beta 1_01_003 FW strange behaviors
2
I just got back from the Pacific NW robotics district championships where N7BIN and team were competing. There are a couple parks just off the highway near Spokane so took time for POTA on the way to/from. I noticed a couple strange things with the 1_01_003 firmware on my QMX rev 2. At one point, after powering down to swap cables, the display showed USB mode but the rig was clearly in LSB mode. I switched to LSB on 20m and everything sounded normal again. It appears that there is some way for the displayed mode and actual mode to get out of sync. When in SSB mode, I noticed that the SWR meter was swinging wildly into territory where SWR protection should have tripped, but SWR protection did not trip. When in CW mode, it behaved as expected. This was transmitting through a ZM-2 tuner adjusted for 1:1 SWR. Despite this, and the challenge of 5W SSB with a low antenna, the activations were still a lot of fun. 73, Mike KK7ER
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QMX+ points A continuity check to ground question
4
On p25 of the Rev 3 QMX+ manual, there is a check for continuity to ground from three points A. BEFORE installing T501, when checking the three points A, I get about 15 ohms with the DMM black lead on the ground connection, but open circuit (desired) with the leads reversed (ie red lead on the ground connection). Is this to be expected? The 4 BS170's ARE installed. I am troubleshooting a continuity check problem identified after having installed T501 (now removed). Thanks Steve AK0M
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New Chat: QMX Bricked
#chat-notice
A new chat has been created: I have been enjoying the 10-20m QMX for several weeks. I used two 1N4001 diodes to drop the voltage to about 10.5V. I had a beacon set on 10m. Antenna SWR was 1.2. Everything worked great until today. The diodes melted and the QMX is dead. I took the unit out of the case but there was no visible damage. HELP! By: w8mv@... View/Join This Chat Do not reply to this message to post to the chat. You can participate in chats only through the group's website.
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QMX hiband for sale
Factory built 12 volts, works perfectly. I've only made a few hundred CW QSOs. -27 firmware installed. With case $165 plus postage from Japan. JS6TMW
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QMX Build Challange
5
I received a QMX and built it. I've built a number of QRP kits all successfully, but not so for this little guy. I attempted to powered up using a regulated power supply at 7v and 250 mA but without success. In my efforts to get things going, I resoldered every joint and inspected for bridging. In the end, I clearly identified a component (Q109) on the 3v power supply that had a hole melted through the package. I've just order the spare power supply boards from QRP Labs, but don't know where to look for the cause of the current failure before installing and destroying another 3v power supply. Any ideas for me. Regards, Wilson Little (NT5AT)
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QMX+ bias current + output power fluctuating
21
My QMX+ went together really nicely, along with my battery and speaker mods. However, the bias current is varying wildly on TX, also transmitter voltage is indicating low and output power varies. All other tests and sweeps look ok. I've attached a short video showing the diagnostics test on TX. I've replaced C504 as has been suggested and reflowed all joints that looked like they might be dry. I'm a bit stuck now on what the issue might be - any thoughts from the hive mind?
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New Chat: QMX+ assembled
2
#chat-notice
A new chat has been created: Hello, i'm sorry for asking newbie-easy questions. Do i need dummy load, perform any possible calibrations if will receive already assembled and tested QMX+? Can i use built in SWR sweep and meter for tuning my antenna? I'll use it mostly for digimodes. By: Algis Unknown <wiseacre1@...> View/Join This Chat Do not reply to this message to post to the chat. You can participate in chats only through the group's website.
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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)
29
#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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QMX snags epic DX during greyline!
3
Well the QMX masterpiece has pulled off the greatest miles per watt of my life, using my homebrew EFHW. I am still is awe to put it mildly. I worked FR8UA at greyline from Montana for a distance of 10,583 miles on FT8. Thank you Hans for all your hard work on this radio, it's truly amazing! John
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QMX+ front panel pcb too wide
3
Just finished assembling a QMX plus. Went to put in a case and it doesnt fit. The front panel PCB is wider that what is pictured in the manual. It appears that it didn't get trimmed properly by the manufacturer. This is the picture from the manual, the yellow boxes represent the extra parts my PCB have. what would be the best way to trim these pieces off without damaging anything?
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Record number of assembled transceivers shipped in March
2
Hi all I have updated the assembled kits page https://qrp-labs.com/qcxmini/assembled.html In March 2025 we shipped 280 assembled transceiver orders (some containing more than one transceiver). This is a record high number. The waiting time for assembled transceiver orders is currently around 1 month. 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl
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QMX repair
4
When I finished my QMX rev 4, 12v build, it would not mount as a USB drive. I received several thoughtful and helpful suggestions from the community here. Thank you. I followed the suggestions as best I could. In one of the suggestions, Jeffrey Moore, W1NC, was suggested as the go to guy when all else fails. I sent my unit to Jeff and in my experience he is, indeed, the go to guy when you have exhausted your own experience. He fixed my unit and tested it on all bands. He provided me a detailed list of all that he did to fix the unit. In short, he is thorough. He provided such a thorough list of my defects in construction that convinced me I should have ordered a factory constructed unit. LOL If you, like me, have screwed something up beyond your ability to fix it, look up W1NC on QRZ.com and ship your unit off to him. I thank the community for trying to help me and I thank Jeff, W1NC, for fixing my construction problems. Jim Brown, W0RLD
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QRP Labs kit shipping update
Hi all During my absence on family vacation last week there was a major storm last Thursday, a lot of rain and thunder and lightning. After one close-by strike my colleagues reported crackling and sparking on cables in our office, and since then we have been without internet... the ISP say the modem is working fine (they test it from their end) but we tell them it isn't actually delivering us any internet. Anyway regardless of that, today I woke up and figured out how to USB tether my cellphone to the PC and share the internet to the PC. And got my shipping colleague doing the same thing via her iPhone. So 2 of our 6 QRP Labs office computers (which are the most critical two) are back online while we wait for someone from the ISP to visit. We are now working on catching up on the shipments from last Thursday to today. Meanwhile after all the crackling and sparking my colleagues thoughtfully unplugged my antenna. Full marks for effort... but the damage was evidently already done by that time: when I returned from vacation and switched on my QMX+ the thing popped and current went to several amps... I replaced the four BS170 PA transistors (one of which was visibly cracked); still not getting correct power output and performance I realized I need to replace the Q508 Tx/Rx transistor which had also apparently taken a hit. After all that, happy to say everything is back in order, the radio is working properly once again! Meanwhile: we ran out of dummy load kits, and the 1.000 new PCB's are on the way via FedEx. They are going through customs processing in Izmir today and after that the imports normally reach me about 2-3 days later by road via the domestic courier who are the local FedEx agent. So some of you who ordered a Dummy load kit might be wondering why your order didn't ship yet, this is the explanation, please wait a few days. 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl
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QMX+ messages are loose some characters while sending
#anomaly
#cw
#messages
#missing
#QMXplus
hi, may i`m wrong with some config, but sending cw from stored messages isn?t possible without loosing some characters, as like as "cq de df4bj" may ends in "ca de dfuba" or something else. Same behavior if sending from logging programm via cat. Did i don`t have correct configs or is that an known issue? I have installed the v1_01_003 , but going back to a non ssb fw doesn`t help. any suggestions ? vy 72/73 de Udo DF4BJ /qrp
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750 Hz Square Wave from #QMX Speaker while Transmitting
2
#qmx
#beacon
Does anyone else hear this constant 750 Hz square wave through the speaker while the QMX transmits a CW, FSKCW or WSPR beacon message only when the QMX is in USB or LSB mode? While the QMX is in CW or DIGI modes the speaker remains silent during beacon transmissions . Watch my video at https://www.youtube.com/watch?v=d-me0UrO1dQ QMX+ transceiver with Firmware 1_01_003
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QMX shutting off at 10.5V
10
Hello all, My QMX suddenly shuts off at around 10.5V. Is it normal ? I can't recreate it but last summer I think had it giving me high voltage warnings when in fact, voltage was low even if I didn't understand at the time that the radio was suddenly shutting down when voltage is low (/g/QRPLabs/topic/110264408#msg135921)... It is problematic for me as I use a nominal 12V drill battery that goes down to 10.5V relatively quick before stabilising there.... I've already fried the SMPS once so I have a new set bought in April 2024. I am not too sure how to investigate this further. 73, Yannig - F4IUJ
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Internal mic seems to be working?
8
#qmx
#ssb
I've just tried transmitting SSB using the internal mic to a dummy load, with my K2 next to it to receive the SSB signal and record the audio. Although the background noise was loud whenever I pushed the PTT button, my recorded voice was also loud and clear. I set the mic gain to 60 and compression to 10. So the internal mic is already useable I guess? Anyone tried the internal mic to make a real contact? Yoon KM6KJI
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Thanks Hans!
Just finished "building" my QMX+ and everything works as advertised! Got lazy and tried a couple of FT8 contacts on 20. Kentucky, Indiana and Brazil in short order on an end-fed dipole. I'm impressed, Hans. Thank you for the contributions you've made to the community. -- Brent DeWitt, AB1LF Milford, MA
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For Sale
3
I have a nice QMX+ and QDX for sale. The QMX+ has a case and GPS unit installed. Work good. Typical power outputs. It has the SSB software but has nor been calibrated. $185 shipped to CONUS (Lower 48) The QDX has the case as well and also has the typical Power outputs. $90 Shipped to CONUS Email markf1952 at hotmail dot com N5MF
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Qmx ft8 linux
2
I had been trying to figure out why I could not make any ft8 qso's. Seemed wsjtx was connected, got audio in my ear when transmitting. Would change radio bands. Turns out I missed when reading the manual, make sure computer volume is set to 100%, and no more. Mine was at 150%. Working great now. It always seems to be something I did wrong. Hope this helps someone.
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