Wireless operation
Chapter 1: Product description
1-18
phn-2510_002v000 (Mar 2012)
Radar avoidance
In regions where protection of radars is part of the local regulations, the PTP 250 must
detect interference from radar-like systems and avoid co-channel operation with these
systems.
The requirements for a master device are:
x
The device can only transmit on available channels, of which there are none at initial
power up. The radar detection algorithm will always scan a usable channel
for 60
seconds (channel availability check) for radar interference before making the channel
an available channel.
x
As a result of this compulsory channel scan, there is a service outage of at least 60
seconds every time radar is detected, and the installation time is extended by at least
60 seconds even if no radar is detected on the channel.
x
When operating on a channel, the spectrum monitoring algorithm implements a radar
detection function (in-service monitoring) which looks for impulsive interference on the
operating channel. If impulsive interference is detected, spectrum management will
mark the current operating channel as having detected radar (unavailable channel) and
initiate a change to an available channel. The previous operating channel will remain in
the unavailable state for 30 minutes after the impulsive interference pulse was
detected.
x
After the 30 minutes have expired the channel will be returned to the usable channel
pool.
There is a secondary requirement for bands requiring radar avoidance. Regulators have
mandated that products provide an approximately even loading of the spectrum across all
devices. In general, this prevents operation with fixed frequency allocations. However:
x
ETSI regulations do allow frequency planning of networks (as that has the effect of
spreading the load across the spectrum).
x
The FCC does allow channels to be barred if there is actually interference on them.
As the radar detection requirements for the band 5600-5650 MHz are more severe, the
Master device will not initiate any transmissions on channels which overlap this band.
Summary of Contents for PTP 250
Page 1: ...Cambium PTP 250 User Guide System Release 250 02 01 ...
Page 8: ...Safety and regulatory information VI phn 2510_002v000 Mar 2012 ...
Page 20: ...List of Tables xii phn 2510_002v000 Mar 2012 ...
Page 58: ...System management Chapter 1 Product description 1 30 phn 2510_002v000 Mar 2012 ...
Page 104: ...Limit of liability Chapter 3 Legal information 3 12 phn 2510_002v000 Mar 2012 ...
Page 122: ...Notifications Chapter 4 Reference information 4 18 phn 2510_002v000 Mar 2012 ...
Page 152: ...Installing the PoE power supply Chapter 5 Installation 5 30 phn 2510_002v000 Mar 2012 ...