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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High current draw on initial power up
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#qmx
#troubleshooting
I received my kit for a high-band QMX this Tuesday, and have been working off and on over the course of the week to assemble it. I've gotten to the point where it's fully assembled, and after several close inspections under magnifying glass and microscope, I can't find any significant defects that would lead to the problems I've been seeing, outlined below I'm powering the QMX from a 10V, 250mA current limiting DC power supply. The core issue is that the board (That I have never programmed) is drawing far more current than the assembly document suggests it should at this stage) The different cases I've run: Main board connected to power, no additional boards attached: 0mA drawn Main board connected to power, PS #2 board attached, all others detached: 0mA drawn Main board connected to power, PS #1 board attached, all others detached: Initially current limited to ~8-9V @ 250mA. After an inrush period, stabilizes to 10V @ ~100mA Fully assembled QMX: Current limited to ~6V @ 250mA. LCD screen turns on with solid black squares displayed. Appears as a usb device immediately upon plugging in to a computer, without pressing the potentiometer button. I've been focusing my troubleshooting efforts on the interaction points between the main board and PS #1, and haven't found any obvious shorts. Checking the pin header connection to PS #1 with the board attached, I didn't see any shorts to ground. I also double checked and ensured that there weren't shorts around the power amp transistors, and around X201 where I saw VCC being used. I've attached photos of the back side of the main board, and front side of PS #1 as installed under a magnifying glass below. If any other pictures are required let me know and I can provide. Note that there is some debris near the PA transistors in the second photo. I cleaned that and tried again, and the board still enters the current limited condition. Thanks and 73 de VA3KBY
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New QMX+ Calibration victim
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Hi, I¡¯ve had my QMX+ for a number of months and had tested the then beta now regular SSB firmware with good results except pretty low output power in SSB. As I had never gotten around to fine tune the LPFs when building it I decided this was the logical next thing. So I fiddled with spreading and compressing turns on the toroids and managed to get all bands to between 4 and 5w output for CW except 160m that was already at 6w. Running 12.0v input and build for 12v Being happy with results I then first tested resetting to factory defaults, and then tested SSB output power. Still max 2-2.5w according to the Bird. I then decided to run the SSB calibration again. Worked fine til perhaps 12m or 10m phase. I then heard some terrible noise from the speaker and saw the QMX crashing with all blocks in the display and turning itself off. I tried powering on again, but won¡¯t start now. Just blank display and current protection on PSU kicks in due to over current. I suspect maybe finals are fried with internal short as result? Jonas 7 maj 2025 kl. 23:12 skrev Stan Dye via groups.io <standye@...>: ? On Wed, May 7, 2025 at 01:38 PM, Wiggle Pig wrote: It¡¯s D503 and D504 These are placeholders for diodes that could be placed across the BS170 outputs, as was commonly done with QDX. Hans included them in the design, but has not encouraged installing the diodes, which he believes are unnecessary for QMX. They may suppress spikes, but they also add additional capacitance to the PA, which may affect it adversely in other ways. There were many posts on this list regarding this topic a year or so ago. Stan KC7XE
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Missing Conductors - is it safe to apply power?
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#qmx
I received my 20m-10m QMX kit and am currently assembling it. Unfortunately, the kit I received was missing the three 33pF and the 100pF capacitors (C401, C404, C521, C516). It will probably take a while until I receive the missing parts and I wonder if it is still possible to finish the build and start testing the device (basic tests like: will it turn on etc). Or should I just let it sit and wait? 73, Dennis DM4NTZ
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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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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+ and DTR/RTS like CW keyering
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Hello dear all and devs, Several hams on our side have equipped themselves with the QMX+. Some would like to know if it would be possible to add a few lines of code to the firmware so that when PTT is triggered¡ªeither via CAT or through DTR/RTS emulation¡ªand the QMX+ is in CW mode, it would transmit a carrier. From our tests, this already works in Digi mode, where a tone is sent through the sound card emulation. However, in CW mode, when PTT is sent via CAT, the radio does switch to transmit, but no signal is actually emitted. It might work if the software sent a tone via the sound card, but most CW software assumes that PTT alone is sufficient. This request is therefore aligned with improving compatibility with most CW-capable software (e.g., fldigi in CW mode with PTT via CAT or RTS/DTR). One of the advantages of operating in CW with the QMX+ is also the ability to reduce receive bandwidth, onboard decoding, breakin etc. We believe only a small firmware adjustment would be needed to have the carrier generated automatically, since the radio already enters transmit mode via CAT PTT. Adding RTS/DTR handling would enable a simple and widespread configuration method for this kind of operation. Otherwise, some have considered building interfaces using FT232 chips and optocouplers, but it would be unfortunate to require extra hardware when just a few lines of code might suffice. Perhaps the addition of a CW submenu to automatically enable the carrier when PTT is activated? Thank you in advance.
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Audio level request
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I would like to block Digi mode audio from going to the earphone jack. The audio levels are painfully loud when adjusted for correct usb output to WSJT-X. I am afraid to switch between sidebands or to CW without removing headphones first. Any Suggestions ? QMX+ with 1.02 . de VK6XT
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QMX 1n4007 diodes
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I needed to replace one of the 1n4007 diodes in my QMX (I cut the lead for an experiment) so I went looking for a replacement. None of the 1n4007 diodes at Mouser have the small diameter leads like the ones from QRP Labs. They are all about .7mm diameter where the QRPLabs diodes are more like .3mm. I ended up ordering Vishay diodes with the fat leads. I had cleared the holes with the solder sucker but the leads still did not fit so I used some PCB drill bits to clear the holes and finally got the diode in there. Hopefully the via barrel is still intact. I am waiting for some caps to put it back together and try it. Any discussion about these diodes? My experience is that 1N400x diodes all had fat leads. Thanks, Tony AD0VC
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Tune SWR on QMX+ always shows SWR <1.05
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Hi, I wanted to tune my magloop antenna with the "Tune SWR" tool in the QMX+ menus, and no matter what I do with the antenna, the SWR never goes above 1.04 or so. That cannot be correct, as I'm using a magloop. Any tips on what I'm doing wrong?
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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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Digikey order
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I need to order some parts from Digikey. I though it would be good to order some backup parts for the QMX+. Besides BS170's what are the components that fail most frequently? Also if you have specific digikey part numbers or names that would be great, ss some of the part names match multiple items.
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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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QRP Labs kit shipping status 20-10 FS
The price of success! My Factory built QMX hiband can be in your hands in a week or so. 12- volt build, enclosure, .027 installed. Works perfectly. Email sfab43@ho**ail.com for more info. Steve JS6TMW/AI6KX
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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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QMX+ issues
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My QMX+ was working but when I powered it on this morning the display backlight is not on and the display shows a row of black blocks. Does anyone have any thoughts on where to start troubleshooting. +V or +12v has 12v, VCC has 5.1v, and VDD has 3.3v. I have had some issues with this unit. The 78M33 failed. When I tried to remove it the two small pads lifted. I currently have the 3.3v being supplied by a small DROC 3.3v buck converter. It was working well as of yesterday, I completed several FT8 and SSB QSOs.
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QMX+: low RX sensitifity @ 6m / 22 dB noise floor / 1500 Hz wistle
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Hello, I recently build QMX+ and noticed a huge noise floor and wistling a 6 m. Therfore I measured sensitifity using a signal generator. Band [MHz] Sens [dBm]@Noise+10dB Noise [dB] 1,85 -100,0 0 3,65 -106,0 0 5,35 -107,0 6 7,07 -107,0 0 10,14 -110,0 2 14,23 -107,0 1 18,1 -103,0 4 21,04 -99,0 9 24,9 -97,0 7 28,1 -103,0 5 50,5 -79,0 20 Method: injection of signal Rx frequency + 1,1 kHz Mode: Digi Noise: signal detected by WSJT-X Sens: Noise floor + 10 dB Noise floor is increasing by frequency, but at 6 m wistling and digital noise make RX unusable. Output at 6m is about 2 W at 9V Vbat (12V Version) 1,5 kHz wistle starts at 20 m and is increasing by frequency Using wsjt-X i evalating waterfall diagram: (QMX+ at 50 Ohm) AVE:1, cumulative Noise [dB] : signal by WSJT-X signal in waterfall diagram AU QMX+ freq [Hz] freq [Hz] freq [Hz] freq [Hz] freq [Hz] freq [Hz] Frequency [MHz] Noise [db] Noisefloor 500 1000 1500 2000 2500 3000 1,84 0 0,2 0,2 0,2 0,8 0,2 0,2 0,2 3,57 0 0,3 0,3 0,3 0,7 0,3 0,3 0,3 5,3 1 0,5 0,5 0,5 1 0,5 0,5 0,5 7,04 5 0,8 0,8 0,8 1,1 0,8 0,8 0,8 10,1 1 0,5 0,5 0,5 0,5 0,5 0,5 0,5 14,1 1 0,5 0,5 1,3 2,8 2,1 0,5 1,5 18,1 5 0,8 1 1,8 2,3 2,1 1,1 2 21,1 7 1 1 2,1 2,6 2,1 1,1 2,1 24,9 7 1 1,2 2,7 2,8 2,7 1,3 2,5 28,1 7 1 1,2 2 1,5 1,5 1,2 2,2 50,3 22 1,8 2,5 3,8 4,2 3,9 2,8 3,8 At higher bands 1,5kHz signal is constant and independent from RX freuqency. At 6m additional audio signals are appearing. 6m RF Filter seems to be ok. Any suggestions to detect cause? vy 73 Michael (DF6TV)
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#qmx plus assembly one LP and Band filter at the time
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#qmx
Hi Everyone I was wondering if is possible to assemble only one band filter at the time on a qmx plux rev3, this means I have assembled the all QMX leaving out only the toroids of all the filters, the LP and BP ones. Now next I have assembled only the 160m LP and BP and test the filters. The swipes look normal on the 160m. Next is to test transiting to a dummy load only this band, but I get the swr protection kicking in and no power out. voltages look normal. running a swr plot on 160m shows swr 10 on all graph. The main idea is to tune filters one by one with space for the soldering iron making it easy. I have reviewed soldering of transformer and swr brigde plus the jumper to the bnc is in place. My question is, Is it expectable that the SWR is High when only the filters for one band are on the board or this means something else is already wrong from the beginning. Thank you a lot 73 Azgael
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QMX PLUS
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Hi all I have a qmx plus and I ran 13.6 volts into it on a first time power up it worked for abt 5 min then it shut dow. Then i read about the max of 12v vcc. I am assuming that I lost the buck converter. I have replaced all the sbject transitors that showed bad via the ohm meter still no joy. does anyone of you smart ones have test point diagram fot the buck converter so i can trace it and trouble shoot . thanks you a bunch Joe
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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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