Sticky
#qmx #Firmware release 1_02_000
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#qmx
#firmware
Hi all SSB firmware was released into beta on 17-Mar-2025 after 9+ months of development. Many thanks to everyone who bravely helped test it and patiently provided their feedback and observations. There are now quite a few YouTube videos, forum reports and other social media mentions about on-air successes with QMX SSB. Now that it has been at least 6 weeks in beta and I believe most of the issues have been resolved, it's time to promote it to an official version. I have called this version 1_02_000 and published it on the QMX page http://qrp-labs.com/qmx where I have also published the updated operating manual, which grew from 111 pages to 134 pages. The main changes are: SSB (obviously!) including CESSB, TX Equalization, Mic AGC, VOX, Pre-distortion and and and... Addition of up to two more USB Virtual COM serial ports (up to three total). All of the hardware tests such as RF and SWR sweep, and Diagnostics, are now available on the LCD too. New CAT commands for LCD contents, S-meter, AGC-meter, Power meter, SWR meter, SSB source Complete list (relative to 1_00_027 the previous official version): SSB modes added (USB and LCB), with CESSB, TX Equalization, Mic AGC, VOX, Phase pre-distortion and more Rationalization of menus, grouped into CW, Digi and SSB submenus (now Keyer and Decoder are submenus of CW) Added up to two more USB Virtual COM serial ports (configurable) LCD versions of AF, RF, Image, LPF, Test ADC I/Q sweeps (miniature graph on LCD) New function PA mod. test to check operation of amplitude modulator Diagnostics screens are now available on the LCD interface too Now remembers previous menu location on ALL menus regardless of nesting level Add way of forcing factory reset, press Menu (left) button during power-up Change TX color in diagnostics screen from red to blue, to avoid confusion since red things are errors Added CAT LC command to retrieve LCD contents Added CAT commands SA (AGC meter), SM (S meter), PC (Power meter), SW (SWR meter) Added CAT command SS (get/set SSB input source) Bug fix: PTT P did not work properly Bug fix: Incorrect PA voltage display on the Diagnostics screen 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl
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FDIM 2025 - Bringing SSB to the QMX (Hans's presentation)
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Enjoy https://www.youtube.com/watch?v=bsDBcFXgHbY 73 DE muhsin TA1MHS
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QMX+ Broken Toroid Core
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I'm in the midst of assembling my 2nd QMX+ and I just busted one of the Shiny Black T37-10 Toroid Cores... DAGNABBIT!!!! So, where's the best place to by only one or two Toroid cores in the US? 73, -Ed, WG5F- Tulsa, OK
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QDX Low Receive but Xmit fine
GM QDX¡¯ers. I was gifted a QDX still in kit form so I spent a day building it this week. Except for one band, 80M, I got between 4.8 and 5.4W output which is optimal. The cure for that was to just put some more heat and re-solder leads on the inductors. I get reports of anywhere from -2 to -20. My issue seems to be with the received signal getting into WSJT-x. Although I¡¯ve made a dozen or so contacts on 20M and 30M, the db meter (I¡¯ll call the S meter) barely hits 15db maybe 20db on a real strong signal. Never higher. Most signals reports I give out are in the -17 to -10 range which would correlate with the db meter. I know from experience it should be a lot higher than that. I¡¯ve seen no signals decoded on 40M or 80M but I haven¡¯t listened at night which is going to be the most likely time to see those out in the NW. I¡¯m using a retired MacAir as the computer using OSX. All radio and audio settings are set to the QDX settings and to full audio by default. The Radio is set to a Kenwood TS-440. It gives the impression there is not enough signal/audio getting into WSJT-x but I¡¯ve got no way to adjust that. The antenna is a hexbeam for 20M and a 100ft high loop for 30/40/60/80 The version of QDX is 1.4 Any insight into this receiver issue would be greatly appreciated. I can live with the way it is now but I think with the receive signal stronger, it will show me a lot more stations. It may be MAC thing. I just don¡¯t know. Thanks. John / K7RLD
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Solder pot for toroid leads
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Does anyone use Solder pots for tinning and removing the enamel from the toroid leads? Any hints and tips? I see a cheap one on Amazon for about $20. Any suggestions if I should buy special solder for this, or use my normal Kester 63/37 solder in it?
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QMX SWR measurement is not correct while using with PA
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Hello! I've noticed that SWR protection stops TX when I try to use QMX with one of my PA. When I measure SWR with connected PA threw QMX hardware test it shows 1.8-1.9. And it causes SWR protection actuation (even if SWR protection level is 3 or 4 by the way...). When I do SWR measurement with Nano VNA or another transceiver they measure SWR = 1.1. So it looks like QMX is incorrect. That is strange... When I do not use PA then QMX SWR measurement tool provides correct figures (compared with Nano VNA). Any ideas? BR/Sergey UB3AZK
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QMX+ SSB audio distorted on one band only
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Hi, I installed the 1_01_003 beta firmware yesterday and I am amazed at how it has transformed my QMX+ (rev 2 board). I am, however, perplexed at the fact that the SSB audio is distorted (on another receiver) only on 20M. This only occurred after calibration and the audio becomes absolutely clear again after disabling the phase predistortion. All other bands have good audio with and without predistortion, and the RF output is within normal limits on all bands, although 20M is a little lower than others at about 3W. I am using a 12V stabilised PSU and a good dummy load, via a Bird isolator, giving me a solid signal into my receiver. Trying to think of an explanation made me consider that the LPF used for 20M (LPF 3) may not present a good load to the PA, so I looked at the LPF sweep using PuTTY. Here is the sweep for 20M: The 14MHz line is in a less than ideal part of the curve, whereas the bands which share this LPF are better placed. Is this significant? The phase calibration sweep for 20M also looks odd and is different to the others which are all nice curves (except 160M which sounds fine!): This is the 20M USB IMD sync optimisation curve, the title of which has been overwritten by the asterisks of the curve. The 20M USB curve looks identical: Here is the adjacent band 30M curve for comparison: Everything on the board looks good and the radio otherwise works perfectly. I am perplexed at why only one band is distorted (it really is unreadable) yet 160m, which has similar calibration curves but a great looking LPF, Sounds OK. Any ideas? The simple answer is to switch off predistortion, but that doesn't solve the problem! 73 Ellis GM4GZW
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Hi SWR, sometimes
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This seems to be a complex problem because I do not understand what is happening. I will try to explain as best as I can. QMX mid bands built for 12 volts and Z-11 Pro auto tuner. I start on 40 meters and go to hardware then SWR tune and start the tune. The tuner light move and ends when a <1.5 SWR is reached. I then go to iambic and send CW at about 20 wpm. After about 10 dits the tuner jumps up to over 4 and the S protection letter shows on the screen after the last number. I cycle the menu, go to hardware, SWR tune and it shows <1.5 SWR. I go back to normal CW and the same pattern shows up again. It happens on multiple bands and is frustrating because I can't complete a POTA contact let alone a ragchew. My sBITx is also low power 1 - 4 watts and does not do this action with the tuner. Any ideas where to look? 73, Dean/ N2TNN
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QMX won't start after firmware update to 1_02_000
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Just upgraded from pre-SSB version to 1_02_000 and now the QMX doesn't start again. - Only POP at headphones - No display - No serial port visible at computer - With new upgrade all HW tests worked fine Battery voltage OK (not of course measurable from device). The device worked fine before this upgrade. What should I try to fix this?
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QMX CW bandwidth
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Hi, my QCX has been modified for a passband of around 900Hz and has found more use after the modification. I have a half-built QMX+ and the specs say that cw filter is adjustable from 50-500Hz. Many seasoned cw operators prefer much wider bandwidths for general cw working. I usually listen with around 1,2kHz BW, in tougher conditions the narrower BWs are a blessing. As my QMX+ still awaits to get on the air I want to ask if it?s possible to make the bandwith wider tha 500Hz in CW mode? If that is not the case, I would like to add this to the list of changes in the software of the QMX. 72 Ari OH9VL G-QRP 2068
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Introducing QMX CARROT
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When Elecraft introduced the KH1 a year ago, I was immediately enthusiastic about the concept. A small and lightweight shortwave radio with an integrated telescopic antenna. This means that, weighing less than 400g, it can be used in any suitable location on shortwave. So I wanted to build something myself. I immediately began my own experiments with telescopic antennas for 7-30 MHz. This confirmed that a counterweight is absolutely necessary. This wire, which is a quarter of the wavelength long, contributes significantly to the radiated energy. So the idea arose to forgo the telescopic antenna and experiment with end-fed wires twice the length. Of course, it makes sense to stretch the wire as high as possible. But I also got respectable reports with EFHW lying on the ground or in bushes. In this place the antenna may detunes itself, so a tuner is necessary, as well as the standard 1:64 transformer (Unun). The tried-and-tested resonance circuit (Fuchs Kreis) performs both tasks. Once the antenna issue was resolved, QRP Labs brought out the QMX. The ideal TRX for my projects, and now even capable of SSB. Now all that was missing was a suitable housing with an integrated battery and a speaker with an amplifier. Then a paddle for CW as a contactless touch key directly on the device. And the QMX Carrot was finished. But it wasn¡¯t that simple, because everything had to be as small and light as possible. It now weighs 340g and measures 15x8.5x3.0 cm. I¡¯m happy with that. 73 Chris https://youtu.be/0kksiWVOtnQ
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QMX+ RF output fluctuates wildly
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#QMXplus
#troubleshooting
Assembled my QMX+ and it's working. I had a couple of issues related to enameled wire not making good connections that were resolved. I know it's working, I've made contacts on several bands successfully, including some decent DX, all on FT8. What bothers me is that the output power seems to jump around wildly. If I go to the diagnostics screen and key the transmitter, the Bias SMPS shows fluctuations in current that correspond to the fluctuations in the output power. The Duty cycle on the Bias SMPS always shows 0%, even as the current jumps around in the red. I suspect I've managed to damage one (or more) of the surface mount semiconductors. At least that's what my reading on the subject would seem to suggest. What I need is a test that can be done with a multi-meter that would shed some light on the problem. I can probably resurrect an oscilloscope if I need it, but I'm hoping someone can lead me to a simple voltage or resistance test that could help isolate the problem. My last problem was related to soldering and enameled wire which was easily resolved. I'm hoping this issue can be resolved without major surgery as well. Thanks in advance for all of the good advice I'm about to receive. Andy WB9YXA
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RIT in N1MM
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I still use TS 480 for the setup of N1MM. When I am in Run and press the up or down key the QMX + changes to RIT .- .030 but cannot be modified then. I have to exit from that on the QMX+. It would have been perfect, if the QMx+ would follow the RIT in run. any suggestions ? -- Martin DK3UW
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QMX+ firmware feature request
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I'll start by saying I think if this as a "nice to have" change: I use a manual antenna tuner and the built in SWR bridge is great for checking the state-of-tune. In a (my) "perfect world", the "Tune SWR" would present a full width, bottom line, bar graph of the VSWR, rather than a single number. It's hard (for me) to spin the tuning knobs looking a flickering numbers. Just a thought. Thank you Hans for producing such a great radio! -- 73, Brent DeWitt, AB1LF Milford, MA
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R520 Wrong component value.
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When testing my newly built QMX+ I was getting high SWR readings while running the diagnostics SWR test. Even when connected to a dummy load the readings were around 2.7 to 1 across all bands. I removed and re-wound T507 (twice) but could not resolve the problem. So I removed T507 for a third time and started to check component values around the bridge circuit. I found that R520, although marked as 68X (49.9 R) , actually measured as 124.5 K. Has anyone else seen this problem. Regards Stephen
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My 20M band QCX+
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After a few days of work I completed my new QRP-Labs Xcvr after having built several years ago a Hi Band QDX. It was a real pleasure, no surprise due to an excellent manual and the adjustement and alignment were done today without dificulty. Next step will be to connect it to my Alexloop antenna. To be sure the 6 aft connectors whould slide nicely into the holes of the back plate I had screwed this plate to the lower enclosure and slid the main PCB each time I added a connector to check its position before finishing to solder it. The first difficulties I faced were to fit the LCD module and the front panel PCB to the Front panel of the enclosure : I had to cut slightly the nylon nut close to the potentiometer and I could not put in place the other nylon nut close to the encoder, I just left it near the hole in order to keep the good distance between the LCD board and the front PCB. The Last difficulties happened when I wanted to slid the main PCB inside the enclosure after having put in place the four 12MM spacers which hold the dev kit, the nylon screws below did not slide easily and I had to push quite strongly the PCB inside the enclosure. WELL I'M HAPPY WITH THIS WONDERFUL KIT AND I'M GRATEFUL TO HANS FOR THIS NICE DESIGN.
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50 Watt Power Amplifier - Low Power, High Harmonics
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#50w
#50wpa
Hello. I'm assembling a 50 watt power amplifier for use with a QCX+ that I assembled last month, for the 80 metre band. I have very high harmonics at the output of T3 - as a result, I get only about 9.3 watts out when running at 13.8 V. Output from the LPF looks OK on the 'scope. I found the excellent videos by NA5Y which shows the output of T3 should be much closer to a sinusoid than what I get. I also found the discussion with KO1KR in August of 2020, but unfortunately I can't see his scope photos so I don't know if he had the same problem. I've since skimmed through the many discussions on this forum but haven't found the same issue exactly, though I did check out some of the suggestions given here. I found the amplifier took 67 mA with R5 fully CCW - I adjusted R5 till the amplifier drew about 70 mA with the QCX+ key-down in practice mode. Here are my scope traces: 0092 is the gate drive, yellow is Q1 gate, purple is Q2 gate - all is well here. 0090 is the drain voltage, Q1 in yellow and Q2 in purple - these look like there is oscillation ? 0091 is the voltage at the output of T3. This has a lot of third harmonic and doesn't look like the waveform NA5Y showed at this point. (QCX+ was set for 3.520 MHZ , amplifier connected to a dummy load.) I thought that perhaps my bench power supply is doing something odd when the amp is drawing power, but I probed the 12 volt line right at the barrel connector and the 'scope showed almost no disturbance of the +12 v supply. In frustration, I observed the output of T3 with the 'scope set for a long capture - it almost looks as if the distortion grows with time, for the first few tens of microsceconds the scope showed a small but sine-ish waveform, which over the span of a few hundred microseconds got wigglier and wigglier till it developed into the mess seen in my scope capture 0091. I've checked DC continuity to the windings of all the transformers and coils. I did find a bad joint on the primary of T1 but I cleaned it up and can now get power out of the amplifier. I haven't yet checked bias on all the 1N4007 diodes but the input looks quite sinusoidal at R3 closest to the input. The few watts the amplifier does produce look OK at its output. The QCX+ makes about 4.3 wats into a dummy load (43 V peak to peak) at 13.8 V DC. I'm assembling these units for a friend, and I had really hoped to have them ready for Field Day this year. The instructions are excellent and I have followed them closely. What can I look at next? Bill VE4STW
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Release of version 2.0 of ABS solution for QMX+ (Automatic internal antenna tuner, internal battery and internal speaker with audio amp)
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#PSU
#QMXplus
#audio
#ABS
#ATU
Hi, I have released a version 2 of ABS solution. Please refer to the readme front page file at the git repository for full details and release notes: https://github.com/AC8L/QMX_Plus_Autotuner_Internal_Battery_Speaker/ The release includes new PCB fabrication files, BOM and detailed build instructions. This release took into consideration lessons learned and a feedback from first group buy participants fearlessly organized by Cal (AD8Q) and Stan (KC7XE). -- 73, Sardar (AC8L, 4K6SA, VA3DUA).
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SSB Cal problems with QMX (not +)
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I have been running firmware 1_02_000 on my QMX+ with good results on CW and SSB (haven't tried Digi yet) since the release of that firmware. So yesterday, I updated my original QMX with 1_02. The update went fine, and operation on CW was great, but I can't get all the SSB calibration procedures to look right. This is an 80, 60, 40, 30, 20 QMX, built for 12v (same voltage as my QMX+). The cals failed to complete on 80, 60, and 30. On 80 and 30, I get an error message saying "Change over 30 degrees" from the phase error cal and it stops at about dac=~1100 to 1300. I got a similar error on 60m, but this cal ran successfully on 3 subsequent runs. On the USB IMD sync, the final table in the upper right says 80m:15, 60m:74, 40m:23, 30m:62, 20m:26. In addition, 80m and 40m responses were almost flat - 80m ~140, 40m~100. On the LSB IMD sync, the final table in the upper right says 80m:74, 60m:74, 40m:29, 30m:15, 20m:26. In addition, 40m and 30m were almost flat - 40m ~280, 20m ~ 250. Also, for whatever reason, the y-axis max on 80m was ~7000000, and the y-axis max on 60m was ~1000000, both 1000 times higher than all other bands. On the ADC I/Q tests, the curves looked about the right shape (compared to samples in the oper. manual), but the upper left and lower left numbers were not very symmetrical. 80m 42183/-42067 60m 52338/-52457 40m 55808/-56412 30m 53881/-54284 20m 36459/-35947 Mic test works fine. PA Mod test looks good. Diagnostics look good on all bands with the following RF outputs. 80m 4.0w 60m 4.3w 40m 4.4w 30m 3.7w 20m 5.4w All tests with dummy load with Diagnostics showing SWR around 1.1:1 Any comments or suggestions are welcome. 73, Randy, KS4L
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Calibrate the QMX's time through Android APP(FT8TW)
I wanted to try using WSPR, but every time I reboot, I have to set the time on the QMX again. A friend told me there's a GPS module that can help calibrate the QMX's time. I thought to myself¡ªmy phone already has GPS, so why buy an extra GPS module just to set the time on the QMX? So, I added a feature to calibrate the QMX's time through FT8TW. https://youtu.be/l8dey0vc6_E
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