VIZMONET BreadCrumb Wireless Nodes (ES1-2450R) : User's Guide : Page 41

(5680 MHz) and HT40-, and if a second radio is present, its default channel and mode is 100 (5500 MHz)

and HT40+. In other countries the default channels may differ based on local regulations.

Note

If the default channels aren’t available, the default will instead be the first valid channel (in order of

channel number) with the largest bandwidth (up to 20 MHz) that doesn’t conflict with other radios. If

that fails, meshing will be disabled on that radio.

Some 5 GHz channels support HT40 mode. In this mode, the radio binds two standard 20 MHz channels

to obtain a wider bandwidth 40 MHz channel. The + or - designation describes if the second channel is

above or below the base channel. Plus (+) indicates that the additional 20 MHz occurs above (at a higher

frequency than) the first 20 MHz while minus (-) indicates that the additional 20 MHz occurs below (at a

lower frequency than) the first 20 MHz.

Note

The 802.11n frequency noted is the center frequency of the base 20 MHz channel. This is different from

802.11a turbo mode where the frequency was the center of a single 40 MHz wide channel. HT40 opera-

tion (+ or -) is compatible with 802.11a 20 MHz and 802.11n HT20 modes. HT40 operation is NOT com-

patible with 802.11a turbo mode.

Caution

Most 5 GHz antennas only support a subset of the 802.11n 5 GHz frequency channels the Rajant radio is

capable of operating at. Before changing the channel of a 5 GHz radio, verify that the channel is sup-

ported by the connected antenna.

IMPORTANT: Regarding indoor-only frequencies

In regions where radio frequencies are regulated by ETSI (CE), the frequency range 5170-5350 MHz is re-

stricted to indoor use only. Check local regulations before using these channels.

IMPORTANT

In many regions where radio frequencies are regulated by ETSI (CE), a license is required to use chan-

nels in the frequency range 5735-5835 MHz (on models that offer these channels). Check local regula-

tions before using these channels.

IMPORTANT

In Canada, a license is required to use channels in the frequency range 5150-5250 MHz (on models that

offer these channels). The license may restrict transmit power. Licensing information may be found at

http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf11294.html

A.3 DFS and TPC

DFS and TPC for 5 GHz Channels

Many channels in the 5 GHz band are subject to regulations that require active avoidance of interference

with weather radar and other radars (Dynamic Frequency Selection aka DFS). In many countries, regula-

tions also require lower transmit power for nearby wireless connections (Transmit Power Control aka

TPC) on the same channels. These DFS channels may be available for use in some countries on Bread-

Crumbs with 5 GHz radios that provide hardware support for radar detection.

The list of 5 GHz channels that are subject to DFS and TPC depends on the regulatory domain of the re-

gion of operation. In many regions any available channels from 5260-5700 MHz require DFS, or DFS and

TPC. In some regions, additional channels require DFS and TPC.

DFS channels will not be available immediately upon startup and will become non-operational for a fixed

period of time after radar or any radar-like pulse of noise is detected.

BreadCrumb DFS Behavior

• After power-on or restart, all transmits on a DFS channel will be disabled for 1 minute (typical)

while the radio pre-checks for radar on that channel (the Channel Availability Check aka CAC). If the