User guide

March 2005 Designing Your Canopy Network
Through Software Release 6.1
Page 114 of 425 Issue 1
Canopy System User Guide
12.6.3 Avoiding Self Interference
For 5.2-, 5.4-, and 5.7-GHz modules, 20-MHz wide channels are centered every 5 MHz.
For 2.4-GHz modules, 20-MHz wide channels are centered every 2.5 MHz. This allows
you to customize the channel layout for interoperability where other Canopy equipment is
collocated.
CAUTION!
Regardless of whether 2.4-, 5.2-, 5.4-, or 5.7-GHz modules are
deployed, channel separation between modules should be at least
20 MHz.
Physical Proximity
A BH and an AP on the same tower, or separated by less than 100 vertical feet
(30 meters), require a CMM. The CMM properly synchronizes all Canopy modules to
prevent interference and desensing of the modules. At closer distances without sync, the
frame structures that these modules transmit and receive cause interference.
Spectrum Analysis
In Release 4.1 and later releases, you can use an SM or BHS as a spectrum analyzer.
See Mapping RF Neighbor Frequencies on Page 98.
Power Reduction to Mitigate Interference
In Release 4.1 and later releases, where any module (SM, AP, BH timing master, or BH
timing slave) is close enough to another module that self-interference is possible, the
operator can set the SM to operate at 18 dB less than full power. The Power Control
feature provides this functionality. To enable this functionality, perform the following
steps.
CAUTION!
Selection of Low can cause a link to a distant BHS to drop. If a link
drops when Power Control is set to low, the link can be re-established by
only Ethernet access.
Procedure 3: Invoking the low power mode
1. Access the Configuration page of the module.
2. In the Power Control parameter, click Low.
3. Click Save Changes.
4. Click Reboot.
5. Access the Alignment page of the SM.