QCX-mini? Didn’t You Just Finish A QMX+?
Sometimes, things get shuffled around and end up on the back burner for a really, really long time. Embarassingly long.
Back in January of 2022, I was embarking on my CW journey. I was also looking for a kit to build. The QRP Labs QCX-mini looked like exactly the thing to pick up. So in August of 2022, I ordered one and it arrived on my doorstep. I waited a couple of weeks and then got started. I made really good progress getting to the point just before installing the toroids for the low pass filter.
And then…
It was put on the back of the bench.
It sat in a little plastic box with all of its parts. Waiting. Watching me assemble my failed QMX. Then my successful QMX+. It watched repairs and experiments and didn’t say a thing. Until this week.
Why?
I have two dogs wandering the house in cones of shame. My beagle has an issue with his paw and really needs to stop licking it and our Rottie just had surgery on her hind leg. She is drugged out of her mind and a bit incontinent. That makes leaving the house a bad idea. So as I was poking around in the basement for a component, I noticed the QCX-mini and thought, “Well, I wonder where I left off.” With both dogs sleeping on the floor in my office where I could monitor them, I decided to finish it up.
Embarrassingly, it was roughly two hours of work getting what little was left together and buttoned up.
Side Story
See that hemostat in the picture? It’s one of the most useful tools on my bench. I have big hands and it makes working with small components difficult sometimes. Having that pair around allows me to manipluate things with a bit more dexterity. But that particular tool has a story.
Back a number of years ago, my wife and I were framing a room in our basement. We were getting to the end of the day and I was drilling holes into metal studs for screws so we could get the drywall started the next day. I was tired. I was NOT paying attention. Pushing on the stud with my left hand and drilling with the right led to a bit of a tactical blunder and the drill went through my thumb.
Ouch.
It was the kind of injury where you think to yourself, “I could tough it out, but that might also be the dumbest thing to do right now” so it was off to the ER. Going through the metal detector was a blast. I had a box cutter, screws, drill bits, and all kinds of other stuff that I needed to dump while bleeding through the gauze in my hand.
The doctor gave me a couple of stitches and made some small talk. He asked me if I did construction for a living. I laughed. A lot.
No. No I don’t do construction for a living. If I were a professional, I wouldn’t be framing walls on a Saturday and I wouldn’t be in the ER with a hole in my thumb. We got a couple of laughs and he was done. As he was packing up, he picked up the hemostat he didn’t use and tucked it into my shirt pocket through the pencil hole. He said I might find a use for it. (It would have to be thrown away otherwise.) Boy, he was right!
Enough Nonsense. What About The Radio?
Since I’ve been running my QMX+ on my desk as a WSPR beacon, I had the power supply, cable, and antenna all ready to go. I applied power and…the display was a solid bright yellow block. Sigh. One the one hand, I had a light! On the other, the display was blank.
Oh. Wait. The trim pot right next to the display might do something. It does. It sets the contrast and suddenly there was text. I hit the reset button and set it up for 20-meters. I got the paddles set and plugged in my Anker portable speaker. And seriously? Shout out to Thomas K4SWL for sharing that speaker with the world. It’s fantastic! I use it with my radios and with my phone when I’m out on the porch and want to hear some tunes. It’s a great speaker!
I spun the dial and heard a station. Then another. The receiver on this thing is great! I decided to key up. With it plugged in to my SWR & Power meter I was reading about 0.1 watt. I called CQ TEST DE KC8JC a couple of times and I was picked up by the Reverse Beacon Network. Not just picked up, but picked up 1600 miles away by VE6JY. I was a bit stunned. From Alberta to South Carolina stations were hearing me. This was really impressive. The power of QRP CW will never cease to amaze.
I watched my SWR & Power meter that the radio was plugged into and thought about the power output. I pushed the power supply up a bit and we topped off at about .25 watts. Interesting. Something didn’t seem quite right.
What About The Test Systems?
I opened up the rig and started to poke at the test programs that are included in the software on the radio. Running a line from the designated spot on the board to the drains on the transistors topped out at about 3 watts at one point. Reading the documentation, this was likely a fault with my low pass filter toroids.
Nice!
Looking at the L2 toroid led to some embarassment. The windings were on top of one another and not very neatly arranged. I pulled it out and rewound it just to put my mind at ease. I re-counted all of my turns on all of the toroids. I checked for continuity. All of the things I could do with the limited test equipment I have were done. Perplexing.
But not perplexing enough for me to call it a failure or for me to pull it apart further. 1600 miles on less than a watt? That kind of sounds like fun to me. Being a self-aware person though, I know that I will open it again. And again. And again.
Final
The interesting thing about a kit of any kind is that it’s done when you decide it’s done. Sure, you can poke at it until it winds up being exactly what the manufacturer says it will or you can take it and make it whatever you want. I’m getting the sense that I’m going to box this rig up knowing that it puts out less than a watt and pull it out when I want to have some REAL fun with QRPp (less than a watt operation). This might also become that project that I pull apart and noodle with now and again when the itch strikes. I think most tinkerers have those projects that get tweaked and retweaked without end because poking at it becomes The Point.
In any case, I was picked up 1600 miles away. That’s wild!
73 and thanks for reading!
