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Figure 3: Bad line of sight
Step 2: Finding suitable antenna site
A suitable antenna site requires an unobstructed view to the AIR base station, a stable
antenna mounting surface, a distance for power supply max 20m of coax cable. Examples
are shown on figures below.
antenna mounting surface, a distance for power supply max 20m of coax cable. Examples
are shown on figures below.
Caution
It is important to estimate the cable length at this point.
Maximum distance for power supply is not more than 20m of coax cable. In case of more
cable mount a separate power inserter and power supply unit on the coax cable in the
distance of 20m or less to the transceiver.
cable mount a separate power inserter and power supply unit on the coax cable in the
distance of 20m or less to the transceiver.
The max distance of the coax cable, without the usage of a house amplifier, from the Cable
modem to the Power inserter can be calculated with this formula:
modem to the Power inserter can be calculated with this formula:
Signal level received at the Power inserter – loss of the splitter (if applicable) – cable and
connector loss from Power inserter to Modem >-81dBm
connector loss from Power inserter to Modem >-81dBm
Example:
-67 - 6,2 - 7,2(30mcable) = -80,4dBm in this case there should be theoretically enough
signal without the usage of a home amplifier
-67 - 6,2 - 7,2(30mcable) = -80,4dBm in this case there should be theoretically enough
signal without the usage of a home amplifier
Caution
Minimum receive level from the AIR CPE for QAM64 is -81dBm
A typical power inserter has an attenuation under 1 dB.
A typical power inserter has an attenuation under 1 dB.