CXtec NEW COMPATIBLE 2.2 DBI RUBBER DUCK ANTENNA WITH RPTNC FEMALE Guia De Especificaciones
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transmitter, plus the antenna gain, less any losses in coax, is equal to or less than +20 dBm. This drastically reduces the overall distance an outdoor
link can operate.
link can operate.
•
Amplifiers—Since the ETSI regulation has such a low EIRP, the use of amplifiers is typically not permitted in any ETSI system.
FREQUENCIES AND CHANNELS SETS
IEEE 802.11b Direct Sequence Channels
Fourteen channels are defined in the IEEE 802.11b Direct Sequence (DS) channel set. Each DS channel as transmitted is 22 MHz wide; however, the
channel center separation is only 5 MHz. This leads to channel overlap such that signals from neighboring channels can interfere with each other. In
a 14-channel DS system (11 usable in the US), only three non-overlapping (and hence, non-interfering) channels, 25 MHz apart, are possible
(for example, channels 1, 6, and 11).
This channel spacing governs the use and allocation of channels in a multi-access point environment such as an office or campus. Access points are
usually deployed in “cellular” fashion within an enterprise where adjacent access points are allocated non-overlapping channels. Alternatively, access
points can be collocated using channels 1, 6, and 11 to deliver 33 Mbps bandwidth to a single area (but only 11 Mbps to a single client). The channel
allocation scheme is illustrated in Figure 10, and the available channels in the different regulatory domains are defined in Table 4 on the following
page.
Figure 10. IEEE 802.11b DSSS Channel Allocations
Table 4 exhibits the channels permitted in the corresponding approval areas.
Table 4. DSSS PHY Frequency Channel Plan
Regulatory Domain
Channel
Frequency (MHz)
Americas (-A)
EMEA (-E)
Israel (-I)
Japan (-J)
1
2412
X
X
-
X
2
2417
X
X
-
X
3
2422
X
X
X
X
4
2427
X
X
X
X
5
2432
X
X
X
X
6
2437
X
X
X
X
7
2442
X
X
X
X