Sensitivity of HF circuit simulations to electron density models

The dependence of HF propagation parameters on the form of the electron density model used in circuit simulation calculations is investigated. It is seen that for identical values of the F₂ region critical frequency and maximum height, no one of the selected models consistently reproduces observed electron density profiles better than any other. The differences in HF circuit parameters resulting from the use of different electron density models are seen to be significantly less than the uncertainty in the simulated parameters that arises from the inability to specify or predict the ionospheric structure with perfect accuracy.