Computers| Computers |
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11-11-2006, 05:43 PM
| #1 (permalink) |
| Newb Techie Join Date: Nov 2006
Posts: 1
|  Attenuation and Signal to noise Ratio Hi, I have 1 homework problem which I just dont understand... All the terms are confusing me. A transmission medium has a -3dB per 100-meter attenuation characteristic. The receiver on one end of the medium can correctly interpret signals if the signal to noise ratio is above 20dB. What initial signal level is necessary to allow for transmission over 1km? So how shld i go about? Any hints will be appreciated... |
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11-12-2006, 03:06 PM
| #2 (permalink) |
| Super Techie Join Date: Jul 2006
Posts: 423
| I can not answer your question exactly, except for the " to broadcast over 1 km " . Most WI FI routers put out a 30mw signal, very weak. You probably would need to get an industrial 1 02 2 watt amp http://www.hyperlinktech.com/web/24ghz_amplifiers.php
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11-14-2006, 12:57 AM
| #3 (permalink) |
| True Techie Join Date: Dec 2002
Posts: 158
| Isnt this simple math? you get a 3 db loss every 100 meters? and you need to go 1k meters? But you need to be above 20db for an snr? 3 x 10 = 30 +20 = 50 So you would need 50 for an snr in order to go 1k meters if you have a 3db loss every 100 meters. They only care about the snr though? not the Tx power? Thats weird, its a one way system? Hope that helps.
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