How to Increase the SNR of a Wireless Signal
Signal-to-Noise ratio (SNR) is defined as the signal divided by the noise, both measured on the same power scale. When measured in decibels, a logarithmic scale, both signal and noise are negative numbers and SNR is computed as: SNR (db) = Signal (db) - Noise (db), for example: SNR = (-80) - (-98) = 18. SNR is a composite measurement of how fast wireless data travels and how far a wireless signal reaches. A higher SNR is better, and acceptable SNR is typically in the range from 8 dB to 25 dB, with 8 dB supporting a data rate of 6 megabits per second (Mbps) and 25 dB supporting a full 54 Mbps data rate. To increase your SNR, try these suggestions for increasing the strength of the wireless signal.
Instructions
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A wireless signal gets weaker the further it travels from the router, which means SNR also decreases with distance. For a simple method to improve SNR, place the router and the client physically closer to one another.
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Double the transmission power of your wireless router to improve the signal output and the corresponding SNR. For example, if your signal is -85 and your power is 100 milliwatts (mW), you can improve your signal to approximately -82 by doubling the router's transmission power to 200 mW.
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Install an antenna with increased gain on your wireless router to improve the signal and SNR. Replace a standard 3 dB antenna with a 12 dB antenna to get an additional 9 dB of signal. For example, if your signal was -82 with a 3dB antenna, it should increase to -73 with a 12 dB antenna.
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Tips & Warnings
In order to change settings such as the router's transmission power, you may need to flash your router with advanced firmware such as the free, open-source "dd-wrt" firmware.
Increasing the power of your wireless router can also increase the noise level, which decreases the SNR.
References
Resources
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