Kit Design: Regenerative Shortwave Receiver
During my presidency of the University of Michigan Amateur Radio Club, I tried to schedule at least one workshop-type event per school year, to serve members who wanted hands-on experience with electronics. After discussing ideas for the Winter 2015 topic with individual members, I found that a majority were interested in learning about the function and construction of radio receivers. I eventually chose to populate kits for a circuit designed by Charles Kitchin, N1TEV, “A Simple Regen Radio for Beginners”, published in the September 2000 issue of QST magazine. I chose this specific kit based on its simple construction, the availability of documentation explaining the theory of operation, and because a regenerative circuit operates on principles more easily understood by beginners than a more modern receiver.
After choosing the project, the next step was to gather parts from a number of vendors and lay them as per the schematic. I designed the construction to be “Manhattan Style”, using small pads of copper-clad circuit board material glued to a 4”x5” PCB Backplane. After 5 revisions, I settled on a layout, digitized it, and would later make it available to kit-builders to reference where each component would be placed.
I built two of the kits to test the design. The first was simply to ensure the circuit was in working order. When I built the second I took pictures and notes of every component as it was installed. I compiled that content into a 25-page tutorial outlining the procedure to build the receiver step-by-step. This tutorial, the component layout, the original article from QST, and N1TEV’s theory of operation notes, was handed to each builder.
Over 3 monthly meetings, 15 members gathered to work on the kits. The club and individuals provided soldering irons and other tools needed to complete the build. By the end of second month a few radios were completed and in working order, and I gave a short presentation on how the circuits worked. At the third meeting nearly all attendees had completed and working kits. The radios, designed to receive signals in the area of 7 MHz, could be easily modified to receive lower frequencies as far down as the AM broadcast band.