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From: Pete French <petefrench@ticketswitch.com>
Date: Wed, 27 Sep 2006 15:24:50 +0100
Cc: 
Subject: Re: 802.11 RSSI value displayed from ifconfig(8)
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> Hello, I would like to convert RSSI to dBm (in fact I would love if
> ifconfig cound display SNR in dBM), so I would like to know if this
> formula is any right:

Take a look here:

http://www.wildpackets.com/elements/whitepapers/Converting_Signal_Strength.pdf

Especially at the top of page 5. RSSI isn't defined to be in particular
units, so the formula will be different for each piece of radio hardware
you have. Unless you have a way of calibrating your specific interface
then you probably cant do it in any meaningful way.

-pete.