What is upstream SNR margin?
The SNR-Margin for the Downstream is usually around 6db for a Line-Attenuation of 54db . It’s terrible and causes a lot of CRC errors. While, at the same time, the SNR-Margin for the Upstream is usually around 21db for a Line-Attenuation of 38db , and that is very good and almost never causes any CRC errors!
Is high SNR Margin good?
The higher the value, the better the line quality. The ‘Noise margin’ value should be 6 dB and higher. It can reach values up to 30 dB if a short wire is used.
How can I improve my SNR upstream?
To improve the upstream SNR margin on a DSL line, you’d either have to get the modem to transmit using more power, your you’d need to reduce the noise on the line (possibly by fixing faulty or degraded wiring). Unless your home’s telephone wiring is faulty, there’s not much you as a consumer can do to fix this.
Should SNR margin be high or low?
Higher ratios means better cables. Below 10dB is very bad and more than 20dB is good. At higher ratios, more speed can be achieved and lower ratios mean error-prone cable and lower speeds. The SNR margin is the difference between the SNR of the cable and the SNR needed to get an specific speed.
What causes low upstream SNR?
Low MER might be caused by low CNR, but it also might be caused by excessive phase noise in the data transmitter(s) at the other end; excessive nonlinear distortions in the transmission path (composite triple beat, composite second order, common path distortion, cross-modulation, etc.); in-channel ingress; excessive …
What is good SNR for VDSL?
7 dB to 10 dB — failures may occur; 11 dB to 20 dB — good line, no synchronization problems; 21 dB to 28 dB — a very good line; 29 dB and above — an excellent line.
What is an acceptable SNR margin?
On a good line, BT generally considers that a 6 dB SNR margin is appropriate to maintain a connection without a significant number of drops or errors.
What is good upstream SNR?
SNR (signal to noise ratio) levels: 256 QAM: 30 dB minimum. 33 dB or higher is recommended.
What are good upstream and downstream levels?
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. Good Downstream power levels are within -7 to +7 dBmV. Good Upstream power levels are within 38-48 dBmV.
What is a good downstream SNR?
In the Downstream section, identify the Modulation and Power to find verify SNR levels are within the acceptable range for each downstream channel. Acceptable SNR Levels (dB): If QAM64, SNR should be 23.5 dB or greater. If QAM256 and DPL( -6 dBmV to +15 dBmV) SNR should be 30 dB or greater.
What should be SNR margin for ADSL?
In most cases, a broadband connection can work well with an SNR margin of 3 dB. When a broadband connection is first made live, a default target SNR margin is set. For a BT-based ADSL or ADSL2+ broadband service, this is 6 dB.
What is a good SNR/SNR margin?
SNR margin = 45-35 = 10db. Higher SNR/SNR margin numbers indicate cleaner/stronger signals, with less background noise. The higher the SNR margin the more stable the connection. In some instances interleaving can help raise the noise margin to an acceptable level.
What is SNR margin and line attenuation?
Line attenuation. SNR Margin is a value to set in order to get the speed you desire. It’s the difference between the actual SNR (dB noise) and the line attenuation required to sync at a specific speed. This also depends on the ADSL technology, ADSL (up to 8 Megabits), ADSL2 (up to 12 Megabits) or ADSL2+ (up to 24 Megabits).
What is SNR margin tweaking and how does it affect broadband speeds?
With SNR margin tweaking, your downlink broadband speeds are no longer dictated by equipment (shown above) in the BT exchange. SNR margin adjustment could more than double your downlink connection speed on its own!
Can BT increase my downlink target SNR margin to 18 dB?
BT can increase your downlink target SNR margin to 18 dB When your broadband service is first switched on, the target SNR margin is set by the BT exchange equipment at 6 dB. On a good line, BT generally considers that a 6 dB SNR margin is appropriate to maintain a connection without a significant number of drops or errors.