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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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QMX Won't Transmit in SSB
7
I'm the proud owner of 2 QMX's. One I built myself (s/n136) and one that was built by QRP-Labs (s/n 1137). I installed the PTT mod in both units, and I installed 1_02_000 firmware on both QMX's. As soon as the SSB (beta) firmware came out, I built K6ARK's mini-mic and both the mic gain test and PTT diagnostic tested fine when plugged into the Paddle jack. I checked the mic wiring with an ohm meter and everything was correct. My problem is that I cannot get either QMX to transmit in USB or LSB mode by pressing the mic PTT button. When I press the button the audio blanks out but there is no RF output. However, if I switch to CW mode and press the mic button, it transmits a tone perfectly with RF output. I tried resetting the QMX's to factory settings and recalibrating them. I also verified that the SSB configuration is set to External Mic. Granted, I'm a newbie and I probably missed some setting or something else trivial, but I can't seem to figure it out. I have tried searching the QRP-Labs and QMX forums, but I haven't found a solution. Any advice would be greatly appreciated. 73 Chris - KE8VOD
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Weller WS51?
14
I noticed in a video I watched last night that Hans recommends a 60W soldering iron for building the QMX for quicker heat transfer. I have a Weller WS 51 that I have had for a long time. I am using Kester 63/37 usually at 325F. So is this set up good enough as I start a QMX+ build or should I get a higher wattage soldering ?? 73 Paul w2eck
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Microphone problems
7
QMX I have built two microphones. The Radtel one described in the Wiki and the Adam Kimmerly (printables one). PTT is tip to sleeve and the mic is ring to sleeve. In SSB, Input is set to Ext. mic When I push PTT on either microphone, nothing changes on the display. Checked for continuity, tip to sleeve has continuity when button is pressed. When I run the microphone test and talk into the microphone, there doesn't appear to be any modulation. Mic gain is set to the default 50. Obvious I am doing something wrong.
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QMX Manual Nomenclature Suggestion
2
Hello, While performing an inventory of my QMX kit (60m - 15m version), I had some trouble identifying the inductors I received. I believe the following two edits would make the manual's inventory section easier for the reader to understand. On Page 20, the FT37-43 inventory item should have "(dull black)" after it. On page 23, the T37-10 inventory item should have "(shiny black)" after it, instead of just "black". With some help, I was able to figure this out using info on page 38. Again, having these additional comments in the inventory section would be helpful. Cordially, Rob, AH6X
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#qmx Don¡¯t Use USB-C PD to power your QMX?!
84
#qmx
My QMX released the magic smoke yesterday and I quickly traced the smoke to a crater in D108, the 5.6V zener on the 5V PSU board. Having recently read Hans¡¯ excellent SMPS analysis (http://qrp-labs.com/qmx/smpsstep.html ) it got me wondering what could have caused the fault. I had been powering my QMX from a USB-C battery and this 12v cable (https://www.amazon.co.uk/gp/product/B09ZL1WZ4G). I then remembered that USB-C PD adapters typically start with the output at 5V and then shortly afterwards increase the voltage to that negotiated by the device (in this case 12V). This would generate exactly the voltage pattern Hans has told us to AVOID. I took a trace of the voltage power-up sequence, and this is the result (no QMX¡¯s were harmed in creating this trace). Output power starts at 5V for 120ms before increasing to 12V, perfectly creating Hans¡¯ disaster scenario and causing D108 to sacrifice itself to protect the rest of the QMX. Thankfully the rest of my QMX appears to have survived unharmed, thanks to D108. Conclusion: don¡¯t use a USB-C battery to power your QMX, unless you¡¯ve confirmed your adapter behaves differently! Cheers, Dave M0JTS
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QMX or QMX+ Which to go for?
9
Is there any performance difference between the QMX and QMX+? I'm about to hit the button and order a QMX+ but, since I will be using it pretty much exclusively for portable working (POTA, SOTA, etc) the smaller size of the QMX does appeal. Although having to pick a band set definitely does not. 10m and 40m are both bands that would be useful to me but 60m isn't since I currently only have a UK intermediate license (and 60m regulations are pretty inconsistent around the world) Anyone got any recommendations based on experience of building and using either? Thanks Mark 2E0OIW
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The radio is a Ver. 1 QMX plus that in general performs exactly like I expect. It does not have the GPS option installed, and there is no battery in the clock battery slot. The radio is used for CW only. As the title suggests, I have an approximate 1000 tone on only 12M and 6M bands. It is internal, in that I can remove antenna and it's still there. It does not change in level or tone while tuning around the band. It appears to de-sense the receiver a bit, as a signal must be pretty strong for me to be able to copy it on 12M. There is normally a 'beat' frequency between the received signal and the tone when I can copy someone. I have run the I/Q sweeps in Putty, using a raspberry pi computer. The tone is present with or without the computer attached. The I/Q sweeps look very nice on the lower bands, and begin to deteriorate as the frequency goes up. They are still showing the two sine waves, but are a bit distorted( not a perfect line of x's ). This deterioration is also noted on 10M and 15M ( to some extent ) and the sweeps for 12M and 6M are not suspiciously worse than others. 10M works flawlessly, as do the other bands. The remaining filter sweeps look good, with some tweaking needed possibly, but totally functional as is. I have a set of QMX HB and LB radios to compare symptoms, and the HB QMX does not have the 'tone' on 12M when swapped into the system. I am curious what path to take troubleshooting this issue. I did not find anything in the archives that addressed this strange behavior. Thanks & 73 Dick W4PID
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Errata for Rev 3 QMX+ Assembly Manual
3
Not intended as a prompt for actual updates to the excellent manual, more for information purposes in case someone is compiling a list for when Hans accidentally falls into a cloning machine and can spend time updating manuals instead of the important stuff like bug fixing and adding new features. Also, apologies if this has already been posted but the search facility doesn't work well for me unless I guess exactly the right search terms. The warning at the bottom of page 54 about power supplies is duplicated at the bottom of page 55 and then again on page 56. Given the critical nature of this warning, and that 99% of us would assume that the device would work safely on a standard bench supply or battery, repeating the warning may not actually be a bad thing so maybe it would be better not to fix it! On second thoughts, given the humorous writing style of the instructions, this may be actually be a deliberate ploy on the part of Hans to make sure we get how critical this is. In which case, well played sir - you got me!
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File /QMX-PC-Controller6A.html uploaded
6
#file-notice
The following items have been added to the Files area of the [email protected] group. /QMX-PC-Controller6A.html By: Paul Harrison <dj0cu@...> Description: QMX PC Cat Controller with 100KHZ Bandscanner including Morse Decoder. Experimental. No installation necessary. Save to HDD and run in a browser.
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QMX Standalone PSK31
4
One more possible PSK31 feature: Allow text input using a CW paddle instead of a keyboard. Note that the QMX UART might be tied to some Bluetooth thingie, allowing use of a cellphone. I'm creating an approprate new thread, conversation started by hijacking this other thread /g/QRPLabs/topic/113046586#msg145208 Conversation thus far is summarized below: On Tue, May 13, 2025 at 08:10 AM, Jerry Gaffke wrote: Making PSK31 easy to use on the QMX with just a keyboard jacked into one of the UART ports would make it a killer PSK31 machine for portable use, displaying received text on the LCD. Send that text out on the UART TX line to be displayed on an optional larger LCD and/or possible logging. Optionally append a 32bit CRC at the end of each transmission so correct reception can be verified, this might be a critical feature for serious use in emergency communications. With thousands out there, the QMX could single handedly revive PSK31 activity on the bands. There are better digital modes these days, but PSK31 is good enough, simple, and easy to implement. On Tue, May 13, 2025 at 09:12 AM, Daniel Walter wrote: Jerry, I really like the idea of reinvigorating PSK31 by making the QMX do stand-alone PSK31. It is a great mode for kybd to kybd QSOs. I know you can do that with JS8, but at a very significant time cost compared to PSK31. I would welcome that development. There's also this old post about my attempt 20 yrs ago at implementing PSK31: /g/QRPLabs/message/139336 Ideas from the file /g/ATSprint/files/Archive/KE7ER/pskuc.c may be useful for Varicode encoding/decoding, but the method of converting received audio into a stream of bits is best ignored if your processor has multiply in hardware. Jerry, KE7ER
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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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Internal battery for QMX+
10
Has anyone installed a rechargeable battery in the QMX+? If so, would you share the details, such as what brand of battery and how you wired it inside the QMX+ case? Thanks. Hiroki AH6CY
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QMX receiver went deaf
10
Last night while playing with my qmx the receiver went deaf. This happened after txing on ssb with IQ mode on and panadapter open. I was using a mic connected to the radio. The S meter with antenna dropped to nearly nothing and I can only hear white noise now. The radio will still put out 5w. I ran my little signal generator into qmx and on receive I hear nothing at -33dbm. At 0dbm (I know quite strong) the signal will get through. Any thoughts? Thank you Ryan KK6DZB
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QMX SSB QSOs
5
Hi Guys, the SSB modus for the QMX is awesome. Even with a small Magnetic Loop antenna. I?m Using a microphone of the QRP-GUYs from California, USA. At the Antenna connection (bnc) I also use a LED SWR bridge from the QRP Guys. So I can tune my magnetic Loop antenna with full power about 4 Watts with 11V Supply(3 Watts keep in the bridge resistors..lol, 1 Watt will be used for the measurement) . When the LED goes out, I can switch into the operation mode. I NEVER switch of the SWR Protection off (SWR3 in the Menue of the qmx). Has anybody an idea, if the internal microphone can be activated in the nearer future or will there maybe have to do any hardware change ? enclosed my video :) : https://www.youtube.com/watch?v=NKZ_0NkJAIA By the way, I?m using a DC-DC converter to reduce the voltage to 11-11.5V . And yes, it doesn?t make any noise, believe me, Its a quality module from an european electronic supplier and not a cheap piece of sh.. from Temu ! Im using toroids around the voltage supply cables (lpf). Have much fun with the QMX. YOu really did a great job Hans , 72 de Matt, DL1SER
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#QMX Glitchy encoders? Not any more ?
24
#qmx
My V1 80-20m QMX has had issues with a glitchy VFO encoder. It would often skip in the opposite direction to which it was being turned which made tuning a bit awkward and menu selection even more so. After taking the encoder out, dismantling it and cleaning the contacts, the issue was much better but still not great. I tried replacing the encoder with an AliExpress part that was linked in another thread but the A/B switch contacts were reversed on that one, requiring short jumpers to be run from the two outside encoder pins to the pads on the opposite side. Even then, those encoders were a bit pants (I tried a couple). On a hunch, I re-fitted the original encoder and soldered a 10nF SM capacitor from each of the two outer pins to the common ground pin. This has now completely cured the glitches and the encoder works smoothly and accurately. I can now tune accurately and step through menus in the order they're meant to appear. Happy Days ?? I've attached a photo of the bodge in case anyone else is having similar issues and wants to give it a try. If the photo doesn't appear, here's a link: https://photos.app.goo.gl/RT9evC3BRUaaDSKe6 Cheers, Ronan MM0IVR
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Encoder fix that worked for me
5
#qmx
#rotaryencoder
I know that many of us have encountered issues with the QMX tuning encoder giving strange results, like large jumps or only counting in one direction. After cleaning up a solder bridge between one of the pins on the two pin side and the encoder body the problem went away for me for a day, then returned. What did work for me seemingly permanently was to exercise the encoder several full revolutions in either direction while holding the stem button down. I don't know what the internals look like on these but that has 100% cleared the wonky behavior. It has been 2 weeks at this point with no more erroneous encoder behavior. Hopefully this will also save some folks from needing to replace the encoder or fully dismantle one for cleaning / troubleshooting. 73, Greg, N1TR
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A completely different approach to the HTML console published on this forum but as I use Flrig to control my rigs and flrig does not support Hans' excellent recent additions to the CAT codes, I am developing a widget which supplements flrig. Currently, this allows for the selection of new modes, indicates the LCD contents on your PC, and has meters for signal, SWR, and power. This can be seen in operation here: https://www.youtube.com/watch?v=lr-OomSTS7U Anyone wishing to try this out, then it can be found here: https://github.com/sipsmi/qmxwidget It's just proof of concept at the moment, and I will get around to tidying it up, but it works and I find it useful. 73 Simon G0FOZ
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QMX+ damaged internal microphone?
#QMXp
#QMXplus
Hey there! I am coming to the end of constructing my QMX+ and assembling the display board. I've got to the point of soldering the internal microphone and when I have got it out of the bag of remaining parts, I have found that the positive lead out of the body of the microphone is loose. I guess this is the best description of it. The lead can go into the microphone body a little bit, but doesn't come right out of the body and it doesn't seem to be attached to anything internally. Have I got a damaged microphone? If so, can someone advise me if I can source a replacement? 73s Glenn VK2AXV
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PSK31 with QMX + Digipan
10
Hi all, just some hints how to configure QMX and Digipan. QMX: - SSB Menue: Mic AGC ON; Input: USB; MIC Gain 50; Compression 0 USB Gain: Adjust for 50% power on idle PSK Signal. (I am using USB Gain 5) - VOX: ON - CESSB: ON Make sure your antenna SWR is ok. If "Protection" is on it might stop your TX. (Its not the fault of Digipan, hi) DIGIPAN: Set your Serial port (where QMX is connected), no RTS/DTR as we are using VOX. Soundcard: Type: "Computer soundcard"; Input/ Output: "digital interface QMX"; sample rate: 11025 Thats it. Ready to make first PSK contacts! Good DX and hope to work you in PSK. 73 Mat DF2OF
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