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Transmission Path Calculation
(1) Transmitter Output Power:
Antenna Gain
(4) Free Space Loss: (= 32.4+20 log f + 20 log d), f/MHz, d/km
(5) Calculated Received Signal Level: (1) + (2) + (3) – (4) =
(6) Measured Received Signal Level =
Difference: (6) – (5) =
BroadOne GX4000 Manual (R3.0) issue 1.03
3.3V
3.0V
2.0V
1.0V
0 V
-55 dBm
Figure 3.5 Typical RSL Chart
Once the antenna is set at peak level, tighten all adjustments and
mounting hardware. Continue to monitor the RSL while doing this to
ensure final tightening of the hardware has little to no effect on RSL.
The calculated receive signal strength should always be attained or
exceeded. Repeat the procedure at both ends of the link until the
calculated RSL is achieved. If the RSL is worse than the calculated value
beyond +/- 2 dB after the above procedures, do the trouble shooting.
A lower than expected RSL is a defective transmission line or an
obstructed path. Verify that calculated insertion loss through the
transmission line is within limits and replace antennas or transmission
system elements with known good devices until the fault is found.
Parameter
(2) TX side:
(3) RX side:
dB
Where:
Transmitter output power:
Center frequency:
Antenna gain:
-45 dBm
-35 dBm
dBm
0 to +10 dBm for 70/80 GHz band
73,503 MHz for 70 GHz band
83,494 MHz for 80 GHz band
43 dB for 1-feet (30 cm) antenna
48 dB for 2-feet (60 cm) antenna
Commissioning Test
-25 dBm
Loss/Gain in dB
dBm
dB
dB
dB
dBm
3-5
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