The april 'TT' revealed the pioneering work of Harold Wilson, G30GW, in developing a polyphase SSB/CW detector for use in an experimental direct-conversion receiver, reviewing the background to this form of four-path phasing detectororiginallyinvented by Michael Gingell (STL) in 1973. It also discussed the advantages of this approach compared with the conventional two-phase phasing detector, as described by Dr RCV Macario, GW8SRW, in 1980. It further reported that G3OGW was planning an improved polyphase D-Czero-IF receiver using the latest IC devices in the front-end. Even before the publication of the April issue, a further report arrived from G3OGW that underlines that this approach opens the way to a high-performance, low-cost receiver (and potentially to a four-path HF transceiver). He writes: "I have now taken the further step I proposed by combining the Tayloe quadrature switching mixer, using the FST3253, with the four-path audio phas inq system, as shown in Fig 1.
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