Campbell Scientific RF401A-Series Spread Spectrum Radios - Manual (Page 42)

Appendix B. Distance vs. Antenna Gain, Terrain, and Other Factors
TABLE B-3. Cable Loss
Cable Type Outside Diameter Loss (dB/100 ft) @ 900 MHz
RG-58A/U 0.195” 21.1
COAX RPSMA-L 0.195” 11.1
RG-8 0.405” 6.9
COAX NTN-L 0.405” 4.5
LMR-400 0.405” 3.9
*CSI stocked antenna cables are shaded.
CSI’s “COAX RPSMA-L” uses LMR-195 antenna cable. Cable loss is
proportional to length as the following table illustrates.
TABLE B-4. LMR-195 Cable Loss vs. Length @ 900 MHz
LENGTH (ft.) LOSS (dB)
100 11.1
50 5.6
25 2.8
10 1.1
6 0.7
B.2.5 Antenna Gain
Antenna gain is specified either in dBi (decibels of gain relative to an isotropic
radiator) or in dBd (decibels of gain relative to a dipole). The relationship is:
dBi = dBd + 2.15
Some antennas that are FCC approved for use with the RF401A series are:
TABLE B-5. Antenna Gain of Recommended Antennas
Mfg. Antenna Type Band Model
CSI Part
Number
dBd
Gain
dBi
Gain Size
Astron Omni (1/2 wave) 900 MHz AXH900 RP SMA R 14204 0 2.15 6.75 in
Antenex Collinear 900 MHz FG9023 14221 3 5.15 24 in
MaxRad Yagi 900 MHz BMOY8905 14201 9 11.15 21.4 in
B.2.6 Receiver Sensitivity
Receiver sensitivity is usually specified in dBm for a specific bit error rate
(BER). The transceiver module used in the RF401A series is specified at –109
dBm at ~10 –4 raw BER.
B-4