5-GHz Antennas
Although most indoor 5-GHz products use permanently attached antennas, there is a big push to move 5 Ghz to the bands permitting external antennas. Presently, only a few antennas are available for the 5-GHz WLAN products, and many of them are similar to those found in 2.4 GHz. As a comparison, a 5-GHz 28-dBi parabolic dish is shown in Figure B-12. This particular antenna, from Maxrad, is about the same physical size as the 21-dBi 2.4-GHz dish antenna. Notice, however, that the gain is quite a bit higher for the same size, and the beam width is drastically reduced (12 versus 4 degrees). This will continue to be the case for 5-GHz antennas. For similar-gain antennas, a 5-GHz antenna will be approximately half the physical size.
Figure B-12. 28-dBi 5-GHz Parabolic Dish Antenna
 Table B-10 lists the specifications for a high-gain (28-dBi) 5-GHz dish antenna.Table B-10. 28-dBi 5-GHz Antenna Specifications | Parameter | Specification |
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| Frequency range | 5.7255.825 GHz | | VSWR | 1.5:1 nominal | | Gain | 28 dBi | | Polarization | Vertical or horizontal | | Azimuth (3-dB BW) | 4.75 degrees | | Elevation (3 dB BW) | 4.75 degrees | | Maximum power | 4 watts | | Temperature (operating) | 30C min, +60C max | | Mounting | 1.52.5" mast mount | | Wind speed (operational) | 100 mph | | Wind speed (survival) | 125 mph | | Dimensions | 25" diameter |
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