B.2.5 antenna gain, B.2.6 receiver sensitivity, B.2.5 – Campbell Scientific RF401A-Series Spread Spectrum Radios User Manual
Page 42: B.2.6

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