ADTRAN 6000 Series system manual Receiver Power

TRACER 6000 Series Integrated System Manual		Section 2 Microwave Path Engineering Basics
where the variables in the equations are defined as
PR	received power (dBm)
Psens	receiver sensitivity (dBm)
PT	transmitted power (adjustable up to 20, 24, or 27 dBm maximum – depending on product)
GT	transmit antenna gain (decibels referenced to an isotropic source – dBi)
GR	receive antenna gain (dBi)

Lother losses (RF coaxial cable, etc. – dB)

LP path loss (dB)

Higher levels of fade margin indicate stronger protection against signal fading and a more reliable link. For most applications, 20 to 30 dB of fade margin should ensure a reliable link. ADTRAN provides a free wireless link planner tool on the ADTRAN website (www.adtran.com – see Service/Support > Technical Support > TRACER Products).

The following sections further discuss the necessary power calculations and their components.

4.RECEIVER POWER

The viability of a particular microwave path is determined by the power of the transmitted microwave signal, the transmit and receive antenna gain, distance, and accumulated system losses (such as RF coaxial cable losses and path loss).

The equation relating received signal power to the other microwave parameters is

	P		PTGTGRλ2	(watts, W)
		R	= ------------------------------
			(4π)2d2L
or (in decibel notation)
	PR = PT + GT + GR - L - LP			(decibels referenced to a milliwatt, dBm)
where the variables in the equations are defined as
PR	received power (dBm)
PT	transmitted power (adjustable up to 20, 24, or 27 dBm maximum – depending on product)
GT	transmit antenna gain (decibels referenced to an isotropic source – dBi)
GR	receive antenna gain (dBi)

λcarrier wavelength (meters)

dpath distance (meters)

Lother losses (RF coaxial cable, etc. – dB)

LP path loss (dB)

When using decibel notation, all quantities must be individually converted to decibels prior to performing addition and subtraction.

612806420L1-1F Copyright © 2005 ADTRAN, Inc. 17