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Is there a way to modify the PTT timing to run slightly ahead of transmit in semi QSK mode? I'm trying to configure the QMX to operate with an SDR switch, but it's pretty consistently tripping the SWR protection (even when transmitting into a dummy load downstream of the switch). I'm thinking that this is happening because the relays have not settled before transmit starts. Greg, N1TR

Hello all, in order to have a good audio volume on WSJT-x (the green slider on the left of the WSJTX screen) I adjusted the audio level per band and some had to be set up to 70 istead of the default 54. So far so good but now I can not turn down the audion for the headphones down to 0. No I don't have the headphones on in DIGI modes :-) , but that applies also to CW and there now the audio is too loud for me on some bands. Could the audion setting be different for Digi and CW or SSB ? I believe the default setting would be fine for any mode except DIGI. -- Martin DK3UW

Hi, I'm looking for amplifier recommendations to boost the signal on my QMX+. It doesn't have to be more than 10W or so. I have considered the QRP Labs 10W amplifier, but I think it needs a band pass filter for each band? I'm not an expert on amplification. The chinese have some offerings for QRP transceivers - I understand one of them is not that good ( the 50W HF Power Amplifier for USDX) but are any of the other ones worth a look? Any recommendations or other tips? THX!

My QMX+ was built by QRP-Labs. It has worked well for about a month, listening and practicing CW. Today I upgraded from 007 to 009 and ran the full configuration routine with a dummy load. The radio felt warm, not hot. It is connected to an OCFD antenna with a SWR a bit below 2.0 on 10 meters. I cancelled Practice Mode, started sending QC while monitoring the SWR (about 1.8 on the display). After about 1 minute, the QMX+ shut down. When I turned it on again, the display grid was all black dots. I removed the cover and adjusted the display pot so it was readable. Turned the radio on and sent CQ a few times. After about 10 seconds the radio shut down again (and again, and again). I performed the factory reset (Twice) and reconfigured the QMX+ for my key and display options (SWR and battery). At this point the radio will power up, the display looks correct and the menus work. CW Practice Mode works, except each character is followed by a loud POOP! Transmitting CW or SSB causes the radio to reset and sometimes it shuts off. Any help is appreciated. Be kind (I've had a difficult day) 73

Can I ask Questions about this here? https://qrp-labs.com/lightaprs2 Or is there a separate group to discuss this tracker? Joe WB9SBD

Hi Hans, first of all: I am very satisfied and happy with my new QMX with SSB beta firmware. Would it be an very big effort to implement 500/600 Hz TX/RX-filter for SSB-Mode in the future? Vara500 for VarAC and Winlink are already working successfully with the new SSB firmware, even with "normal" 2500 Hz filter intended for voice. But it would be smoother for narrow modes like Vara500 or RobustPacket (RPR) to have an more narrow filter. Thank you!

Hello, Has anyone else experiened this quite loud noise with their QMX? It is using the latest software and I am using it with a 12 Vdc 1.5 Amp switch mode power supply. Best regards Richard GW4MTE

Well, I bit the bullet and installed the 003 FW. Update of FW went all fine, no issue there. I wired up a electret mic I found in my junk box. Tested the mic on pc and sounded fine. I made an adapter using the electret mic and a foot switch for ptt. The Mic and ppt switch works. But... Testing SSB TX with QMX on dummy load and listening on my ICOM 7300, the audio is badly distorted before calibration and even worse post calibration. So much so that the speech is unintelligible. The audio sounds like the QMX is only picking up the peak signals from my voice. Most of the calibration plots look nothing like the example ones from the release notes. And only a few mildly resemble the examples. Adjusting mic gain to about 70 seems to improve the audio. However, every time I key up, there is now an awful lot of noise before I even start speaking. Once I start speaking the audio is ok'ish with a load of background noise. I tried messing about with other SSB settings with no improvements. I did find a second electret mic that gave me similar results. I have now set it back to factory default and seeking advice. Any suggestions? Mel. M0KMD.

While you have the BS170s out, consider installing sockets. Cut three pins off of a machine-pin DIP socket with a Dremel tool or a teeny tiny modeling saw. For the 3 and 3A boards, you have to spread the two end pins out a little bit to get them into the holes in the PCB. For 4 and later boards, the pin spacing is perfect. 73 Jim N6OTQ

The clock on my QMXplus seems to drift many minutes every day. When I do an operating session or a POTA activation I will need to remember to set the clock when I sit down and power it up. I set the time to UTC to make paper logging easier. I have a new quality CR2032 battery in my QMXplus in case you wondered. i haven’t yet measured the clock drift, but was surprised it was significant. I think a number of contacts I uploaded to LoTW had no QSL because my estimate of the correct time was wrong. (A day or two later I discovered the time was way off before I uploaded, and changed the times in my electronic log to my estimated corrected time) Or I could get the OLG3 GNSS module which I think will set the QMXplus time, but that requires another component and setup to my portable kit. I probably won’t bother but keep thinking about other solutions. My Home QTH transceivers are spot on the correct UTC time. I can take a PC or IPad and do my logging on it. Another component to take. Q: Before I decide what to do, How much does your QMXplus clock drift?

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_008 to it. Improvement to synchronization section of the SSB calibration - as per this morning's email. On bands where the receiver is found to be overloaded during the sync optimization phase of the SSB calibration, it tests other BPFs to find one that attenuates a bit more to reduce the overload. This has a marked effect on some bands, and it should fix several instances where people reported that calibration wasn't successful on some bands. Bug fix: CAT LC; query now includes commas and dots, requested by Adam. Bug fix: Re-run of PA amplitude modulator test didn't clear the old graph. Added USB Gain to SSB configuration menu (gain for audio coming from the USB port) - specifically as requested by Sergey for use with VAR which does not appear to put out sufficient volume. Now remembers previous menu location on ALL menus regardless of nesting level - Stan and others. Up until now when you went into the top level menu, you went back to the last place you were last time you exited the menu. Now this is extended to cover all levels of menu nesting. Microphone VOX now works on raw external microphone audio, not including correction from onboard mic. (I expect the next thing will be a complaint from someone who actually was using the internal microphone, though it wasn't officially enabled, with VOX - but now they can't because their VOX will be ignored). Bug fix: If running Calibration and I open another terminal window, it will update in the new window. One more minor USB multi-port attempt (directed at Win7) - for Ludwig to try it again and report back... 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl

Hi all, After the calibration with an earlier SSB beta version the maximum power is drastically less in CW mode. In the meantime I have replaced the four PA FETs but without any improvement. What could be the cause of this? I have performed the calibration properly with a dummy load at the antenna output. Maybe the PA driver? Is this easy to replace yourself? I bought it built :-). 73 Gert - PA1GVZ

<panic_attack_on> some days ago I received my prebuilt QMX+ and did not much with it except testing Flrig and WSJTX configurations as well as getting the ssb-firmware onto the precious thing. all went smooth, althoug I did not test any TXing, as I had no suitable antenna. so as today, a legal holiday here, I wanted to head out to a mountain nearby to check some real stuff. That for I installed teh latest firmware (..._009). everything went well. I left it running a bit and headed to lunch (ok, this will have had no impact, thats for sure). one last reboot before I wanted to head outdoors to check: everything ok. before disconnecting powersupply there happened a slight spark between the input pin of the PSU (LiPo 4s) and the case of the QMX+ when I then was on the hill I was not able to power the thing up. pushing the button does nothing. i tripplechecked powersource (slightly below 12v) so my questions are: how big is the chance, that I fried the thing (before even having had one QSO)? and, much more important: is there somebody near OE (or insode EU) who could test and possibly repair the beloved thing for me? thanks in advance Peter

I connected my QMX to a 20 meter QCX 50 watt amp and the result is failed QMX transmit (no power). My QCX does OK with this amp but the QMX took a permanent dive for some reason. Receive is fine, but transmit is now zero. Transmit does draw power from the supply but offers no RF. Supply power to QMX is exactly 12V Supply power to 50W amp is 20V Each has its own regulated power supply Ken AA7JC

Hi Folks, and Seasons Greetings etc. I've been reading up on a 'simple' Raspberry Pi Pico based SDR receiver,with Waterfall display in the Magpi Magazine #148 - 'simple' might be true if component count is the only criteria, To me the software is frightening ! <https://magpi.raspberrypi.com/issues> The RF side of it is a Bus Switch - essentially a very stripped QRP Labs X - with the LO and IQ demod done in the software Pico and driving a small speaker or headpones. The received audio is quite good :-) Thee are a few 'issues', one is with the resolution of the Pico LO as the frequency rises so... I'm wondering if there is any reason not to use a QRP Labs RX and VFO as the 'front-end' and just using the Pico for demod/fitering etc, effectively producing a self contained Multi-mode receiver.with the footprint of a U3 Has anyone tried it? 73 Mike W

Just got a new QMX. Thanks to all for making this happen. Worked perfectly out of the box. Yesterday I was decoding FT-8 and JS8Call on several bands. Nice sensitive receiver. But, I was unable to send since I didn't have a serial port for the CAT commands. I'm running Windows 7 Pro, 32bit, so I got the driver file from STMicroelectronics as noted in the docs. Followed the instructions as best I could, but no joy. Not only did a USB serial port NOT get installed, but the QMX device on the USB port also disappeared. So now dead in the water. Darn it. I can understand the serial port not showing up but the QMX device not being recognized when it was before is a puzzler. Uninstalled the STM software but no change. As I mentioned, Win7 Pro, on an HP Probook laptop with 4 core processor at 2.56GHz and GB of RAM. Anyone have any thoughts on this? I am very experienced with Win7, 35+ years of computer administration experience at HP. I have other laptops to connect the QMX to, but this laptop is the one I was going to use for portable operations. Mark KD0QYN