Separation of Simultaneous WWV and WWVH Signal Components for Ionospheric Doppler Analyses

The carriers of WWV and WWVH are used for HF skywave ionospheric research. Both undergo Doppler shifts in response to changing solar radiation on the ionosphere that depends on the actual path from transmitter to receiver. There are many times when a receive location can receive both WWV and WWVH simultaneously. Because they are precisely on the same frequency their spectra overlap making it difficult to impossible to discern which spectral contributions belong to which carrier. However WWV and WWVH both transmit audio sidetones in an interlaced schedule in which tone assignment changes every minute. This paper describes spectral separation accomplished through a deinterlace process using two receivers and two spectrographs.