What is antenna diversity or receive diversity?
Antenna diversity is basically a move against indoor multi-path fading using spatial redundancy. When the signals emitted by a radio bounce off walls, ceilings, and other reflective objects in the environment, the reflections vary in space and frequency. Essentially the antenna receives several ‘copies’ of the signal, shifted in time, space and/or frequency. The receiver can only ‘see’ combinations of these signals. Nearly every 802.11b radio I’ve seen supports only receive diversity, if diversity is supported at all. When transmitting, only one antenna is used. Typical tests show a 3dB ‘system’ gain if diversity is present at both ends. So yes, in a free-space LOS situation, you shouldn’t care about antenna diversity. But its not so much that one antenna might receive something that that other does not, but rather that one antenna will ‘see’ a better signal, and the switches in the diversity section of the analog section will direct this better signal to the radio.
Antenna diversity is basically a move against indoor multipath fading using spatial redundancy. When the signals emitted by a radio bounce off walls, ceilings, and other reflective objects in the environment, the reflections vary in space and frequency. Essentially the antenna receives several ‘copies’ of the signal, shifted in time, space and/or frequency. The receiver can only ‘see’ combinations of these signals. Nearly every 802.11b radio I’ve seen supports only receive diversity, if diversity is supported at all. When transmitting, only one antenna is used. Typical tests show a 3dB ‘system’ gain if diversity is present at both ends. So yes, in a free-space LOS situation, you shouldn’t care about antenna diversity. But its not so much that one antenna might receive something that that other does not, but rather that one antenna will ‘see’ a better signal, and the switches in the diversity section of the analog section will direct this better signal to the radio. • I have mostly dire
