What should my cable modem signal levels be?

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.

Keeping this in consideration, what should my modem signal levels be?

Downstream (Rx) Signal Levels: -7 dBmV to +7 dBmV are "Recommended" values. -8 dBmV to -10 dBmV / +8 dBmV to +10 dBmV are "Acceptable" values but out of spec from ISP. A technician should still fix this to get to recommended levels.

Subsequently, question is, what is a good dBmV? Generally speaking the signal should be for DownStream between - 10 dBmV to + 10 dBmV . Ideally at 0dBmV and SNR 36~40 dB range. For CGN3 you should have 20 channels bonded. And UpStream is normally 36~51 dBmV and with 3 Channels bonded.

Furthermore, what should the SNR be on a cable modem?

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. If QAM256 and DPL(-15 dBmV to -6 dBmV) SNR should be 33 dB or greater.

How do I fix my cable modem signal?

Cable modem router troubleshooting tips

Make sure that your cable modem's MAC address is registered with your cable provider.
Check your cable modem's Ethernet and coaxial cable connections.
If you are using wireless, check that your wireless connection is functioning correctly.
Power off your modem for at least 10 seconds and then power it back on.

35 Related Question Answers Found

How do I check modem signal strength?

How to Measure Received Signal Strength

Press and hold the Alt key while clicking on the Wi-Fi icon on your status menu.
On the list of available networks, find the name of the network you are connected to, and the connection information including RSSI will be displayed immediately below.

How do I increase the signal to noise ratio on my cable modem?

High noise or low power levels reduce the SNR and can negatively affect your Internet connectivity, resulting in data loss or slow speeds.

Inside Wiring

Remove excess cable running to the modem.
Remove cable splitters.
Check for old or damaged cabling.
Check the connection to the modem.

What is a good WiFi signal strength?

Ideal Signal Strength

For higher-throughput applications like voice over IP or streaming video, -67 dBm is better, and some engineers recommend -65 dBm if you plan to support mobile devices like iPhones and Android tablets.

What is a good signal to noise ratio for cable modem?

The downstream SNR tells how much noise is on the cable. Again, for the cable modem to work within the specification, the SNR needs to be at least 23.5dB; a desirable ratio is 30 dB or higher.

What is RX power level?

The Tx level is the power in decibels per milliwatt (dBm) at which a modem transmits its signal. The Rx level is the power in dBm of the received signal. If the Rx level is under -25 dBm, the Signal-to-Noise Ratio (SNR) is likely to decrease, meaning that the speed also decreases.

How many channels do I need on my modem?

Any new modem you buy should have at least 16 downstream channels; anything less is probably either old or underpowered.

How do I check cable signal strength?

Point A being nearest to your TV and Point B being the other end of the cable.

Disconnect all TVs.
Short point B (so connect the signal and shield with a wire)
Test point A with a multimeter set at Ohm.

What is a good SNR level?

Ideally, you want to aim for a higher SNR. I'd say 20 dB or greater is good SNR. Greater than 40 dB is even better! Recommended minimum SNR for data is 18 dB and for voice over wifi it is 25 dB.

Is a higher SNR better?

Higher numbers generally mean a better specification, since there is more useful information (the signal) than there is unwanted data (the noise). For example, when an audio component lists a signal-to-noise ratio of 100 dB, it means that the level of the audio signal is 100 dB higher than the level of the noise.

How do I lower my upstream cable modem?

Disconnect your cable modem from the coax and power outlet then move it to the first coax jack. Reconnect the coax followed by the power. Test your signal levels again. 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.

How do I check my Comcast modem signal strength?

Click the "Signal" tab. Look at the numbers next to "Signal to Noise Ratio" in the Downstream section. While numbers over 30 indicate a strong signal, numbers under 30 are considered low.

How do I test my cable modem?

Steps

Understand the basic terminology.
Find your modem's diagnostics page.
Login to your modem.
Check the status of each of the modem's stages.
Evaluate the power levels.
Check the SNR values.
Review the event log.
Unplug the modem.

What do you mean by signal to noise ratio?

Signal-to-noise ratio. Signal-to-noise ratio (abbreviated SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to the noise power, often expressed in decibels.

What are upstream and downstream channels?

A downstream cable "channel" sends data from the cable company "headend" to you. Upstream channels use narrower channels of bandwidth between 200kHz and 6.4 MHz, but typically 3.2MHz with a typical throughput (in modern systems) of 27 Mbit/sec. 4 channels is 4 times that (108 Mbit/sec).

What are bonded channels cable modem?

measures of a modem are speed and performance, which are dictated by the number of channels it has. Channel bonding combines multiple channels—or lanes—to increase the amount of traffic that a modem's highway can comfortably support. Now think about traffic going in and out of a city on a two-lane road.

How can I lower my SNR?

Luckily, there are some things you can do to improve the SNR margin:

Buy a router that is good enough to manage low SNR margin figures.
Install a good quality ADSL filter to your router and to each phone device installed on the same line.
Try to change the ADSL provider, as some providers are less crowded than others.

What does negative dBmV mean?

Nothing unusual about negative dBmV levels. It just means the power received is less than the reference level of 1 millivolt. Maybe the cable down the street was damaged and this has weakened the signal level a bit and causing slower speeds.