s the EIRP in dBW? EIRP = 0 dBW - 3 dB + 34 dBi = +31 dBW. Calculation of Isotropic Receive Level (IRL). The IRL is the RF power level impinging on the receive antenna. It would be the power we would measure at the base of an isotropic receive antenna. IRLdBW=EIRPdBw-Path lossdB = (9.6) This calculation is shown graphically in Figure 9.9. Calculation of Receive Signal Level (RSL). The receive signal level (RSL) is the power level at the input port of the first active stage in the receiver. The power level is conven- tionally measured in dBm or dBW. RSLdww = IRLdbW + rec. ant. gain (dB) - rec. trans. line losses (dB). (9.7) (Note: Power levels can be in dBm as well, but we must be consistent.) Antenna Transmission line Transmitter power output Transmitter EIRP = Trans. output (dBW) - Trans. line loss (dB) + Ant. gain (dB) Figure 9.8 Elements in the calculation of EIRP. 5dBi stands for decibels referenced to an isotropic (antenna). CONCEPTS IN TRANSMISSION TRANSPORT EIRPdBW IRLdaw Path loss IRLdbw =EIRPasw-Path lossa - below 10-GHz Path loss = Free-space loss (FSL) Figure 9.9 Calculation of isotropic receive level (IRL). Example. Suppose the IRL was -121 dBW, the receive antenna gain was 31 dB, and the line losses were 5.6 dB. What would the RSL be? RSL = - 121 dBW + 31 dB - 5.6 dB = -95.6 dBW. Calculation of Receiver Noise Level. The thermal noise level of a receiver is a function of the receiver noise figure and its bandwidth. For analog radio systems, receiver thermal noise level is calculated using the bandwidth of the intermediate frequency (IF). For digital systems, the noise level of interest is in only 1 Hz of bandwidth using the notation No, the noise level in a 1-Hz bandwidth. The noise that a device self-generates is given by its noise figure (dB) or a noise tem- perature value. Any device, even passive devices, above absolute zero generates thermal noise. We know the thermal noise power level in a 1-Hz bandwidth of a perfect receiver operating at absolute zero. It is Pn==228.6 dBW/Hz, (9.8) where Pn is 