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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

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.

Park US-3843 today, central NC. Low humidity after yesterday's storms. Slight breeze. QMX built for 9w Dork regulator DROK Adjustable Voltage Regulator... https://www.amazon.com/dp/B089ND7PTH?ref=ppx_pop_mob_ap_share Bioenno 9v battery SOTA Beams Bandhopper Palm pico paddle Why I love this rig: even though it is menu-driven, it seems SO INTUITIVE that it doesn't seem difficult to do what I want. Hans must have done some serious human factors analysis with the rig. Also, the receiver is outstanding. I made 24 QSO in 45 minutes on 20. The beacon CW message capability is superb. Thanks to all for the Drok regulator suggestion. And thanks to Hans!! Mark Lunday wd4elg@...

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

The following report is for the latest (SSB-)firmware 1_02_000, 80-20m band version and SSB-mode. When transmitting in dummyload or resonant antenna, the same occurs: At the beginning of the transmit the SWR-meter of the QMX overshoots to maximum level for a very short time (about half a second) and then goes down to the real SWR. Generally not a big problem. But on 80m band the SWR protection kicks in every third or so TX-cycle. I think it is because of the overshoot(?). The other 4 bands do not have that problem Has anybody experienced the same?

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

... 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

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

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