SA2CLC radio stuff

  PCBway – Part 2: Useful, simple things you’ll actually use Here is part 2 of the PCBway board order. As stated in the previous post, I made several boards. Simple does not mean stupid. I realized that I sometimes spend a lot of time building the same things over and over when building or restoring old electronics, so I when Emily at PCBway got in touch with me, I made a few boards that could ease my future repairs and restorations. Universal rectifier boards Universal rectifier boards and the components they replaced First up: rectifier boards. I build and repair a lot of equipment, both high voltage stuff, and lower <24 V. A lot of older gear contains selenium rectifiers, which I like to replace with silicon. So instead of hacking together diode bridges in mid-air every time, I designed two universal rectifier PCB's. The larger is stackable, or rather possible to series connect to increase voltage handling, up to 1800V for two boards. The smaller board is just a full wave rec...

 I needed to knock down the second harmonic from my amplifier as I was getting spotted on 20 when conditions were good, when calling CQ on 40 using my multiband vertical. At first I was thinking about some sort of low impedance, series resonant circuit on 20, installed between vertical feedpoint and ground, but then I shifted to coax stubs, but I had no SO239 tee's. I wanted to it done right away so I figured I'd install panel mount SO239's on an aluminum box, and make the stub connection on the inside, when I read about W2VJN's hybrid lowpass filter. It's a three pole lowpass, but instead of capacitors, it uses coaxial cables with their ends open. Since they need to be left open, they are cut to 1/4 wave on the frequency that we want to supress. For 20M, this works out to be approx 3,4M.  The series coil is about 1uH to resonate with the coax capacitance. I built this because it was an easy design, and no more work than to drill 4 holes in a 1590B box. I used, afte...