I am working on a novel design for a 70MHz transverter. It uses a diode ring mixer as a bilateral parametric up-downconverter. This unusual method has some advantages. For example I think that I can build a complete transverter with just three transistors. These are configured as a charge pump (aka high power crystal controlled oscillator). The Pump drives the diode ring in such a way that it makes the diodes work as varactors. This allows the mixer to work as a parametric amplifier. This reduces loss and improves noise figure. This is critical as the mixer is used for both up and down conversion. Another plus of this odd system is that no antenna change over is required due to the bilaterallity of the mixer. I have only seen this done once before. So far I have the charge pump working. This uses a cheap 20MHz crystal which will allow me to transvert from 50MHz.