T he structure of «Cyclon» ionosonde controller is described, that allows to increase accuracy determination of virtual height (down to 500 m). Controller consists of two boards: a development (kit) board (with placed CPLD) and the additional board designed by us. Two boards allow to create fast a simple and a low cost controller connected to PCI bus with the timescale synchronized to GPS or UTC time and one reference generator to clock on the all frequency-dependent components.