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Hi all I have just built and finished my first QMX+ and it worked first time well impressed. Just one question on the power output which I am measuring into a dummy load. On 160m I am getting 7.2w, 80m 7.3w, 60m 6.5w, 40m 5.6w, 30m 5.5w, 20m 5.2w, 17m 4w, 15m 4.7w, 12m 2.8, 10m 3.5w 6m 2.8w so dropping from 7.2w to 2.8w is there any way I can “smooth” this out a little, drop 160m down and increase 6m ??? Thanks For any pointers Paul G0HEU

I either got the wrong enclosure or the wrong main board for a QCX+. The board is much wider than the enclosure. There is a line on the board which is the size the board should have been, but nothing mentioned about cutting the board to make it fit. Besides I don't have the tools to cut it. Instructions say it should slide right into the enclosure. Anyone else experienced this. Other than one capacitor missing this is the only problem so far. ++

qmx with win10 laptop. 2.7 wsjtx when configuring radio it allows. me to select qrplabs qmx. but does not like and. selection for audio what do i need to do to get digi modes/ft4 working? does anyone have the. wsjtx settings? tnx Niece

Hi all I just updated the QMX SSB Beta firmware page with release 1_001_002 which fixes a number of reported bugs, as follows: Bug fix: Update year to 2025 on terminal and LCD splash screen. Bug fix: Incorrect percentage completion status in phase error Calibration. Bug fix: Changes to SSB drive level did not take effect until leaving config. Bug fix: SWR protection was enabled in SSB even when SWR was disabled in menu! Bug fix: CW memory keying activated with Tune DblClick during SSB mode. Bug fix: Hardware tests / Audio sweep wasn't working. Bug fix: Lockup when entering VFO modes menu on terminal. Thank you for all your support and testing! I am extremely pleased with how well SSB firmware is working for many people. 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl

I don't know if any of you has noticed anything similar: while performing the SSB calibration on a band-by-band basis (using the "O" option) I noticed that at the end of the USB/LSB IMD Optimization step of each band, the power out is not put back to zero. I read between 0.5W and 1.2-1.5W on some bands, and again, this is after the IMD optimisation has ended for that band. If I CTRL+Q, then power is reset back to zero. If I get back into calibration, power is still zero. If I do calibrate another band (still with 'O') , the calibration succeeds but at the end the PA is not shut down completely. Now, I think this is hardly enough to put the finals under any substantial strain, if it stays like that for a couple of minutes at most. But I wonder if the few cases of fellows who "left the calibration running and went out for a walk" and then found their finals toast could not be due just to this glitch, i.e., the PA remaining keyed for several minutes, even at lower-than-max power, which might be enough to cook them up, under certain constraints. Has anyone else noticed this? I guess a consistent set of measures of this effect (if it is not just in my QMX+ specimen) might help Hans pin-pointing the issue when he is back from vacation. Hope this helps. 72/73 de Enzo M0KTZ

After a factory reset my QMX+ runs fine for hours running wspr. If I attempt to change parameters through the front panel...turn on clock...dot delim etc it will lose audio connectivity to wsjt and through headphones. Factory reset and reboot wsjt does restore things back to normal. Perhaps I should not try to customise anything whilst under control of WSJT?

Decided that seeing I have the GPS installed, to revisit beacon mode. Setup all the parameters including frequency 14097.200. Well it seems to Beacon OK...I can see that it is transmitting. Problem is ...it is not on 14097.2....in fact I have no idea if it is even on 20m. Bit of a glitch here ? de VK6XT

Hello Hans! My QMX works great with 1_01_003 firmware. I've calibrated it and SSB reports are very good. Thanks! Few problems: 1. Wattmeter indicator looks like very slowly responding to actual power in antenna. As if it is averaging for couple of seconds... 2. When I use my usual PA with 1.3 input SWR (measured with NanoVNA) QMX tends to stop transmitting in several seconds due to SWR Protection. And SWR meter displays some big figures which do not exist in reality (checked with my standard SDR transiver and NanoVNA). 3. Nothing changes on PTT output during TX. 5V stays on the ring and 0V on the tip.

https://www.allaboutcircuits.com/technical-articles/introduction-to-the-feed-forward-linearization-of-rf-power-amplifiers/?user_mcid=3b7c12b4be

On 3/28/25 I had a CW practice / rag chew session on 20 meters. I worked three stations. I even worked some DX: Date / TimeCallBndFrequencyModePowerRecSntNameSPC#CommentsOff3/28/2025 14:00WV7M2014.055CW100229229MikeMTK3 at 100 watts 100 ft sloper doublet3/28/2025 13:05M0NJH2014.043CW100229229NeilEnglandK3 at 100 watts 100 ft slopping doublet3/28/2025 14:05K5AX2014.038CW100599599TomTXK3 at 100 watts 100 ft sloper doublet14:25 Conditions were OK with QSB on some stations. SSN = 72, SFI = 153, A = 33, K = 2. My next CW practice session will be March 31 at 09:00 EDT / 13:00 UTC on 20 meters. Anyone and everyone is welcome. This practice is intended for operators who are new to CW or they need some practice. IT DOES NOT MATTER HOW POOR YOUR CW IS. Mistakes are OK. Poor fists are OK. Slow speed is OK. Really slow speed is OK. This practice is meant for you to improve your CW. I will do my best to adjust to your skill level. Operate at any power level. If several stations show up, I will operate as a round-table control station. I will do it as a round-table so everyone gets a chance to transmit. Please listen to my directions. Details: Date - March 31 2025 Time - 09:00 EDT 13:00 UTC Band - 20 Meters How to find me - I will find a clear frequency and call CQ. Go to the Reverse Beacon Network and search for my call sign AB8DF. That will tell you what frequency I am on. Tune your station to that frequency and if you hear me give me a call. If there is a QSO in progress, please wait for a break in the action. Then send your callsign. If I hear you, I will invite you to join the QSO and start a round-table QSO. Reply to this email if you have questions. IT DOES NOT MATTER HOW POOR CW IS Ed AB8DF

Hi, I installed the 1_01_003 beta firmware yesterday and I am amazed at how it has transformed my QMX+ (rev 2 board). I am, however, perplexed at the fact that the SSB audio is distorted (on another receiver) only on 20M. This only occurred after calibration and the audio becomes absolutely clear again after disabling the phase predistortion. All other bands have good audio with and without predistortion, and the RF output is within normal limits on all bands, although 20M is a little lower than others at about 3W. I am using a 12V stabilised PSU and a good dummy load, via a Bird isolator, giving me a solid signal into my receiver. Trying to think of an explanation made me consider that the LPF used for 20M (LPF 3) may not present a good load to the PA, so I looked at the LPF sweep using PuTTY. Here is the sweep for 20M: The 14MHz line is in a less than ideal part of the curve, whereas the bands which share this LPF are better placed. Is this significant? The phase calibration sweep for 20M also looks odd and is different to the others which are all nice curves (except 160M which sounds fine!): This is the 20M USB IMD sync optimisation curve, the title of which has been overwritten by the asterisks of the curve. The 20M USB curve looks identical: Here is the adjacent band 30M curve for comparison: Everything on the board looks good and the radio otherwise works perfectly. I am perplexed at why only one band is distorted (it really is unreadable) yet 160m, which has similar calibration curves but a great looking LPF, Sounds OK. Any ideas? The simple answer is to switch off predistortion, but that doesn't solve the problem! 73 Ellis GM4GZW

Hi All, Just completed building my third QMX+ (the first two were quite successful) and I've come upon an issue that I need help with. The rig appears to work as advertised: receives well, GPS works, RF output levels are acceptable, everything works great except.... when I key down I hear what sounds like a machine gun. It is not there during receive - only when I transmit. Not real loud, but loud enough to be annoying. Happens on all bands, with AGC on or off. Any idea what might be the cause, or where to start looking for it? -- Jim / K7TXA Eagle, ID SKCC 10447T BUG 301

We had nine folks join the MI QRP Zoom Chat on 27 March. Please join us Thursday April 03 (and every Thursday) at 4PM Eastern for the Michigan QRP Club weekly QRP Chat where the main topics will be QRP and other ham interests. New hams are encouraged to participate and ask questions. It's fun, it's easy, and it's free. You only need a computer, a smart phone, or a tablet that can connect to the Internet. OR if you can't be close to any of those you can join by audio with any standard phone. Just follow the directions below. No software needs be loaded or installed. Anyone can join and non members are welcome. Details are here: https://www.miqrp.net/zoom Zoom ID: 811 0835 6229 The topic for Thursday, 03 April will be TBD. Pete WK8S Ed AB8DF Ernie NE3TE Stan WB8QJZ Tom WW8LA Casey KC9IH Jacob N3JU Stuart M0SGV John K4XNY Pete shared his recent experiences with a POTA PERformer vertical antenna. He went to a local park and took a bunch of pictures. He was doing WSPR testing and showed a report from WSPRNet. His results were good and he is convinced that the elevated radials greatly improve the vertical antenna performance. Ernie mentioned that Buddipole uses one elevated radial and recommends going to the Buddipole web site. K6ARK has videos on different ways to connect the radial wires. Steppir has information on elevated radials on their web site. https://whiteriverradio.com/wp-content/uploads/2023/07/POTA-PERformer-Antenna-by-KJ6ER-2023-03-1-1.pdf Michael KB9VBR WI POTA Videos and J-Pole Antenna Sales https://www.qrz.com/db/KJ6ER KJ6ER - PERformer, Challenger and Dominatorportable video https://www.buddipole.com/antennas.html https://consumer.steppir.com/wp-content/uploads/2018/11/Radial-Systems-for-Elevated-and-Ground-Mounted-Antennas-2.2-12_2018.pdf The agenda for the 03 April QRP Chat: Ernie to do a short introduction and acknowledge any new folks to the Zoom chat. The topic for next week will be on TBD. During the open forum anyone can take the floor. We will go one by one until all have had a chance to have the floor. Files, pictures and presentations can be shared if you have any. Please try to stay muted when someone has the floor. Thanks Ed AB8DF

I was excited to load the beta SSB firmware on my working QMX+ Transceiver. It was originally running version 1-00-27 very well. The SSB firmware loaded apparently fine and booted up. however it appears that something is wrong with the receiver side while the transmitter provides normal CW output. I see some sort of noise pulsing at random in the audio output and see led burst on the S meter. In my process of troubleshooting I tried to return the QMX+ to it’s original configuration by loading the 1-00-27 firmware which loaded but demonstrated the same results As the 1-01-03 firmware. Multiple reload attempts resulted in the same. I am at a loss as what to do next. It seems that something went awry in the initial loading process. Any ideas?

My radio generated an SWR alarm after WSJT-x briefly transmitted on one of the "receive only" bands during band hopping. Whilst this is a very desirable traits, I discovered that it was no longer possible to QSY via CAT. Power off reset cleared the condition. de VK6XT.

Thanks!

I recently finished my first build of the QMX and can't get it to power up properly. At first when I pressed the left encoder, the power consumption went up to 440 mA and then back down when the encoder was released. After some inspection I thought that I had blown Q101 because it was getting hot with the left encoder pressed. I replaced it and my consumption when down to 340 mA but it would still not power on. Thinking it was a problem with the power board I ordered a new 3.3V power board and replaced it. I still get 340 mA when the left encoder is pressed. With a 7.0V supply I am getting the following voltages with the left encoder pressed. +12V: 7.0V LIN_REG_EN: 5.1V VDD: 0.2V IC101 VI: 5.0V IC101 VO: 1.2V IC101 GND: 0.5V Would appreciate some thoughts if anyone has had a similar problem or might know what is going on Thanks, Jeremy Goates KK7QVY

Can anyone confirm the wiring to the PCB is correct in the assembly manual ? Fired up my new QMX for the first time and was somewhat upset that everything was working but no signals were passing to or from the antenna. tracing the signal path back from C445 to the antenna socket I found nothing passing through T507. Sure that it was correctly but removed it temporarily and jumpered across. Rig is working perfectly now but without SWR protection until I rewind the transformer. Looks as if the PCB was reworked in that area because there is nowhere to put the leftover capacitor lead link, Ha Ha .

This probably some configuration with my terminal emulator. When running the mic test I get the bottom row. However, it does not scroll up. So I don't see the history covered on the beta firmware page. I've tried a factory reset. I'm wondering if anyone has this issue and knows how to resolve it.

Good Day, Inquiring as I read somewhere in all my reading on here that some of the original QCX classic kits had different cores and where replaced to include "better" maybe cores later on. I bought and put together a classic for 40m and it was my first HF radio and my first QSO was on it. I also bought one for 30m band at the time as an incentive to upgrade from my technician license. Figured i'd build it when i upgraded. Well, in the mean time i have built some QDX's and a couple QMX's but I still have this 30m classic and bama case to put it in. Just upgraded my license two weeks ago and I'm eyballing that 30m classic to build it now. Question is: It's a rev3a I believe without checking, do I need to get replacement cores or did it ship with good ones? If i remember correctly it was two different parts sources but my recollection is foggy. My 40m radio seems to work fine so I'm thinking it was an earlier issue but figured I'd ask! Thanks! Ryan w0wly