Microhard Systems MHX-900, Operating Manual

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MHX-900 Operating Manual: Chapter 3 Configuration Options
15
Test the communications
link using a low power level
and work upward. Avoid
using a higher power than
necessary since performance
may actually degrade.
S Register 108 - Output Power Level
The Output Power Level determines at what power the MHX-900 transmits.
The super-sensitive MHX-900 can operate with very low power levels, so it
is recommended that the lowest power necessary is used; using excessive
power contributes to unnecessary “RF pollution”.
The allowable settings are:
* 1 1 mW
2 10 mW
3 100 mW
4 1000 mW
Ideally, you should test the communications performance between units
starting from a low power level and working upward until the RSSI is
sufficiently high and a reliable link is established. Although the conditions
will vary widely between applications, typical uses for each setting are
described below:
Power Use
1 mW For in-building use, typically provides a link up to 300 feet on the
same floor or up/down a level. Outdoors, distances of 10 km can be
achieved if high-gain (directional) antennas are placed high above
ground level and are in direct line-of-sight.
10 mW 200-500 ft indoors, 8-15 km outdoors.
100 mW 400-800 ft indoors, 15-25 km outdoors.
1000 mW
(1 W)
Typically provides communications up to a distance of 1000 feet or
more in-building on the same floor or up/down a few levels,
depending on building construction (wood, concrete, steel, etc.). In
ideal line-of-sight conditions, up to 30 km or more can be achieved.
Note that only an antenna with a gain of no more 6 dBi may be used.
Any higher is a violation of FCC rules. See IMPORTANT warning
below.
IMPORTANT:
FCC and Industry Canada Regulations allow up to 36 dBi effective
radiated power (ERP). Therefore, the sum of the transmitted power (in
dBm), the cabling loss and the antenna gain cannot exceed 36 dBi.
1 mW = 0 dBm
10 mW = 10 dBm
100 mW = 20 dBm
1000 mW = 30 dBm
For example, when transmitting 1 Watt (30 dBm), with cabling losses of
2 dB, the antenna gain cannot exceed 36 - 30 + 2 = 8 dBi. If an antenna
with a gain higher than 8 dBi were to be used, the power setting must
be adjusted appropriately.
Violation of FCC or IC regulations can result in severe fines. It is
the responsibility of the user to understand and ensure compliance
with these regulations.