A Word About Radio Interference - Microwave Data Systems MDS 9810 Installation And Operation Manual

10 MDS 9810 Installation and Operation Guide
With the hand-held antenna positioned near the proposed mounting
spot, a technician can check for synchronization with the master station
(shown by a lit lamp on the front panel) and measure the reported
SYNC
RSSI value. If adequate signal strength cannot be obtained, it may be
necessary to mount the station antennas higher, use higher gain
antennas, or select a different site. To prepare the equipment for an
on-the-air test, follow the general installation procedures given in this
guide and become familiar with the operating instructions given in Sec-
tion 5.0, beginning on Page 26.
If time is short, and a site survey is impractical, a computer path study
is a good alternative. Factors such as terrain, distance, transmitter
power, receiver sensitivity, and other conditions are taken into account
to predict the performance of a proposed system. Contact MDS for more
information on path study services.

3.3 A Word About Radio Interference

The transceiver shares frequency spectrums with other services and
other Part 15 (unlicensed) devices in the USA. As such, near 100% error
free communications may not be achieved in a given location, and some
level of interference should be expected. However, the radio's flexible
design and hopping techniques should allow adequate performance as
long as care is taken in choosing station location, configuration of radio
parameters and software/protocol techniques.
In general, keep the following points in mind when setting up your com-
munications network:
1. Systems installed in rural areas are least likely to encounter
interference; those in suburban and urban environments are more
likely to be affected by other devices operating in the license-free
frequency band and by adjacent licensed services.
2. If possible, use a directional antenna at remote sites. Although these
antennas may be more costly than omnidirectional types, they con-
fine the transmission and reception pattern to a comparatively nar-
row lobe, which minimizes interference to (and from) stations
located outside the pattern. (The use of a directional antenna may
not be possible in a simplex peer-to-peer network, where all remotes
are designed to communicate with one another.)
3. If interference is suspected from a nearby licensed system (such as a
paging transmitter), it may be helpful to use horizontal polarization
of all antennas in the network. Because most other services use ver-
tical polarization in this band, an additional 20 dB of attenuation to
interference can be achieved by using horizontal polarization.
MDS 05-3301A01, Rev. C