Back on the Airwaves: The Mint-Tin 20m CW Transceiver Project
We’re back, baby! And what better way to mark a ‘return’ than by jumping headfirst into a new project? This time, I’m attempting to build a miniature CW transceiver for 20m—something compact, efficient, and powerful enough to make real contacts. The goal? Fit the entire thing into a mint tin.
It’s an ambitious little build, but I like a challenge. There’s something exciting about taking a handful of components and making them do something real—turning theory into a physical, working radio. I could just buy a QRP kit and solder it together, but where’s the fun in that? If I want the “ultimate” portable CW transceiver, I have to make it myself.
The Plan: Tiny But Mighty
The idea here isn’t to just bodge together some components on perfboard and call it a day. This time, I’m going all-in on designing a proper PCB—laying out traces, optimizing the circuit, and ensuring it all fits into the smallest possible footprint without compromising performance.
At its core, this transceiver will use a NE602 mixer, a workhorse IC found in countless homebrew receivers and small transmitters. For the final amplifier, I’m going with BS170 MOSFETs, which should get me about 3W output at 12V, pulling around 1A of current at full power. Not a lot, but with CW, it’s enough to be heard.
For tuning, I’m using an Si5351A VFO, providing rock-solid frequency stability and allowing for precise tuning. No more drifting off-frequency after 10 minutes of operation! I’m also including a small LED display to show the operating frequency, because while old-school analog dials are cool, I want something practical for portable use.
Why a Mint Tin?
Because it’s fun. There’s something oddly satisfying about cramming a full transceiver into a tiny space, and a mint tin just feels right—like a challenge that begs to be tackled. Plus, there’s a long tradition of “Altoids tin radios” in the QRP community, and I like the idea of carrying a fully functional HF rig in my pocket.
Powering It Up: The 12V Solution
One key requirement for this build is power flexibility. I don’t want to be tied to a bench power supply or a bulky battery pack. Fortunately, I already have a USB power bank that I use for other projects, and it’s the perfect match for this transceiver. Being able to run directly off a USB-C PD to 12V adapter means I can operate just about anywhere—POTA-style without the full POTA setup.
The Learning Curve
This project is pushing me into new territory, especially with PCB design. I’ve been learning KiCad to turn my circuits into real, manufacturable PCBs, and I’m already seeing how much better it is than my old “rats nest of wires” approach. Being able to visualize the board layout before fabrication is a game-changer.
It’s another skill that’ll help me in future projects. Every new thing I learn is an investment in what I’ll be able to do later. But that doesn’t mean I’m just grinding skills for some distant future—I’m enjoying the process now. There’s something incredibly satisfying about designing something from scratch and watching it come to life.
What’s Next?
The next steps are finalizing the PCB design, running some simulations, and then actually getting the boards made. To start, I will prototype by etching my own boards, before then getting some PCBs made. Either way, I want to take this from concept to working transceiver as efficiently as possible.
There’s nothing quite like getting a homebrew radio on the air for the first time. And if all goes well, I’ll be calling CQ on 20m soon—from a transceiver I built myself, packed neatly into a mint tin. Now that’s the dream.