This signal source is a harmonic, or comb generator, which produces a series of strong outputs across the electromagnetic spectrum from VHF to 10GHz. These signals can be used to align receivers and converters or check the radiation pattern of antennas. The kit has just 21 components and can be constructed in about 30 minutes. The PCB has tracks on both sides and now uses plated through holes to pass signals through the PCB. There are a couple of surface mount devices which need careful soldering. (But G3WGM successfully made one!). See http://g0mrf.com/source2.htm
for more details.