Soft Rock 40 - V5 First Look


V5 of the Soft Rock 40 is Tony Parks' (KB9YIG) latest rendition of a small QSD based Software Defined Radio. This version of the radio is split into two boards, one with all the frequency dependent components and one with the QSD, LNA and comparators to drive the QSD. The frequency dependent board has the input filter, oscillator and phase shift network. The oscillator is run at the frequency to be received and the phase shift network is used to generate the quadrature clocks needed for the QSD.

Some Pictures

Below is my build of SR 40 V5 S/N #2. I've joined the boards together with 90 degree headers, so one board is upside down from the other. The boards are designed to be mounted one on top of the other, but this arrangement makes debugging and tracing a bit easier, and more importantly I had the 90 degree headers on hand.

Below is the bottom of the frequcny dependent board and the top of the main board.

Below is the bottom of the main board and the top of the frequency dependent board.

Does it work?

V5 seems to be work quite well. Seems as sensitive as V4 and being able to run with an oscillator at the frequency of interest is a big plus. The phase shift network seems to work well, Rocky's IQ correction showed only a minor correction across the band

V5 looks good so far. Now to build up a DDS top board to make it a bit more frequency agile....

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Last Updated 4 November 2005

Copyright © Bill Tracey 2005