Hallo Ludwig
I had a completely opposite idea… 
73 Armin
5 Likes
Hello Armin,
why not. For each band one LPF and the ratio from the highest and lowest frequency is lower than the ratio for the low band version.
73 Ludwig
2 Likes
A new version of the firmware 017 is available. Hans did a great job 
S-Meter and AGC have been implanted ( for CW operation). There are a lot of parameters with AGC but it works !!
I had a small bug after the update… RX was very low … I think that the audio gain in the Band Configuration menu (terminal mode) was not very well initialized. Reading their values in this menu resolved everything.
More tests in the field Wednesday during SOTA activation !!!
73 Nico
6 Likes
Wow! I ordered a QMX kit last week. It arrived already! That was a lot faster than I expected! Kudos!
(To the US. Using FedEx shipping option.)
2 Likes
I tried adding a built-in speaker to QMX.
The speaker is too small, so the sound isn’t very good.
Youtube
6 Likes
Today, I did the “maiden activation” with my new QMX on DM/BW-235.
After getting a few hints on what I might have done wrong during assembly from several OMs at the SOTA dinner in Friedrichshafen as well as from Hans at his booth, I finally managed to troubleshoot it, which took much less time than expected. Thanks again to everybody who helped and gave me moral support.
I ventured out with my trapped EFHW with which I could test the bands from 20-60m. Quite happy with the performance, I had the QSOs needed for successfully activating in no time. Then I QSYed to all bands for which I had the antenna for and found no issues with all bands. In the end I was struggeling a bit with 60m, not because I had no reception or so, but my USB to 12V converter started acting up since it got hot after a while.
Besides that, I experienced only a intermittent issue with a decoder which would QSY down but not up, which it didn’t do when I checked it at home before and after the activation. I just re-soldered all joints of the encoder and all related connectors and hope the problem will not re-appear during the next activation.
I didn’t to a direct comparison of RX performance with my FT-817 yet, which I had with me as a spare. Let’s see how many activations it takes to get enough confidence in the QMX so I can let the 817 at home.
73 Jens HB9EKO
4 Likes
Not quite the same thing but I have confidence in my QCXmini radios to take only them on an activation. A 20m model and a 30m model both do around 4.25-4.5W. The 30m is viable on 40m with 30m coils and runs about 2.75W. I’ve done 2 vacations when they were the only radios I had and have qualified every summit I tried, 2x CT and 5x GW. Plus a few test activations in GM.
QCX ODX is YC2VOC on 20m using an EFHW.
5 Likes
I took my QMX up Monte Grappa (I/VE-197) yesterday. It would only be the 3rd activation for this 60-15m version. The radio has been working fine, the problem was, after ages spent carefully setting up, I had forgotten the power lead. I had to go back down to Bassano del Grappa and buy a power supply with swappable dc plugs. I will try again later this week. Plenty of time for SOTA as the weather is not too good for paragliding at the moment.
73 de OE6FEG
Matt
3 Likes
I am just about to start the build of a 60-15m version.
9v or 12v?
What are users powering the radio with please?
My usual battery’s are heavier than the QMX and have a charged terminal voltage a bit higher than the max 12v needed.
Thanks
Tim
G4YTD
2 Likes
I also have a 20 QCX mini and love it. It’s not that I don’t trust the radio but rather my own soldering skills. 2-3 activations without such intermittent issues like I had yesterday and I’m sure I did not build any traps Next time I’ll also take my PD power bank with me and use the cable that nails it to 12V, that seems more reliable to me than the USB to 12V converter which started acting up after getting hot.
I also feel tempted to order a mid band version, since 60m-15m is what I use for most of my activations, but first I need to finish the QMX+ which I started building. These QRP Labs kits tend to be pretty addictive once you get the first one working
73 Jens HB9EKO
5 Likes
I have a 60-15m QMX I built for 9V ops. It works well from 8 NiMH cells, but I really like my 20000mAh PD powerbank and 9V trigger cable. It runs for days…
va3rr
2 Likes
I built the original kit as 12v. It still works on 9v or less, just a bit less power out.
This gives me more options to power it…
So far I’ve used a pack of “Eneloop” rechargeable AA cells giving about 10.5v.
2 Likes
Thanks Russell, there is a stack of Enerloop cells floating about here somewhere, a good reason to use them.
2 Likes
Thanks Adrian, the wider option of input voltage makes sense.
We are expecting rain later this week, so a good opportunity to get on with the build.
2 Likes
Building for 12V does offer more flexibility - IMHO, it is prudent to run data modes at reduced power.
And PD trigger cables are also available for 12v…
va3rr
2 Likes
I took the step and joined the dark side!
I wasn’t mega excited about the QMX when first announced and then I’ve mostly heard tales of woe about the rig.
I’ve patiently waited for over a year and I felt that the QMX is now mature enough to give it a try. I received the shipping notice on 31st December 2024 after using Christmas money from my XYL’s mother to place my order with QRP Labs. The kit arrived on Tuesday 7th January in good condition and very well packed. I opted to use the DHL shipping option.
I manged to do three sessions of construction spread over three days, each of around 2 hours.
I thought I’d messed up loading the firmware as I accidentally dragged both the unzipped firmware file and the zipped firmware folder across to the QMX. Supposedly the expected behaviour is that the QMX self resets after successful firmware delivery. My QMX just hung. I thought I’d bricked it. 
Reluctantly I removed the power supply lead and then plugged the QMX back in and pressed the power on button - amazingly the QMX sprang to life and proudly showed firmware 027 on the LCD.
Using a wooden stick as a pokey tool as I was able to adjust the low pass filter inductors, as needed, to get at least 4 watts out on every band using 12v as the supply voltage.
Initially I thought the QMX had a fault as no power output was showing on computer diagnostics page and also there was very little audio making it in to the computer. However I think it must have been user error or maybe RF pick up on the USB cable as I gave it another try on a different day and then everything worked as it should.
I think investing in a really good USB cable would be a good idea.
I gave the QMX a test run on 15m this morning from White Hill G/SP-006 and it seemed to work ok although I wasn’t keen on the audio from the rig on CW mode. I think I should be able to get the audio more to my liking by playing with the filter and agc settings.
Wellies are essential wear for White Hill in winter!
So, that’s it, I’m now a member of the QMX club!
73, Colin
19 Likes
Good signals into Pickering Colin, 115 Km. Sounded like ground wave on 21061 KHz but can never be sure on HF. It looks like its another successful home construction project, well done.
73 Phil
4 Likes
You sounded like DX, as you do on the higher bands. Quite a bit of echo. I’m not knowledgeable about propagation but I’d suggest some phase distortion due to multiple paths.
I felt HF was different to how I expected it to be today, I set my dipole broadside to Whernside, which I could see, and yet the signal from Richard @G4TGJ on G/NP-004 was weak and noisy with me. We exchanged mutual 559 reports. It was LOS! I expected earbending 599+. Weird.
Whernside (left) Ingleborough G/NP-005 (right) from White Hill G/SP-006
73, Colin
4 Likes
Tim, I built mine for 12 V.
At first I was using my 12.8 V LiFePo with 2 or 3 diods in series to drop voltage. Later I bought an 11.1 V (3S) LiIon with less weight but 2.6 Ah, good for at least 6 or 7 h of operation. The output at 11 V is only a little bit reduced.
73 Ludwig
But be aware when TXing the current is around 1 A or a bit higher.
73 Ludwig
1 Like