rx) Receive Power Level: This is the amount of signal received by the modem from the transmitter in the cable company head-end. Simply put, a higher throughput means greater bandwidth and faster speeds. For all modems DOCSIS 3.0 / 3.1: I noticed that the problem channel is only 6mhz away from the cable modem downstream frequency, and I suspect this is the problem. as i cant get anywhere with virgin. Good Upstream power levels are within 38-48 dBmV. The other half (5-8) won't lock. 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