Aerohive HiveAP 28, Руководство по развертыванию

Страница: 9 / 17

Deployment Guide 37
H
IVE
AP P
RODUCT
O
VERVIEW
Antennas
The HiveAP 28 includes two detachable single-band antennas with 8dBi gains (802.11b/g) and two detachable
single-band antennas with 10dBi gains (802.11a). These antennas are omnidirectional, providing fairly equal
coverage in all directions in a toroidal (donut-shaped) pattern around each antenna. When the antennas are
vertically positioned, coverage expands primarily on the horizontal plane, extending horizontally much more than
vertically. See
Figure 3 , which shows the toroidal pattern emanating from a single vertically positioned antenna.
Note that when high gain antennas are added, the torus shape becomes somewhat elongated or compressed. If the
HiveAP 28 is mounted higher than 20 feet the center of the torus curves inward so that the connection quality,
directly underneath the center of the HiveAP 28, becomes compromised.
To change coverage to be more vertical than horizontal, position the HiveAP so that the antennas are on a
horizontal plane. You can also resize the area of coverage by increasing or decreasing the signal strength.
Figure 3 Omnidirectional Radiation Pattern
The pairs of antennas operate concurrently in two different frequency ranges: 2.4 GHz (IEEE 802.11b/g) and 5 GHz
(IEEE 802.11a). Using two different frequency ranges reduces the probability of interference that can occur when
numerous channels operate within the same range. Conceptually, the relationship of antennas and radios is shown in
Figure 4 . (For information about attaching the antennas to the HiveAP 28, see "Attaching Antennas" on page 42 .)
Figure 4 Antennas and Radios
\
Note: The HiveAP 20 uses
interface interface radio antenna external
command to enable an
external antenna attached to it. Entering this command on the HiveAP 28 disables the antenna on the
opposite side of the device from the radio to which the interface is linked and results in a loss of diversity.
Note: To show the shape of radiation more clearly,
this illustration depicts the coverage provided by
only one active antenna and is not drawn to scale.
The omnidirectional antennas
radiate equally in all directions,
forming a toroidal pattern. HiveAP
The two 802.11b/g antennas link internally to Radio 1
and broadcast in the 2.4 GHz frequency range.
802.11a Main Antenna
802.11b/g Main Antenna
802.11b/g Auxiliary Antenna
802.11a Auxiliary Antenna
The two 802.11a antennas link internally to Radio 2
and broadcast in the 5 GHz frequency range.
Radio 1
RF 802.11b/g
2.4 GHz
Radio 2
RF 802.11a
5 GHz