ADTRAN 5045 system manual Path Loss LP, Typical Coaxial Loss for Common Cable Types

TRACER 5045 System Manual Section 2 Microwave Path Engineering Basics

Table 2 gives typical loss figures for some of the more common coaxial cable types (per 100 feet).

Table 2. Typical Coaxial Loss for Common Cable Types

	5.8 GHz Loss/100 ft.
Cable Type	(in dB)
RG58	N/A
RG8 (air)	N/A
RG8 (foam)	N/A
1/4” Coax	11.36
3/8” Coax	9.65
1/2” Coax	6.49
5/8” Coax	4.90
7/8” Coax	N/A
1 1/4” Coax	N/A
1 5/8” Coax	N/A
5.8 GHz Elliptical Waveguide	1.23

Path Loss (LP)

Path loss is the estimated attenuation between the transmit and receive antennas caused by signal separation and scattering. The path loss is considered basic transmission loss over the microwave link. The following expression calculates path loss:

LP =		4πd	2	=		4πdf	2	(dB)
		---------λ 				-----------c

where

fcarrier frequency (Hz)

λcarrier wavelength (c / f) (meters) d path distance (meters)

c speed of light, free-space (meters)

or

LP = 96.6 + 20 ⋅ log10(d) + 20·log10(f) (dB)

where d is expressed in miles and f in GHz

Path loss, as shown here, increases rapidly as either the path length increases or the carrier wavelength decreases (which happens as the carrier frequency increases). Therefore, longer microwave paths naturally experience more path loss than shorter paths. Likewise, higher frequency microwave communication experiences more path loss than lower frequency microwave communication.

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