Microwave Data Systems MDS entraNET 2400 Especificaciones descargar pdf (Pagina 118)

110 MDS entraNET 900 System Guide MDS 05-4055A01, Rev. A

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. Use a directional antenna at Remote sites whenever possible.

Although these antennas may be more costly than omnidirectional

types, they conﬁne the transmission and reception pattern to a com-

paratively narrow lobe, that minimizes interference to (and from)

stations located outside the pattern.

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.

Another approach is to use a bandpass ﬁlter to attenuate all signals

outside the 900 MHz band.

4. Multiple Access Point units can co-exist in proximity to each other

with only very minor interference. Each Network Address has a dif-

ferent hop pattern. Additional isolation can be achieved by using

separate directional antennas with as much vertical or horizontal

separation as is practical.

5. If constant interference is present in a particular frequency zone, it

may be necessary to “skip” that zone from the radio’s hopping pat-

tern. The radio includes built-in software to help users identify and

remove blocked frequency zones from its hopping pattern.

(See “Skip Zone Options Menu” on Page 41 for more information.)

6. If interference problems persist even after skipping some zones, try

reducing the length of data streams. Groups of short data streams

have a better chance of getting through in the presence of interfer-

ence than do long streams.

7. The power output of all radios in a system should be set for the low-

est level necessary for reliable communications. This lessens the

chance of causing unnecessary interference to nearby systems.

If you are not familiar with these interference-control techniques, con-

tact your MDS sales or Technical Support Department for more infor-

mation.

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Microwave Data Systems MDS entraNET 2400 Especificaciones Pagina 118