VIZMONET BreadCrumb Wireless Nodes (ES1-2450R) : User's Guide : Page 42

1 minute completes without detecting radar, the radio can then start normal operation on the chan-

nel while still continuously checking for radar. Note: Channels from 5600 MHz to 5650 MHz, if availa-

ble, may have a 10 minute CAC period.

• If radar detection is triggered on a DFS channel, that radio will stop transmitting for 30

minutes (the Non-Occupancy period aka NOP). Warning code 382 “Radar detection paused radio:

wlanN (wlanN …)” will be displayed in BC|Commander if the affected unit was able to report its

warning status over another radio or over ethernet.

• When the 30 minute NOP period of not transmitting completes, before reusing the DFS chan-

nel, the radio must not transmit for 1 additional minute (may be 10 minutes for 5600-5650 MHz)

while pre-checking for radar (a CAC period). If no radar is detected during the CAC period, normal ra-

dio operation is resumed with continuous checking for radar.

• When resuming normal operation after a radar detection, the radar detection warning 382 will

be removed from the radio and a warning 383 “Radio resumed from radar pause: wlanN (wlanN, …)”

will be added. This 383 “unpaused” warning will remain up for 12 hours so that personnel will know

what radios were affected by DFS stoppages. Warning 383 will be removed when all listed radios

have been aged out.

About Radar Detection

Radar is detected as pulses (spikes) of radio frequency (RF) noise. If pulses of noise make it past several

range checks, and the pattern of pulses is sufficiently similar to a radar pattern, a radar detection event

will occur. False detections may be caused by anything that creates RF interference including electrical

equipment, improperly positioned antennas, nearby wireless radio devices and RF reflections caused by

antennas too close to the ground, walls or other RF-reflecting surfaces.

If possible, use of DFS channels should be avoided for critical network paths, especially if the Bread-

Crumb has no other wired or wireless network connections to the mesh.

DFS Additional Antenna Separation

For 5 GHz transceivers using channels that require DFS radar detection, it is recommended to mount

each antenna for a DFS channel at least 2 feet from any other 5 GHz transceiver’s antenna.

Note: Two new DFS-related fields can be examined in BCAPI Explorer. For wireless DFS channels, these

fields will indicate the count of RF interference pulses encountered as well as a count of how many were

deemed sufficiently similar to radar by the radar pattern detector.

• state.wireless[n].stats.pulseEvents – Raw count of interference pulses detected by the radio

• state.wireless[n].stats.radarDetections – Count of pulses that triggered radar detector

TDWR

Terminal Doppler Weather Radar (TDWR) operates in the frequencies 5600-5650 MHz. TDWR helps pro-

tect airplanes from hazardous weather such as wind shear and gusts. Wireless network installations with-

in 35 km of or in line-of-sight of a TDWR must not use TDWR frequencies and should avoid using channels

within 30 MHz of the TDWR frequencies. A list of U.S. TFDR radar coordinates may be found at WISPA.org:

WISPA.org - see TDWR Resources

Warning

Operating this equipment in violation of Local, Regional or National Standards, including interfering

with radar, is likely to result in substantial sanctions to the User, including fines, imprisonment, confis-

cation of equipment, and other penalties as determined by your local regulatory authorities.