GE Reason RT430 Technical Manual page 97

APPENDIX E - GPS ANTENNA DELAY COMPENSATION
The antenna cable affects the unit's performance in two different ways: GPS signal attenuation and GPS
signal propagation delay.
GPS Signal Attenuation
GPS signal attenuation is related to cable type and overall cable length. When using the active antenna
supplied by Alstom, total attenuation should not exceed 32 dB.
Total attenuation can be computed by using:
Where is the attenuation per unit length for the given cable and is the overall cable length.
The table below shows a few typical cable configurations and the associated total attenuation.
TABLE D.1: Antenna cables attenuation.
Cable length
m (50 ft)
m (82 ft)
m (164 ft)
m (246 ft)
m (328 ft)
m (410 ft)
m (492 ft)
Propagation Delay
RT430-TM-EN-5
Cable RGC58
—
7 dB
—
12 dB
—
23 dB
—
12 dB
—
17 dB
—
21 dB
—
25 dB
Cable RGC8
RT430
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