Specifications
FRITZ!Box Fon WLAN 7270 142
Frequency Ranges
Channels located directly next to each other in the 2.4-
GHz band may overlap and result in mutual interference.
For instance, if several WLANs are operated close to each
other in the 2.4-GHz frequency range with a bandwidth of
20 MHz, a distance of at least five channels should be left
empty between each two channels used. This means that
if channel 1 is selected for one WLAN, the channels 6
through 13 can be selected for a second WLAN. This main-
tains the minimum distance between channels.
WLAN Autochannel With the WLAN autochannel function, the FRITZ!Box auto-
matically searches for the channel subject to the least
interference. Should problems with interference persist
despite this function, try to identify the source of interfer-
ence and switch it off manually.
Additional tips on interference in the WLAN radio network
are presented in the section “Ruling Out Interference
Cause by Other Wireless Networks” from page 117.
5-GHz Frequency
Band
The FRITZ!Box can operate in the 5-GHz frequency band as
an alternative. This frequency range is used much less of-
ten than the most common 2.4-GHz frequency range.
In the 5-GHz frequency band, your FRITZ!Box occasionally
may change channels unexpectedly due to DFS (Dynamic
Frequency Selection) if a “higher-privileged user” simulta-
neously claims the channel selected by the FRITZ!Box.
This can happen especially when military or civilian radar
is used in the immediate vicinity.
A prerequisite for use of the 5-GHz frequency band is that
all WLAN devices in the network support this frequency
range in accordance with the IEEE 802.11a or IEEE
8002.11n standard.
2.4GHz or 5GHz The FRITZ!Box works in the WLAN network either in the
2.4-GHz range or in the 5-GHz range, but not parallel in
both frequency ranges at the same time.
Bandwidth In both frequency ranges you can select between channel
bandwidths of 20 MHz or 40 MHz (exception: channel 140
in the 5-GHz frequency band). The FRITZ!Box initially at-
tempts to select a channel with 40 MHz bandwidth
(throughput up to 300 Mbit/s). If this is not possible due
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