HN-591
Guidelines for Reducing Interference
Introduction
The transceivers share the same frequency spectrum with other services and other
Part 15 devices in the US. Because of this, you may not achieve 100 percent error free
communications in a given location. You should also expect some level of
interference. However, the flexible design of the radio and the hopping pattern should
allow for adequate performance as long as care is taken in choosing station location,
configuration parameters of the transceivers, and protocols techniques.
Use the following guidelines to reduce interference in your HopNet system.
Guidelines for Selecting Your Site
Use these guidelines to select a proper site for the master remote stations. Suitable
sites must provide the following:
•
An adequate and stable source of primary power.
•
Antenna location that provides an unobstructed transmission path in the direction of
the associated units.
•
Proper antenna selection, data access, and feedline cabling
Guidelines for Avoiding Terrain Obstructions
The HopNet transceivers operate in the 900MHz frequency band. While this band
offers many advantages, it is prone to signal attenuation from obstructions such as
terrain, foliage, buildings and anything else in the transmission path.
Use the following guidelines to avoid terrain obstructions:
•
A line-of-sight transmission path between the base and the associated remote sites
provides for the most reliable transmission path.
•
A line-of-sight path can be achieved by mounting the station antenna on a tower or
elevated structure that raises it to a sufficient level to clear surrounding terrain and
other obstructions.
•
The importance of a clear transmission path relates closely to the distance to be
covered. If the system is to cover only a limited geographical area such as 1-3
miles, then some obstructions may be tolerated with minimal impact.
•
For longer-range systems, any substantial obstruction in the transmission path
could compromise the performance of the system.
©
2000- 2004 Cirronet
™
Inc
34
M-910-0012
Rev
A
