User Guide

PMP 450 Planning Guide Glossary
DFS for 5.4 GHz Radios
Dynamic Frequency Selection (DFS) is a requirement in several countries and regions for 5 GHz unlicensed
systems to detect radar systems and avoid co-channel operation. DFS and other regulatory requirements drive
the settings for the following parameters, as discussed in this section:
• Country Code
• Primary Frequency
• Alternate 1 and Alternate 2 Frequencies
• External Antenna Gain
On the AP, the Home => DFS Status” page shows current DFS status of all three frequencies and a DFS log of
past DFS events.
Figure 33 AP DFS Status
Background and Operation
The modules use region-specific DFS based on the Country Code selected on the module’s Configuration,
General page. By directing installers and technicians to set the Country Code correctly, the operator gains
confidence the module is operating according to national or regional regulations without having to deal with
the details for each region.
Some regions have requirements to avoid certain 5.4-GHz frequencies used by some weather radar. To meet
this requirement, modules set to Europe will display the certain channel frequencies shown in page 3-21 on the
AP’s Carrier Frequency pop-up and on the SM’s Frequency Scan Selection List.
Table 70 on page 3-19 shows the details of DFS operation and channels available for each Country Code,
including whether DFS is active on the AP, SM, which DFS regulation apply, and any channel restrictions.
DFS does not apply to 4.9 GHz.
pmp-0047 (March 2014)
3-17