On 09/21/2011 09:12 AM, Stephen wrote: > good point -xxDbm is lower is better it is essentially a > representation of signal loss. > Well, not quite. It is an expression of a ratio against a standard value.
dBm is a measurement of power, meaning "Decibels relative to One Milliwatt". Decibels themselves work on a logarithmic scale and express the ratio between two values. Examples: If a signal is 10 milliwatts, its power level could be expressed in dBm as: 10*log10( 10mW / 1mW) = 10*log10(10) = +10dBm A signal of 1 microwatt is: 10*log10( 1uW / 1mW) = 10*log10(0.001) = -30dBm 1 watt = +30dBm, 1 picowatt = -90dBm, 100 femtowatts = -100dBm, etc.. A Linksys router transmitting at a power level of 250 mW, represents a power level of +24dBm. (You won't measure this outside of the unit, of course. It represents the power the unit is pushing into its antenna) But, I digress.... Note the importance of the sign. Cheers, KevinO --------------------------------------------------- PLUG-discuss mailing list - PLUG-discuss@lists.plug.phoenix.az.us To subscribe, unsubscribe, or to change your mail settings: http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss