LF and VLF antenna modeling

The 60 kHz timing station in Fort Collins, Colorado known as WWVB and a 21.4 kHz Navy VLF transmit antenna at Lualualei, Hawaii were modeled using the method of moments wire modeling code, Expert MININEC Broadcast Professional. An accurate computational antenna model was needed in order to evaluate proposed antenna modifications. The evaluation criteria for defining an "accurate" computational antenna model were accurate prediction of measured values for feed impedance, effective height, and self-resonant frequency.