Woo hoo! Finally taking my QRP Labs QMX on a POTA activation!

Those of you who purchased a fully-assembled and tested version of the QRP Labs QMX are, no doubt, patient people.

While you can order a kit version of the QMX and receive it fairly quickly (still, I believe), the assembled versions take more time as the QRP Labs crew is small and they build and test these by hand.

I ordered mine on June 5, 2023, and it shipped on December 27, 2023.

Truth is, I’ve had a QMX kit since Hans Summers announced it at Four Days In May (FDIM) prior to the 2023 Hamvention. I’ve been meaning to build it but, as many of you know, my life has been a tad crazy these past months and I never got around to it.

I purchased an assembled version of the QMX because I will be reviewing this one and wanted a factory-tested unit. I would have never guessed I’d receive the assembled unit before building it!

Familiar Form-Factor

The QMX looks so much like my QCX-Minis, I’ve gotten them mixed up in the shack! The menu system is very similar to the QCX, but there are some changes to accommodate band changes, modes, etc., as the QCX-Minin series is mono-band CW only.

The QMX, on the other hand, is a five-band, five-watt, multi-mode (CW, Digital, and likely SSB in the future) transceiver. It’s hard to believe you can purchase the QMX for as little as $90 (bare-bones) kit or $165 (fully-assembled and tested).

I initially thought I had an issue with my QMX because it kept shutting down the transmit function. Turns out, that was all user-error. I mentioned the issue on an episode of the Ham Radio Workbench podcast, and a couple of listeners wrote to tell me what I was doing wrong: I was feeding it too much voltage. The QMX doesn’t want more than 12V or so. If the radio detects even a temporary mismatch, it shuts down the TX to protect the finals, etc.

I was unintentionally triggering the QMX’s self-protection functionality!

Once I figured that out, I decided to simply pair my QMX with my Bioenno 3Ah 9V LiFePO4 battery. That would yield about 3 watts of output power and be a comfortable voltage for the QMX.

Vance Historic Birthplace (US-6856)

On Thursday, March 7, 2024, I finally took the QMX outdoors where it belongs! I had a one-hour window of time to complete a full activation. I decided to pair the QMX with my Chelegance MC-750 vertical.

My QMX is a “low-band” version that covers 80, 60, 40, 30, and 20 meters. I thought the top end of its band coverage would serve me best mid-day, so I planned my activation around 20 meters.

Setup was easy and simple. You can see the full set-up process in my activation video below.


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On The Air

I hopped on the air and started calling CQ POTA after sorting out my QMX settings–I needed to adjust the sidetone and I had to take it out of split mode!

I worked my first ten contacts in nine minutes. Obviously, the bands were healthy!

I continued working stations for an additional 16 minutes, logging a total of 25 hunters in 25 minutes. Not bad at all!


Here’s what this five-watt activation looked like when plotted out on a QSO Map:

Activation Video

Here’s my real-time, real-life video of the entire activation.  As with all of my videos, I don’t edit out any parts of the on-air activation time. In addition, I have monetization turned off on YouTube, although that doesn’t stop them from inserting ads before and after my videos.

Note that Patreon supporters can watch and even download this video 100% ad-free through Vimeo on my Patreon page:

Click here to view on YouTube.

QMX Initial Thoughts

As I say in the video, you’d be hard-pressed to have more fun with a $165 radio!

The QMX is a little rough around the edges, still–it is a work in progress and Hans is continuously improving the firmware having recently added AGC and, again, I believe SSB mode is on the horizon.

I noted in the video that there was a bit of audio thump in CW mode. At the time, I assumed this was due to the fact that my amplified speaker’s volume was maxed out and the QMX volume still fairly low. I assumed it might actually be a bit of the speaker’s fault. Turns out, though, it wasn’t.

Only a week or so later, my buddy John (AE5X) posted an article and video on his blog demonstrating the audio thump in his QMX. He also noted that Hans is working on correcting this. No doubt, he will.

QMX owners understand that this sub-$200 or sub-$100 radio pushes the limits on performance and price point. It’s an amazing bit of kit! Hans has done a brilliant job here and, no doubt, will continue improving it over time.

You’ll see the QMX in many future activations! I’m looking forward to hitting a summit with it soon!

Thank you

Thank you for joining me during this fun little activation! I really enjoyed putting the QMX on the air.

I hope you enjoyed the field report and my activation video as much as I enjoyed creating them!

Of course, I’d also like to send a special thanks to those of you who have been supporting the site and channel through Patreon, and the Coffee Fund. While not a requirement, as my content will always be free, I really appreciate the support.

As I mentioned before, the Patreon platform connected to Vimeo makes it possible for me to share videos that are not only 100% ad-free but also downloadable for offline viewing. The Vimeo account also serves as a third backup for my video files.

Thanks for spending part of your day with me! Have a brilliant weekend–get out there and play a little radio if you can!

Cheers & 72,
Thomas (K4SWL)

17 thoughts on “Woo hoo! Finally taking my QRP Labs QMX on a POTA activation!”

  1. Just received notification that my QMX has shipped. I ordered it 09 Oct 23. Looking forward to receiving it and trying a super lightweight POTA activation. I’m apprehensive about the “clicks and thumps” issue; I know Hans has prioritized a fix so let’s hope for the best.

    1. There seems to definitely be an audio “clicking” issue that is, oddly, band dependent and related to sidetone generation and the AGC system.

      There are lots of reports on the QRP-Labs forums on groups.io in which different users share their settings for mitigating the issue. From reading these reports and from experience with my own QMX in the field, I found the following to be most effective:

      1. Make sure you have the latest firmware on the radio.
      2. Turn the AGC system OFF.
      3. Set the sidetone to “Relative”

      Your experience may be different, but with these settings I am able confidently take the radio to the filed and comfortably make contacts.

      Keep an eye on the forums for tips on operating the radio and be on the lookout for firmware updates.


    2. Hi John, The current firmware implements a fix for the “clicks and thumps” issue and adds AGC. I finished my (20-10m) kit a few weeks ago and I find very enjoyable to operate. It has great receive audio.

  2. If you run FT* in Auto or Robot mode you can go take a nap and let the automation do all the work for you

    John VE3IPS

    1. He mentions in the video that he got it for his KX3 a while ago at four days in May. Its probably a homebrew solution someone was selling and not a commercially available product.
      The grippy material you can find at either target or Walmart if I remember correctly and the stand itself could be easily 3d printed or made using wood.

  3. Nice rig! hank you!
    I wonder how much better it is than the good old KD1JV’s MTR-3B? I like the sound of its direct conversion receiver.

  4. My QMX high bander kit arrived very quickly; less than a week from Turkey. I’ve been plugging along at it over the course of the last two weeks. Finished the main board yesterday and hope to finish the rest today. I’m excited to have an option for the high bands now that we’re approaching the sweet spot of Cycle 25 and summer.

    I’ve also built a linked vertical antenna for all of its bands as well. It was fun to build and it should be a good performer.

    Thanks the article and 72,
    Don, WB0ISG

  5. I’m excited to see this activation. I ordered my first QMX in May 2023, as soon as it was available, and got it mid-October. I was thrilled and then saw that someone had ordered a High Bands version and asked for that mod in the order comments. Now it’s definitely a regular thing. Today, of all days, I finally got the shipping info from Summers and expect to have it one the air shortly. It was about a five month wait but worth it. It seems that pre-build production is speeding up from the start of the QMX start date. That QMX part density is a bit intimidating as a kit, I’d probably screw it up.

  6. About the ham shack issues leading to your 9v operation decision : I sometimes miss that the “S” is on and the SWR protection has tripped. It would nice if the “S” flashed on and off when displayed as a reminder to those of us with old/full/slow brains that we screwed it up and need to adjust our setup. Especially helpful with those of us with multiple radios in rotation and memory potholes.

  7. Thanks for the tip Matt!

    Thomas… I’ve had my QMX LowBander (assembled) for six moths now. I think you should pair it with a TalentCell, it’s perfect.

    I velcro’d mine with the TalentCell and a Palm Pico. It’s paired with an old Android phone, free FT8CN software, and a short RA USB c/C cable for FT8. That and the Antenna of your choice, and it’s a wonder you couldn’t work some real Dx. The kit is compact, capable, and mot important fun! (Many thanks Hans!).

    Great report Thomas!

  8. Thanks for the tip Matt!

    Thomas… I’ve had my QMX LowBander (assembled) for six months now. I love this transceiver!

    I velcro’d mine with the TalentCell and a Palm Pico, it’s perfect! Paired with an old Android phone, free FT8CN software, and a short RA USB c/C cable for FT8. That, and the Antenna of your choice, and it’s a wonder you couldn’t work some real Dx. The kit is compact, capable, and more importantly fun! (Many thanks Hans!).

    Great report Thomas! Do some Digi!

    TU 72 de W7UDT

  9. Best bang for a buck, I love this radio, and it still developing, its better from version to version. I’m 99.99% CW op but also appreciate possibility to work on JS8call, and its so so tiny.

  10. Interesting voltage hickup. Looks like it might be ideal to get a lithium polymer battery for it. Smaller and less weight than a lifepo4, and a 3s will give you about 10.5-12.0v. Cheap too. Having “only” 500 or so full cycles instead of thousands is probably not an issue when it’s not used daily either.

    Just ensure it’s in a proper enclosure to protect it. I have one that’s just shrink wrapped, and it’s pretty vulnerable. I’ve thought of just replacing it with a 3 “AA” battery holder with some good, self protected 14450 li ion cells. Easy to take care of and could be charged individually, so no need for a BMS. Ideas?

  11. I look forward to the SSB implementation. I know it will be a while, and might not work as well as we’d like. But it will bring a lot of nice extra capability to the little radio!

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