Alan - K6ZY at the last Puget Sound QRP (pQRP) meeting mentioned he was considering building a Homebrew Farhan VU2ESE Minima Transceiver project. After looking at the schematic for the Mimina, it appears that the Mixer Circuit would work very nicely as an stand-alone mixer for my experimental use. Very good documentation of the mixer's operation is provided by Farhan. The mixer used in the Minima has been dubbed the “KISS Mixer” by Chris Trask in his paper.
|Minima Mixer Circuit in LTSpice|
So far I have not gleamed much information from the LTSpice simulation, but maybe I have something wrong with my circuit; bias, configuration, signal levels or expected output. Or, maybe LTSpice can not deal with mixed signals correctly, but I will continue working with LTSpice to learn more.
In preparation for my experiment and use of the Mixer Circuit, I have started the initial design of a PCB using DipTrace. Keeping with my ever present Goal of building electronic projects as small as I can, this initial design is larger than I think the final design will be, as I have currently configured it to used larger components than necessary. I think I can find small SOT-23 J310 JFET packages and smaller transformer cores. But this is a start.
|Mixer Layout in DipTrace|
This mixer as a stand-alone device will be very useful in my electronics shop - Thanks Farhan.