RF Arresting Characteristics
RF signals are circadian and alter in time continuously. The cardinal of cycles that action in the signal
per additional is its frequency, which can alter throughout what is referred to as the frequency
spectrum. The assemblage of abundance is hertz (Hz), and wireless LAN signals abatement almost into the
2.4-GHz and 5-GHz portions of the abundance spectrum. The action of accentuation causes the
RF arresting to absorb a allocation of the abundance spectrum, which is accepted as bandwidth.
In accession to frequency, an RF arresting at any time has specific amplitude. There are abounding means to
represent arresting amplitude, but the best accepted with RF systems is arresting power. The applicable
unit for ability is watt (W) or decibels about to 1 milliwatt (dBm). The FCC has rules for
maximum transmitter achievement depending on the accepted in use. For example, the maximum
transceiver achievement for 802.11b is 1 W. In general, college address ability enables longer-range
operation.
Most wireless LAN systems accept RF signals that abatement into the milliwatt (mW) range, which makes
the accession and multiplication of RF signals mathematically difficult. As a result, it is
Appendix G: IEEE 802.11 Fundamentals
advantageous to catechumen watts to dBm, which is a logarithmic amount that references the signal
power to 1 mW. The about-face blueprint is as follows:
dBm = 10 log (mW)
For example, 100 mW equals 20 dBm.