Siemens SCALANCE W1780 Configuration Manual page 226

Configuring with Web Based Management
6.6 "Interfaces" menu
● DFS (802.11h)
Enables or disables the "Dynamic Frequency Selection (DFS)" function.
– Enabled
● Outdoor Mode
– Enabled
– Disabled
● max. Tx Power
Specify the maximum possible transmit power of the device.
If the transmit power is set too high, the received signal at the client might be over
modulated. Check the received signal strength at the client (dBm).
It may be necessary to reduce the transmit power depending on the antennas being used
to avoid exceeding the maximum legal transmit power. Reducing the transmit power
effectively reduces cell size.
Note
The maximum possible transmit power varies depending on the channel and data rate. For
more detailed information on transmit power, refer to the documentation "Characteristics
801.11ac SCALANCE W1700".
Note
If both interfaces of an access point are operated in the same frequency range, this may
cause wireless interference on one or both interfaces at a transmit power higher than 15
dBm.
226
With the DFS function, it is possible to also use the higher 5 Ghz channels.
These channels are country-specific and are subject to certain DFS regulations. You can
find additional information on this in the country-specific DFS documentation.
Before the access point transmits over one of these channels, it checks for competing
radar signals for 60 seconds according to the CAC (Channel Availability Check). The
access point also does not send any beacons for the duration of the search. With
weather radar channels (5.6 - 5.65 GHz), the duration of the search is 10 minutes.
If no radar signals are detected after the search period has elapsed, the access point
transmits on the channel. Otherwise, the access point changes channel and repeats the
check.
The access point also searches for radar signals continuously during operation.
If the access point discovers a radar signal on the current channel, it changes
automatically to an alternative DFS channel and the current channel is blocked for 30
minutes.
Note
Use 160 MHz channel bandwidth
Channels available for operation at 160 MHz only if DFS is activated.
Disabled
The DFS function is not used.
If you have enabled Outdoor Mode, only the channels that are permitted for outdoor
operation are available to you.
If you have disabled Outdoor Mode, only the channels that are permitted for operation in
a building are available to you.
SCALANCE W1780/W1740 according to IEEE 802.11ac Web Based Management
Configuration Manual, 11/2019, C79000-G8976-C485-03