Thursday 28 March 2024


: a feature-packed, high performance, 5-BAND 5W, CW and Digi-modes transceiver kit, including embedded SDR, 24-bit 48 ksps USB sound card, CAT control, synthesized VFO with TCXO reference.

I am only just starting out on the looooong journey to learn Morse Code and I already have a few radios perfectly capable of transmitting CW, so why purchase a QRP-LABS QMX??

Well apart from the fact that I just love to build kits,  I also have an enormous amount of respect for Hans Summers’ amazing designs. I have already built two of his magnificent QDX Digital Transceiver Kits and they perform so incredibly well. The transmitted signals are so pure and clean and everything just works without any fuss or trouble.

The QMX is no different but in addition to being a first class 5W, 5-Band Digital Transceiver,  it has the added bonus of having CW Mode with built-in keyer and decoder! And the high performance microcontroller provides a pure signal with click-less operation in Full or Semi break-in.

Did I order the self-build kit??  I looked at the Assembly Manual and also read about a lot of the problems that constructors were experiencing and thought that it might be a step too far for me. The QDX kit is relatively simple, but the QMX is definitely not for a beginner like me - for a start  it has a 6-layer PCB which means that any reworks greatly increases the likelihood of PCB damage, so I ordered a pre-assembled unit.

PLEASE NOTE that at the time of writing, there is a SIGNIFICANT WAITING LIST for assembled radios and when you order one, you are placed in the queue. I was at position #630 and they only assemble about 25 per week, which roughly equates to a 6 month wait! 😵

With the assembly fees, an aluminium enclosure and postage to the UK, the final price might seem a little choppy compared to something like a (tr)uSDX (a superb all-rounder), but the QMX is in a different league and is much more ‘focused’.  Although the truSDX performs well with CW (as well as SSB), the fact is, it’s an 8-bit system and is being pushed to its absolute limits all the time. The QMX on the other hand is a very high performance bit of kit with a 24-bit USB soundcard and an embedded SDR receiver.

I decided to cancel my fully assembled
QMX and order a kit instead!

As usual, the supplied (online) construction guide is absolutely first class!! There's no way you could improve on this (except for a couple of generic images) and I'd suggest that you read all the way through it prior to starting your build.  Hans' support has always been excellent, so if you do hit a problem, I'm sure he'll be there to help you one way or another - along with all the fine constructors in the GROUPSIO forum. 

There's probably less than 150 solder-joints to be made in this kit, which seems like nothing to the 800+ of the Radio-Kits Explorer, but I fear this build much more than I did the Explorer.

To avoid spending hours of frustrating trouble-shooting, I'm really going to have to pay attention to this build and use every ounce of my (limited) kit-building experience to avoid silly errors.

The first step (for me) is to read through the manual looking for all those little "warnings" and "cautions" which, if ignored, could lead to big problems. I use a bright orange highlighter pen to make sure that I don't miss them once I start the build.

Another useful thing to do is to put aside components which have "special needs", such as those which are soldered to the underside of the pcb when they could easily be soldered to the upper-side by mistake.

Also worth noting are the necessary mods which are highlighted on the QRP-Labs website such as the potential Q103/Q104 drains short which needs checking before applying power for the first time.

So it's Easter Weekend and that's the perfect time to start the build. I'm off to the caravan tonight (Thursday) for a nice, long weekend and I hope to have finished the kit by the time we head home on Tuesday.

Results to follow...


VE9KK said...

Good morning Tom, an excellent idea to order the kit and cancel the completed rig. It's great fun and a way to pass some time while at the same time you have the joy of operating something you put together. One kit I would suggest if you want a challenge if the Elecraft K2 kit.
Have a great Easter weekend.

MadDogMcQ said...

Hi Mike,
That K2-Kit price is a bit choppy for my wallet, LOL.

Have a great Easter!

73, Tom.

John AE5X said...

Congrats, Tom, on taking the build-it approach! I wimped out and waited 7 months for a pre-built QMX but am happy with the result. I may even order a high-band QMX. Meanwhile, my QDX has been made redundant by the QMX so its sale will partially fund the high-bander.

Good luck on your build!

John AE5X

MadDogMcQ said...

Hi John, if this works out, I might order the high band too.

73, Tom.