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WARNING!!! Running the SSB calibration in automatic mode has the potential to burn out the finals. I've read at least 1 other thread where running the SSB calibration resulted in failures in the output stage. I now have a non-working QMX+ because of this. I replaced the blown final, but there is still another problem in the transmit circuit. When I attempt to transmit from the diagnostics screen, I get 0 output power. If I put a scope on the gates of Q503-Q506, I see what I assume to be a good signal, it's at least at the right frequency. Q507 heats up when attempting to transmit. I also note that the duty cycle for the 5V SMPS jumps up to around 75%, I assume because it's trying to push out so much current. I'm kind of stuck here, I have the tools (meter, scope, rework station), but I'm sorely lacking in troubleshooting skills for this type of problem. This was my second QMX+ build, and I was ecstatic when it worked flawlessly on first power up. I made some contacts on it, and decided to get it ready to try SSB. Kicking myself for not reading more before diving in to the calibration or I might have not used the automatic option. I'm going to go read what I can find regarding an issue like this. If anyone can offer any troubleshooting tips they would be greatly appreciated. I'm looking for what to check, and what a reasonable result would be. It's built for 12 volts. Currently (pun unintended), the supply voltage drops to about 7 volts during transmit when I have the power supply current limit set to 700 mA. I checked and the unit seems to be able to sink as much current as I dare feed it. My first unit is on its way to Jeff. I'm going to work through this one myself, I hope. Thanks and 73. Andy WB9YXA

I fired up my QCX 20M for the first time in over a year. I didn't tune the antenna. I sent a few dits and dahs, then when I checked I was at 2:1. I am not transmitting into a darn near 1:1 and only seeing about 1.3 watts. I know the QDX is very sensitive to SWR. is the QCX also, did I likely blow my finals? or is there a alignment that may need to be done since it has been so long since it was powered up? Bob

I am using SSB ver 009 firmware ATM. Have noticed the audio levels into WSJT-X appear to be down by about 10dB.. Having trouble getting enough signal to get into the green even with the band config levels increased to 76 - 79

The internal Mic doesn't work. But let's not throw out the baby with the bath water. To this end I built a little simulator to test how a "Little Hole" works and if that can be retained in a future revision of QMX.....or if it is a bad idea. In short, I drilled a small hole 1/16" hole in plastic box about the same size as a QMX and placed a working mic in the box. To my delight the laws of air pressure worked and not only does the result sound good, it may even be better than a foam muff. It tends to buffer the sound. Hans had a good idea, he just 'F' up the design. No shame there, we all do that. The real shame would be discarding the IDEA.

Firstly, this is an amazing kit and the software development has been outstanding. I, for one, am very grateful. Three comments follow: - I have noticed that the band TX inhibit does not take effect, in SSB mode (USB/LSB) until you cycle through all the other modes and return to it. Also Errata in the operation_1_02_000000 manual, page 29. Passband 100 Center 600, 650, 600, 750, 800, 850, I think should read: - Passband 100 Center 600, 650, 700, 750, 800, 850. Lastly, I wonder if an SWR bargraph could be added to the Hardware Test, SWR measurement screen? This would help in antenna tuning in the field. Again thank you Hans. Mal

Hi all, Yesterday, I finally found the time to finish building my second QMX (Rev.2, 10m - 20m). Initial setup was easy, and after loading the latest firmware, all tests ran smoothly. Today was its first use, which was also successful with a few FT8 QSOs. But after about 3 hours, the QMX said goodbye with a loud pop. C107 looked like the picture below: https://www.bitquell.de/nextcloud/index.php/s/cf9tbs844aW2mgq I can't identify a cause for this defect. The QMX is built for 9V and was powered by the stabilized 9V output of a TelentCell LF4100. The antenna was a precisely tuned vertical. Will replacing C107 be enough? I'm worried about Q107. Could the burn that can be seen in the picture have been caused by C107, or is Q107 also defective? 73, Joerg DG0JDE

I just purchased the QRP Labs Clock kit along with the GPS unit, the QLG-2. Assembly was pretty darn hard with about four parts to solder up, but I managed to get them all mounted and the unit works well. My question is How do you program the clock to display anything besides the stock GPS display? It seems that the Clock kit that I received does not resemble any of the Clock kits listed on the web page. It does not have the two programming buttons and my feeble attempt to communicate with it was not very successful. The new Clock kit has none of the pats that are listed for the older designs on the website. The only parts I had to put in either kit were a contrast pot, a few headers, and a USB receptacle. I can talk to the GPS receiver and get the firmware version, but I have not been able to address the clock to show Maidenhead grid squares or anything else. That 6 digit Maidenhead info would be a nice feature for me. It seems that the Clock Kit shown on the website is not the clock kit that is being shipped and I am not sure how to proceed. 73 Dave K1WHS

Ok, just installed linux mint , installed js8call and flrig. the three serial ports show up but flrig not talking to qdx. Way way in the past there were some comands i had t issue to get things rolliing, now old and need some memory help :) who can give a list of some sudo ?????????? ????? ?? to issue to insure audio, and other nessasary things work and not go bump in the nite.... here is me begging for help -- 73 ChuckR

Does anyone know the full part # and manufacturer for the 2 x 3 pin header connector 90 degree plug (male) on the QCX+? One of mine is missing. Jim spikes, N4KH

Hi, I tried to use a standard Baofeng micro , the one with a small loudspeaker inside that is not usable with QMX. I have done the easy mods to make possible using this mike with the QMX. No a big issue ... Tried also the Microphone Test tool in the QMX sw, and the mike seems ok using only 40 db for gain. BUT, if I listen with another radio the modulation is very bad .. !! Possibly the two radio too close ?? Unfortunatly, if I talk ,does not seem to exit any RF or just a little bit, from the QMX ( I have a swr/wattmeter in line..). In CW all is ok, in SSB Baofeng micro seems no good. Have you tried the Baofeng Micro ? I guess every body owns one of this mike that why I am asking. 73 de angelo i1jck

Hello there , New Ham , New QDX user where the radio has been donated to me by TRAC friends in Istanbul. I reached Australia , Antarctica and Greenland with a 5 volt pc supply and an untuned cable antenna dropped from a window on a concrete wall. Now , I want to transmit a few hours daily in - digital radio mondiale - mode and I will make a pirate radio. Can QDX help me ? Umut TA2JCO

Ooops, My QMX should read my QMX+. 73 Ian G4GIR ----- Original Message ----- From: Ian G4GIR via groups.io <jean.frith@...> Reply-To: <[email protected]> To: <[email protected]> Sent: 03/05/2025 10:46:17 Subject: Re: [QRPLabs] 6m Phase error vs DAC Just checked out that Wiki article. /g/QRPLabs/wiki/39506 Hans quotes:- "Note that on QMX+ I have never seen this occur;" Hans this is happening on my QMX! The last kit I purchased from you, the previous two kits don't have this problem Can I claim a first!! Lol. 73 Ian G4GIR ----- Original Message ----- From: <DH8WN@...> Reply-To: <[email protected]> To: <[email protected]> Sent: 02/05/2025 16:33:58 Subject: Re: [QRPLabs] 6m Phase error vs DAC Ian, there was a discussion about this some days ago. Please read QMX QMX_plus SSB Calibration and Predistortion from the QRP Labs wiki to find the relevant text, about 'calibration not possible' especially more at the end. 73 Ludwig.

I had been puzzled for a while because I couldn’t get the device to transmit on the 20m band only. Again today, I played around with various settings, hoping to fix the issue. While modifying different parameters in Terminal mode under the Config menu, I discovered something unexpected. It turns out that if I set 'Japanese band limits: ENABLED' in the Configuration, it restricts transmission to the 20m band only. When I switch it back to the default setting 'DISABLED,' transmission becomes possible on all bands! What a surprise! I really think this should be clearly mentioned in the manual. With this, I now have a lineup of two units — the 5-band version (80–20m) and the Hi-Band version (20–10m). I couldn’t be happier! JA1TLH/Taka

I took the PC Board for the QCXmini out of the plastic envelope and after inspection found that C39 had broken off, probably in transit. There was a CAP in the box, so I soldered it back in place. I am afraid, however, that C39 was damaged, since it appears to be missing the silver metal end on the right side. It may be that it is only the solder packed up agains the broken end and it is not making an electrical connection. I do not have any .1uF caps of similar size to replace. Should I continue with the build, and find out if it is broken when I finish the build? Or should I try to find another one before moving on? There are several imprints of other SMD components on the bag that the board came in, so I suspect the problem is that the board was backed too tightly in the box, rather than an assembly problem. Box arrived seemingly undamaged from MO. Thanks for your thoughts. Phil, K3UT

Hi all I updated the SSB beta testing webpage of the brave, here: https://qrp-labs.com/qmxp/ssbbeta.html and released firmware version 1_01_007 to it. This fixes one more typo I found in the USB compound device configuration. I carefully checked all 440 bytes one by one in all three configurations (1, 2 and 3 serial port). I believe in the 1-port configuration the configuration is byte for byte, identical to 1_00_027. Waiting for Ludwig to confirm any issues or not with WIn 7. I booted my PC into Windows 10 on the old HD and all three serial ports worked properly, and audio too. 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl

President Trump has signed an Executive Order that ends the tariff/duty exemption on small value shipments (i.e. < 800 USD) sent from China to the US. It is not made clear if this change will apply to shipments from other countries as well. This will certainly impact those of us who purchase PC boards, electronic components and modules, and equipment in pursuit of our hobby. 73, Ben K0IKR Here is text from the US government: “Today, President Donald J. Trump signed an Executive Order eliminating duty-free de minimis treatment for low-value imports from China…” ” Following the Secretary of Commerce’s notification that adequate systems are in place to collect tariff revenue, President Trump is ending duty-free de minimis treatment for covered goods from the People’s Republic of China (PRC) and Hong Kong starting May 2, 2025 at 12:01 a.m. EDT. Imported goods sent through means other than the international postal network that are valued at or under $800 and that would otherwise qualify for the de minimisexemption will be subject to all applicable duties, which shall be paid in accordance with applicable entry and payment procedures. All relevant postal items containing goods that are sent through the international postal network that are valued at or under $800 and that would otherwise qualify for the de minimis exemption are subject to a duty rate of either 30% of their value or $25 per item (increasing to $50 per item after June 1, 2025). This is in lieu of any other duties, including those imposed by prior Orders. Carriers transporting these postal items must report shipment details to U.S. Customs and Border Protection (CBP), maintain an international carrier bond to ensure duty payment, and remit duties to CBP on a set schedule. CBP may require formal entry for any postal package instead of the specified duties. The Secretary of Commerce will submit a report within 90 days assessing the Order’s impact and considering whether to extend these rules to packages from Macau.”