Thursday, March 18, 2010

600m Transverter

The plan has been around for a while, ah well, since January, to build a transverter or at least a TX converter for HF to MF. Some ideas came along, some back a forth struggle, but finally, I soldered some components together. I have to admit, this design is not yet (!) tested.

This resembles a regular XOR Pierce crystal oscillator with an additional XOR for pulse shaping. As "filter and matching network", a second crystal is used. The drive level for the subharmonic mixer is adjusted by R3.
CR1 is a ceramic resonator for 500kHz. One could image to arrange a capacitors in series with it in order to pull up the resonator's response slightly.
In my junk box, there seems no indication for a 28.5MHz crystal, therefore, I consider using a regular LC resonant circuit, which is not yet figured out however.