The 40/80 Dual gate first mixer - crystal filter - DBM detector

Dual Gate mixer - Xtal filter - Dual Gate IF

Dual Gate IF - Logic Gate Xtal controlled oscillator - Dual gate oscillator buffer. DBM detector.

The antenna fed a hi/lo bandpass filter. The VFO fed the first mixer which fed the Xtal oscillator. By switching the antenna selector the same VFO worked with 40 and 80 meters.

We used both the Dual Gate mixer and the DBM. The DBM requires a large signal so we used it after getting so signal gain in the amps.