Strength Not Power

As wireless communications remains the most cost effective solution for a significant amount of modern remote control/monitoring or telemetry applications, there still remain a number of misunderstood concepts regarding a data radio network performance. The biggest of these is that more power means greater coverage.

This concept is only the case when comparing identical data radios. It is true to say that if you increase the power on the radio you will get greater coverage. However to compare the power output level of one digital data radio with another from a different manufacture and to say that the unit with the higher power will communicate further is not correct.
You must compare the receiver sensitivity of both units at the appropriate data rate and channel spacing and combine that with the power levels in order to make a technical comparison. Furthermore if one device is using forward error correction (FEC) and the other is not, this can be worh as much as 5dB in equivalent signal recovery, or to put it in to power terms, nearly 4 times the transmit power.