Man, it's been far too long since I last posted. I've been working hard on automating my 12-20m magloop antenna and already have the variable capacitor remote control and position sensor working. Next up: remote control for the transformer feed so I can have it automatically configure itself based on a requested frequency!

I spent a few days earlier this week struggling with transistors, but it ended up being worthwhile since I learned a lot. For example, an n-type MOSFET will only allow voltages that are up to the gate voltage across, which means that it really needs to be on the ground side of whatever component is being controlled. You can see the behavior here (with BJTs for comparison):

The bottom right circuit in the above diagram matches how I eventually successfully used the 2N7000 MOSFETs to control the RF relay in the video here:

This project also had me working on my first PCB design in KiCAD, since there was no way I was going to do all that fiddly soldering of these SMD relays to through-hole perf board multiple times!

Now to wait for PCBway to get back to me…

#AmateurRadio #HamRadio #electronics #kicad #PCB #circuit #maker