The aim of this work is development of algorithm for evaluation of transfer function in power line communication (PLC) channel with narrowband orthogonal frequency division multiplexing (OFDM) signal modulation using convenient user interface. This algorithm can be used while planning PLC system. There were explored long line and parametric model of power line. Assuming similarity of wireless and power line communication the influence of multipath on line impedance was investigated. It was shown that signal amplitude is Ricean distributed. The coefficients for this variance distribution were derived from the attenuation parametric modeling. For simulation LabView program interface was chosen. The developed algorithm permits evaluation of maximal distance between receiver and transmitter that doesn’t require repeater installation.