Taken from page 92 of our text, ?The reference point that relates the logarithmic relative decibel (dB) scale to the linear milliwatt scale is known as the dBm. This reference point specifies that 1 mW= 0 dBm and is a measurement of absolute power.? From this I gather that the dB of 1W must be 30, since the signal increases 103, or 1000 times.

The EIRP of the mentioned wireless device would be figured as such:

9 dBi = 3 dBi ? 3, so the signal gain is doubled three times.

200 mW ? 2 = 400 mW
400 mW ? 2 = 800 mW
800 mW ? 2 = 1600 mW

-6 dB = -3 dB ? 2, so the signal is halved twice.

1600 mW ? 0.5 = 800 mW
800 mW ? 0.5 = 400 mW

This is still not right. OK, I’ll throw two equations your way. You got #1 right, but here is the equation anyway….dB = 10 x (LOGx) where X = mW. That should have gotten you the 1mW = 0dB answer. So with that equation in mind find the dB for 200mW, then use that in the following equation. EIRP = device output in dB + gain – loss. teacher’s comment

Ok PLEASE someone show me how to work this problem and then show me how You got the answer.