Cisco BR1400 Deployment Manual page 32

Pre-Survey checklist:
1. How far is the bridge link?
2. Do I have a clear Line of Sight?
3. What is the minimum acceptable data rate the link will run at?
4. Is this Point to Point or Point to Multi-Point?
5. Do I have the right antenna?
6. Have I used the Outdoor Bridge Calculation Utility to check my figures?
7. Do I have access to both of the Bridge site locations?
8. Do I have the proper permits if any are required? Sometimes you need permission from
Union workers, electricians, contractors or the building owner.
9. Do I have a partner? Never attempt to survey or perform work on a roof or tower alone.
10. Have I configured the Bridges before I go onsite? It is always easier to resolve simple
configuration or device issues beforehand then to encounter them "on site".
11. Do I have the proper tools and equipment to complete my task?
Tip: Cellular Phones or hand held two way radios are handy when performing surveys.
See the Bridge installation section for more tips on Surveys.
5 Interference Study
While the unlicensed spectrum offers the benefit of no licensing fees, users may pay a penalty in
terms of interference. 802.11a operates in unlicensed bands in exactly the same way as 802.11b
and earlier 900 MHz systems operate in unlicensed bands. That is, there are no restrictions on the
types of devices that operate in these bands provided that they all conform to a common set of
rules. Although not a common occurance, one could find a wireless camera, or another device
using the same frequency (channel). Changing channels usually resolves interference issues.
5.1 Possible Interference from the devices in the same band
Although the 5 GHz band is less crowded than 2.4 GHz band, over time, it is possible the 5GHz
band could become equally crowded with interference-causing devices.
The 5 GHz frequency (5725-5875 MHz) can (in theory) contain emissions from microwave ovens,
heaters, plywood laminators, medical diathermy and other non-communications devices. The FCC
allocated 5725-5875 MHz spectrum for UNII (unlicensed) usage as these very high frequencies
have a limited range and generally require line of sight, therefore; these frequencies tend to have low
interference properties. However the user must be aware that a commercial application nearby (for
example, a 10 Kilowatt Microwave oven for drying potato chips or paint) or other interference
causing electronic device nearby could disrupt communications use of that band.
Potential Interference from the bands surrounding UNII-3 band
There are many frequency bands which surround the UNII-3 band (5.725-5.825 GHz) used by
the 1400 series wireless Bridge. Should you encounter severe interference, It may be necessary to
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