Page 67 of 82 Revision No.: 1.5
other heavy construction will inhibit signals more than light obstacles such as a few
trees or a simple post. When trying to increase the range, several factors including
antenna height, frequency, antenna type and power output when all should be
considered.
Antenna height allows the signal to travel above obstacles and also reduce any
interference from the ground. Lower frequencies travel further than higher
frequencies, and directional antennas can focus energy, thereby increasing range in
fixed installations.
6. Long cable: In general, it is best to keep the RF cable as short as possible. All
cables have losses which are usually measured in dB loss per 100 ft. Some
common cables and dB losses are included in Table 5.
Table 5: Potential Signal Strength Loss due to Antenna Cable Length
As a summary, note the following:
Factors that determine RF link range:
• Ambient RF noise (interference)
• Line-of-sight obstructions
• Transmit power
• Receive sensitivity
• Antenna configuration
Factors that affect antenna performance:
• RF cable length
• Height of antennas off the ground
• Obstructions
• Radiation pattern
• Antenna Gain
Cable Type Loss at 900
MHz per 100'
(loss per
100m)
Loss at 904
GHz per 100'
(loss per
100m)
Diameter
Inches (mm)
RG-58 14.5 (47.4)dB 25.3 (83.2)dB 0.195 (4.95)dB
RG-174 25.9 (85.0)dB 44.4
(145.84)dB
0.100 (2.54)dB
RG-316 24.7 (81.0)dB 42.4 (139.0)dB 0.102 (2.59)dB
LMR-195 11.1 (36.5)dB 19.0 (62.4)dB 0.195 (4.95)dB
LMR-240 7.6 (24.8)dB 12.9 (42.4)dB 0.240 (6.10)dB
LMR-600 2.5 (8.2)dB 4.4 (14.5)dB 0.590
(14.99)dB
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