10 May 2010

DK7FC's 8.97kHz VLF grabber active antenna

DK7FC runs a grabber on 8.97kHz so he can monitor signals testing on this VLF frequency. He feeds the signal from this active antenna into his PC's soundcard. This is a sketch of the schematic that Stefan posted on the LF reflector today. He has since added some additional C between the drain and ground to reduce the intermod products from LW/MW broadcasters that otherwise produce a strong line on 9kHz.

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