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![]() Tam/WB2TT wrote: "Owen" wrote in message ... ............................. I do note that my ARRL Antenna Handbook (18th edition) and ARRL Handbook (2000) both use rho, however they reckon that rho=(Za-Zo*)/(Za+Zo) (where Zo* means the conjugate of Zo). They do this without derivation, and seem to be in conflict with the derivation in most texts. I suppose the derivation is buried in some article in QST and in the members only section of the ARRL website. Owen, There was a big discussion about this last year, and somebody posted that the ARRL was going to eliminate the conjugate reference. Les Besser agrees with the ARRL Handbook except he uses gamma for the complex reflection coefficient: gamma=(Za-Zo*)/(Za+Zo) (where Zo* means the conjugate of Zo) But for most practical calculations, the Zo is assumed to be purely real, so many texts give gamma=(Za-Zo)/(Za-Zo). rho=[gamma]=absolute value of gamma=magnitude of gamma Rho can never be greater than one going into a passive network. Only when you have an active device, or gain, can you move outside of the unity circle on the Smith Chart. Slick Tam/WB2TT Back to notation, accepting that the preferred pronumeral for the voltage reflection coefficient is rho, is there a pronumeral used for abs(rho)? Owen |