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Has anyone tried replacing the USB B connector on the QDX (or any of the other Q*X radios) with A USB C breakout board like this one: https://www.adafruit.com/product/5807 Either with or without using the USB C for power delivery? Thanks, Nate KV4RD *** Nathaniel Drexler

Hi Hans, Is there a maintained Feature Request list available somewhere where we can check if what we’d like to see has already been asked for, and perhaps add a vote? I know posts can get lost in the volume, and I expect that is why there was no answer on my question on having variable TX power available as a setting (/g/QRPLabs/message/143397), but I don’t want to bug anyone, so if there was a tracker we could look at, it might save you getting duplicate requests or being bugged by people like me :-) Love the pre-built QMX, am going to get a QMX+ kit to have a go at… 73, Stefan MI0PYN

Details about my QMX+: Board rev 2, firmware rev 1_00_027, wired for 12v operation (RWTST output transformer). Running it from a Buck converter set to 10 volts. I recently completed the assembly of my QMX+ kit, and It’s suffering from several problems (low output power: ~2.4 watts, low receive sensitivity, most of the filter scans have the right “shape,” but the levels are low, the IQ scans look fine on some bands, but they are just noise on most bands). Rather than trying to cram everything into one thread, I thought I’d break the issues up into separate threads. Anyway, the problem for this thread regards FT8 (WSJT-x) reception when the radio is in digital mode. When it’s in CW mode WSJT-x can receive and decode FT8 signals. But the radio goes quiet as soon as I switch to the digital mode. I’m having this issue on every band. In the QMX+ “System Config.” settings, IQ Mode is Disabled, Sideband is USB, and CW-R is off. I’ve also disabled VFO B and the Split mode. All communication between the QMX+ and WSJT-x is working fine. My WSJT-x is version 2.7.0 (64 bit) and I’m using HamLib version 4.6.2 (I’m not using the file that is bundled with WSJT-x; I downloaded the DLL separately). The computer is Windows 8 (64 bit). I did some experiments using my FT-817 (connected to a dummy load) to transmit CW to see if/where the QMX+ receives this signal (the two radios are side by side). The QMX+ was set to the band’s “FT8 Watering Hole” frequency (14.074, for example), and I monitored the reception on WSJT-x. To simplify the explanation, I’ll call it “Digital Working Mode” and “Digital Not Working Mode.” Here’s what I’m seeing: Digital Working Mode… · I can hear over-the-air FT8 signals, they are displayed on the waterfall, and they are being decoded. · The CW signal from my ‘817 shows up on the WSJT-x waterfall. · As I increase the transmitted frequency (from the ‘817), the “tone” goes higher. For example, if I transmit on 14.075, the signal appears at the 1000HZ line on the waterfall. When I increase the transmitted frequency, the waterfall mark moves up (higher tone). When I decrease the transmitted frequency, the waterfall mark moves down (lower tone). Digital NOT Working Mode… · As soon as the QMX+ enters this “Digital Not Working Mode”, no signals are being heard. I can’t even hear the signal from my FT-817. · If I DECREASE the FT-817’s transmitted frequency to 14.073 (1000 Hz BELOW the QMX+’s dial frequency) the FT-817’s CW signal appears on the waterfall at 1000 HZ. · When I increase the transmitted frequency, the waterfall mark moves DOWN (lower tone). When I decrease the transmitted frequency, the waterfall mark moves UP (higher tone). This behavior is opposite from the CW mode and from the “Digital Working Mode”. It almost seems as if the QMX+ is trying to receive LSB instead of USB? Switching between “Digital Working” and “Digital Not Working” Modes…. Clicking WSJT-x’s “Tune” button, or trying to answer a CQ, or even clicking a selection from the WSJT-x “band” drop down box (that’s on the left side of the screen) causes the QMX+ to stop receiving the FT8 signals. It seems that any CAT command puts the QMX+ into the “Digital Not Working Mode”. As soon as a CAT command is sent from WSJT-x, the QMX+ stops receiving the FT8 signals. The dial frequency is still on the “watering hole” frequency, the radio is in the “receive” mode, but no FT8 signals are heard or decoded. To get out of this “Digital Not Working Mode”, all I have to do is to enter and exit the QMX+’s menu (it doesn’t matter which menu level is active). Simply by holding the left button and then exiting by tapping the right button allows the QMX+ to receive normally (in the digital mode). Any thoughts? Shouldn’t the received signal on the WSJT-x waterfall go “up” (higher pitch) when the transmitted frequency is increased? When it’s working like that (either in CW mode or in “Digital Working Mode”), I can decode signals. Why does entering/exiting the menu correct the problem? Has anyone else seen anything like this? Thanks much, Larry (WA2VKG) S

I just hooked my scope up to the drain of one of the PA transistors in my QMX+ and kicked off a 160M Phase cal (O button). I am seeing 120 volt spikes during the cal. Here is a link to a screen shot from my scope: 160PhaseCalGlitch.jpg This is going to fry some BS170s for sure. Tony ADoVC

Just did calibration on month old factory built and now the rf out is half or so of before in ssb or digi mode. Did I blow one or more pa. Who was the guy with the cape that was doing repairs and checkups :) What say ye? wd5eed ps: it did shut down when it got to the 11m cal. -- 73 ChuckR

Hi all Yesterday we had a total of 7 visitors to QRP Labs from Mugla Deniyap (technology workshop) and Mugla university. Only one (Necati TA7MNA) is a radio amateur. We had a great time with hours of discussion about QRP Labs products and amateur radio in general. Then we arranged a workshop activity to prepare and launch two U4B tracker balloons, which we have called Deniyap-1 and Deniyap-2; these fly with callsigns G0UPL and TA7MNA respectively. By the time we were ready, and had driven to put helium in the balloons, it was evening and already completely dark. We launched from a nearby football field by the light of car headlamps and mobile phones. Of course as it was dark we had no telemetry from the balloons and no idea of success or failure until the following morning. But surprisingly both Deniyap-1 and Deniyap-2 showed up near Suez, Egypt having crossed the Mediterranean overnight. Deniyap-1 (callsign G0UPL) suffers a broken antenna (the wire snapped during launch) so far fewer reception reports. Deniyap-2 has crossed the Northern part of Saudi Arabia today and is almost at the Iraqi border. I prepared a web page which includes lots of photos of our activities, construction and launch: https://qrp-labs.com/u4b/deniyap.html 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl

Hi everyone, A quick little question: After receiving my fully assembled QDX, I noticed that it is not working correctly in the 20m band. As soon as it goes to TX in the 20m band, the LED flashes twice in quick succession. The QDX is then blocked and I cannot access it with wsjt-x (reports CAT error) or via a terminal program. Only after disconnecting the power supply and plugging it back in again is access possible. The error does not occur on 40m. Everything works fine there. I have tried the following: 1. Laptop with Windows 10 2. Laptop with Windows 11 3. Various USB cables 4. Older Firmware Versions Unfortunately, everything was unsuccessful. I hope someone in this group has an idea of what I can do and look forward to your feedback. vy 73 de Andree, DG7DK

The following items have been added to the Files area of the QRPLabs@groups.io group. /QMX Menu Reference.docx By: Paul K7VIQ <de.k7viq@...> Description: A QMC /QMX+ reference guide doc for those wanting a copy or to improve and update to keep current.

This build although tedious has been challenging fun! I need HELP, I think I used too much wire when winding the T401 trifilar toroid. Is it possible to use #26 wire (I have a spool) instead of the #28 wire for the L511 Low Pass Filter toroid or should I purchase more #28wire? 73, John - W7OTD "people ought to saunter in the mountains - not 'hike!" -John Muir

I waited for and yesterday installed the 1_02_000 firmware. I did a bit of tinkering with the EQ to get some more emphasis in the mid-range (and worth noting that when I do live sound at folk dance events, I always cut back the bass and emphasize, not too much, mids and highs to improve intelligibility of the dance leader, just as Hans suggests). And I made 4 SSB contacts on 20 meters with some Italian stations in a contest setting .... running about 75 watts with the QMX+ and my HR-50+ amplifier. Worked great. Thank you, Hans ... you are a wizard! One glitch ... I cannot get VOX to work. I'm using one of Erik Larsen's microphones, which clearly works fine in PTT mode and sounds OK. I set microphone gain using the built-in Mic Test ... goes red on just the loudest peaks. On USB, speaking into the microphone apparently triggers the VOX, but it then cycles on and off until I manage to get QMX+ mode out of USB over to LSB. LSB doesn't work at all ... speaking into the microphone does not trigger VOX. Input device is set to "External Microphone". And I'm using TRS (stereo) 1/8" mini cable between the microphone and the QMX+. Any hints will be much appreciated! Thanks - Bruce K1FFX

Folks, prior to going to the most recent firmware on one of my QMX+ rigs, I ran PuTTY and documented my power out into a dummy load on each band. Then I installed the 2.0 firmware and ran another PuTTY session, noting the power - it was exactly the same. Last night I ran the calibration procedure - geeze, that took forever! Anyway, after doing that I did a mic gain adjustment and went up to the 40 meter phone band. OMG - a bazillion stations - the 7 district QSO party in full swing! Started adjusting my manual antenna tuner and noticed that my power output was much lower than it had been. Looked like less than three watts now. Tried calling a station but no reply. So, I fired up my recently built WA3TFS 20 watt amp and was successful working several stations before calling it a day. This morning I started PuTTY and checked power out on each band. Sure enough, the result was that each band is now showing 50 percent less RF out than before. Not cool. I was thinking about doing a factory reset to see if that would cure the issue. Or going back to 0.027 firmware. But that would mean doing that hour long calibration routine again at some point. So, any thoughts about this problem? Have others seen this after doing the calibration run? And if so, what was the resolution? -- Jim / K7TXA Eagle, ID SKCC 10447T BUG 301

Hello All, QMX Mid band I am not getting but less than a .5 watts out with mic gain all the way up. this is going into a dummy load input is on external mic, power is 9v for 9v build, mic is the one Hans has done the testing with brand new from Digikey. CW works just fine 5 watts out on all bands I ran the calibration in firmware 1_01_007 but have update to 1_02_000 to see if that would fix problem it did not. Any suggestions as to where my problem could be. thanks in advance John Dunn KJ4WSR

So built the qmx with no issues installed Hans latest firmware completed full calibration. CW tests were fantastic no issues. BUT! Ssb is not behaving. Built the small electret microphone and tested with quite a lot of distortion tried various adjustments up and down to no avail. I have a suspicion that it may be the electret which is -50db . 1-10v The one everyone is using is -25db could this be the issue.?? I can't source the -25db one here. Currently doing another recalibration. Any suggestions are gratefully accepted :)

I have an odd situation here with my 12V QMX+. I could transmit normally on all bands with a 9V power supply. But at 12V when I transmitted on 12m (24.910 MHz) the current draw was quite a bit higher than on the other bands. My power supply's current limit was set at 1.0A and it hit that. All other bands drew less than an amp. After transmitting at that frequency the receive current had jumped to 300 mA (previously about 100 mA) and all the other bands transmitted about half the output power they had before. I replaced the finals and it happened again. Transmitting on 12m at 12V caused a failure in the finals. (Possibly Q507 as well. I get no RF output at all on any band now.) Any ideas on what might cause that one band to zap the finals? I've looked over its lowpass filter and don't see any visible shorts, and the inductors have the correct cores and number of turns. I was able to transmit on 10m before trying 12m and it seemed to work, although with less power out than the other bands.

Just finished my QMX+ build today, and after tracking down one bad solder joint on L502 I’m up and running with good TX power. I do see RF Filter scan that shows both 40m and 20m peaking off-screen to the right (high freq side). It’s like the whole curve shown in the manual is shifted about +3-4 MHz. The on-band level is about -10 for both 40m and 20m… but I don’t see any change when spreading or compressing coils on L403 (that should be the RX filter for 40/20 right?). Not sure what to try next or if it even matters much. Other performance seems good and tests report results as expected. Thanks! Andy

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