GE GFK-2489 user manual Feedlines, Feet Cable Type 05 m 15.24 m 30.48 m 152.4 m

6

Feedlines

The choice of feedline used with the antenna should be carefully considered. Poor-quality coaxial cables should be avoided, as they degrade both transmission and reception. The cable should be kept as short as possible to minimize signal loss.

For 900 MHz systems with cable runs of less than 20 ft./6m, an inexpensive cable type such as Type RG-8A/U may be acceptable. For longer runs, or for 2400 MHz systems, we recommend using a low-loss cable type such as Andrew Corp. HELIAX® cable.

The choice of cable depends on the required length, cost considerations, and the amount of signal loss that can be tolerated. The table below lists several types of popular feedlines and indicates the signal losses (in dB) that result when using various lengths of cable at 900 MHz.

	10 Feet	50 Feet	100 Feet	500 Feet
Cable Type	(3.05 m)	(15.24 m)	(30.48 m)	(152.4 m)
LMR-400	0.39 dB	1.95 dB	3.90 dB	Unacceptable Loss
1/2 inch HELIAX	0.23 dB	1.15 dB	2.29 dB	11.45 dB
7/8 inch HELIAX	0.13 dB	0.64 dB	1.28 dB	6.40 dB
1-1/4 inch HELIAX	0.10 dB	0.48 dB	0.95 dB	4.75 dB
1-5/8 inch HELIAX	0.08 dB	0.40 dB	0.80 dB	4.00 dB

. The next table shows the same data for 2400 MHz systems.

	10 Feet	50 Feet	100 Feet	500 Feet
Cable Type	(3.05 m)	(15.24 m)	(30.48 m)	(152.4 m)
LMR-400	0.70 dB	3.50 dB	6.61 dB	Unacceptable Loss
1/2 inch HELIAX	0.35 dB	1.73 dB	3.46 dB	17.3 dB
7/8 inch HELIAX	0.20 dB	0.99 dB	1.97 dB	9.85 dB
1-1/4 inch HELIAX	0.15 dB	0.73 dB	1.45 dB	7.50 dB 1
-5/8 inch HELIAX	0.13 dB	0.63 dB	1.25 dB	6.25 dB

GFK-2489 Chapter 6 Installation 6-9