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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

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

Unbelievable - I've been doing firmware upgrades on all my QMX, QMX+, etc. rigs on this Mac Mini since the dawn of time - no problems. Well, tonight I downloaded the new v2.00 firmware and was going to update one of my QMX+ rigs and give it a whirl. No problem downloading the file. he problem is that now my Mac Finder refuses to see the QMX device. PuTTY has no problem connecting to it; MacLoggedDX has no problem connecting to it. But unless Mr. Finder see it, there will be no way to move the new f/w over to the radio. I've even re-booted the computer - no joy. I have not changed anything on this computer nor have I done any system updates. Any suggestions? -- Jim / K7TXA Eagle, ID SKCC 10447T BUG 301

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

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

... by supplying 30 Volts by mistake. :-( . It generated an ugly smell. The QMX plus is now completely dead. When opening the case I saw that a component next to the DC connector was cracked and deformed. I also smelt real bad and is labeled "LG". Whatl else might be damaged - or is it FUBB? In which case I might have to order another kit.... (?) 73, Holger, Dk4LX

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

Hey all! I’m not saying it would be an ideal situation or anything, but does anyone know if/when we will be able to use the onboard mic for ssb operations? I really love the portable nature of my kit and don’t mind using the onboard mic. Thanks! 73 Jeff KB3TVP

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

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 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