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Hi all SSB firmware was released into beta on 17-Mar-2025 after 9+ months of development. Many thanks to everyone who bravely helped test it and patiently provided their feedback and observations. There are now quite a few YouTube videos, forum reports and other social media mentions about on-air successes with QMX SSB. Now that it has been at least 6 weeks in beta and I believe most of the issues have been resolved, it's time to promote it to an official version. I have called this version 1_02_000 and published it on the QMX page http://qrp-labs.com/qmx where I have also published the updated operating manual, which grew from 111 pages to 134 pages. The main changes are: SSB (obviously!) including CESSB, TX Equalization, Mic AGC, VOX, Pre-distortion and and and... Addition of up to two more USB Virtual COM serial ports (up to three total). All of the hardware tests such as RF and SWR sweep, and Diagnostics, are now available on the LCD too. New CAT commands for LCD contents, S-meter, AGC-meter, Power meter, SWR meter, SSB source Complete list (relative to 1_00_027 the previous official version): SSB modes added (USB and LCB), with CESSB, TX Equalization, Mic AGC, VOX, Phase pre-distortion and more Rationalization of menus, grouped into CW, Digi and SSB submenus (now Keyer and Decoder are submenus of CW) Added up to two more USB Virtual COM serial ports (configurable) LCD versions of AF, RF, Image, LPF, Test ADC I/Q sweeps (miniature graph on LCD) New function PA mod. test to check operation of amplitude modulator Diagnostics screens are now available on the LCD interface too Now remembers previous menu location on ALL menus regardless of nesting level Add way of forcing factory reset, press Menu (left) button during power-up Change TX color in diagnostics screen from red to blue, to avoid confusion since red things are errors Added CAT LC command to retrieve LCD contents Added CAT commands SA (AGC meter), SM (S meter), PC (Power meter), SW (SWR meter) Added CAT command SS (get/set SSB input source) Bug fix: PTT P did not work properly Bug fix: Incorrect PA voltage display on the Diagnostics screen 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl
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Microphone pre-amp
2
Hello, Has anybody tried this microphone preamp : https://www.analog.com/en/products/ssm2167.html Evaluation boards can be found for about 5€ looks good to me but I am no expert ! 73, Yannig - F4IUJ
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Hi, I have released a version 1.2 of the solution. Please refer to the readme front page file at the git repository with details: https://github.com/AC8L/QMX_Plus_Autotuner_Internal_Battery_Speaker/ While I am writing this note - a group buy with 35+ participants is happening for this same version 1.2 - organized by Cal (AD8Q) and Stan (KC7XE). -- 73, Sardar (AC8L, 4K6SA, VA3DUA).
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Dreaded dead transmit from SSB Calibration routine
5
On my mid-band QMX ....I wasn't going to do it. I'd read several horror stories but then, as an "experimental amateur radio station operator" I couldn't help myself. The SSB calibration routine was a disaster. Blew the 2A inline PSU fuse, and took out the BS170s. I replaced the BS170s with new ones on hand and applied enough heat, visually checked for other damage (none found), then sparked it up. Receives fine and all functions appear to work (Mode, Volume, Step, Band etc). However, when I try to transmit on CW into a dummy load, I'm only seeing about 340mW on 40m and progressively less as I go up in frequency... Any ideas as to where to turn to next would be very much appreciated... 73, Robert VE7ZN
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QMX Microphone capsules in EU
6
Hey guys. Any idea where i can buy the electret capsule, working with the QMX - AOM-5024L-HD-F-R? I have found it only in Mouser and Digikey and the minimum shipping price is 20 euro. Any ideas of other compatible mics with -24db sensitivity? Thanks in advance, 73 de LZ3OM
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Hi everyone. With the release of the SSB firmware out of beta, I thought I would make my offer to source K6ARKs wonderful little microphones, which can be found here: https://www.printables.com/model/320559-mini-microphone-for-qmx-trusdx-usdx-kx2-and-kx3, one more time. Adam (K6ARK) made a super fantastic little miniature mic case, and they work with the QMX quite nicely. I print the cases in PLA, and have the following colors available: Black, White, Grey, Navy Blue, Orange, Light Green, Red, Gold, Purple, Sand Stone, Light Blue Stone, Turquoise stone, and Marble Stone (The stone colors look like marble or granite - little flecks of darker color in them - The marble one winds up looking like bleached bone). The kit includes: 3D Printed case in PLA 3.5mm jack Electret Mic Element Microswitch for PTT For each mic, $10 for kit, $15 fully assembled and tested. This price includes shipping in the US. I am happy to make you more than one, some people want one for home and one for the go bag, that's great. You will need to provide your own AUX cable (3.5mm male to male) to go between the mic and the radio. I have had several ask what cord I am using, So I have included this link to one I am using and that I test all my assembled mics with; it seems to work quite well: https://a.co/d/36GDDXf (This is a shortened, non-affiliated link to Amazon.com page for the cable I use) If you are interested, send me a private email, and I will send you payment details. My email address is good on QRZ.
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QMX short during SSB calibration?
8
Hello all, Recently completed a mid band QMX build. First serious electronics kit build and I'm a bit out of my depth for sure. But after correcting a few mistakes during the build I powered on the QMX with a current limiting PSU and ran through hardware test last night on a dummy load. All appeared well, or at least the sweeps matched what the manual describes and what others have posted. CW transmit into the dummy load was no problem and between 4-5W on all bands. This morning I decided to try SSB Calibration. Hooked up to the benchtop PSU and a dummy load and let the QMX run while I did some computer work. About a third of the way through I heard a faint crackle and looked up to see 1.5A draw on the power supply and 7V. QMX was still trying to perform calibration. I shut down the PSU and smelled some hot electrical components. Disassembled and do not see anything obviously wrong. I decided to power it back up and this time connect to the terminal diagnostics. QMX powered up but right after the firmware splash screen it immediately began drawing 1.5A again. I quickly connected to the terminal application and as soon as I did the increased draw went away and the diagnostics screen showed normal readings. The moment I disconnected the terminal app the draw came back. Hot electronics smell persists. This is where I don't know enough to continue to track down the issue and am looking for help. Any advice would be great. Thanks, Mike KR4CNM
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Hello everyone! I think this is my first post in the forums and I wanted it to be a good one. I've been thinking about a good cover for the QMX+ since i pack very compact, but don't want my QMX+ frontpanel to be destroyed. So i came up with the 3D-model below. I'd love if you like the model and come with suggestions. I am open to modify or add versions as needed! https://www.printables.com/model/1300629-qmx-frontcover-stand-and-storage The panels are all dual-sided and can be put on the front or back of the QMX+. Below are some photos:
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Hi, I¡¯ve had my QMX+ for a number of months and had tested the then beta now regular SSB firmware with good results except pretty low output power in SSB. As I had never gotten around to fine tune the LPFs when building it I decided this was the logical next thing. So I fiddled with spreading and compressing turns on the toroids and managed to get all bands to between 4 and 5w output for CW except 160m that was already at 6w. Running 12.0v input and build for 12v Being happy with results I then first tested resetting to factory defaults, and then tested SSB output power. Still max 2-2.5w according to the Bird. I then decided to run the SSB calibration again. Worked fine til perhaps 12m or 10m phase. I then heard some terrible noise from the speaker and saw the QMX crashing with all blocks in the display and turning itself off. I tried powering on again, but won¡¯t start now. Just blank display and current protection on PSU kicks in due to over current. I suspect maybe finals are fried with internal short as result? Jonas 7 maj 2025 kl. 23:12 skrev Stan Dye via groups.io <standye@...>: ? On Wed, May 7, 2025 at 01:38 PM, Wiggle Pig wrote: It¡¯s D503 and D504 These are placeholders for diodes that could be placed across the BS170 outputs, as was commonly done with QDX. Hans included them in the design, but has not encouraged installing the diodes, which he believes are unnecessary for QMX. They may suppress spikes, but they also add additional capacitance to the PA, which may affect it adversely in other ways. There were many posts on this list regarding this topic a year or so ago. Stan KC7XE
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QMX+ LCD blank on new build
3
I finished my QMX+ build last week and it is time to admit this is the first kit in my entire life that doesn't work right away, dating back until about 1980. Since all those other kits worked just fine, I never invested in lots of bench hardware nor are my trouble shooting skills well developed. So, having just finished my piece of humble pie, I am trying to figure why my LCD remains blank. The backlight works. There are no characters or blocks, regardless of the potentiometer setting. I haven't hooked up an antenna or earphones so I don't know about the RF/AF sections. I was able to get my Linux Mint PC to connect via USB-C and using Putty, I put the QMX+ into firmware update mode. It was 1.0.27, now it's 1.02.00 as the firmware update worked fine. The terminal mode confirms that the firmware update went okay. I can browse the terminal mode. All of the front panel controls show "Press", right or left arrows as is appropriate for the control. The only thing is the display never shows anything. It is completely blank. I disassembled the case and removed the front pcb and checked every solder joint on the connectors on both the main and front pcb's. All look good, shiny, no bridges, dry joints, nor whiskers. I'm looking for advice. All I have is a DMM to test with. Lincoln N9IN
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Difficulty with the SSB compressor
4
I am having difficulty getting the compressor to work on my QMX+ on software 1_02_00. There are no performance issues with this build and the SSB calibration runs fine. When I use the config settings shown in the manual pictures the audio sounds good on a nearby receiver using an external mic. This is with the compressor off, the default. If I go back into the terminal and turn on the compressor I get high distortion. It is nearly solid noise and transmits near peak power continuously. It doesn't matter what compression value I use, always the same. Even a value of zero. If I unplug the external mic and plug in just a PTT switch, I get the same noise. The only way to get the noise to go away is to do a factory reset. Again, SSB is all good until I turn on the compressor. I have done factory resets twice now. I would really like to use compressor to add some punch but I haven't been able to figure out what I am doing wrong. -- Regards, Earle KC0KVR
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U3S andLPF Relay Sw board
3
Hi all, This is my first post here so I hope it lands in the right place. A while back I purchased the U3S kit and having constructed it found it to work perfectly on the single band . I have just added the LPF relay board to provide an additional 5 bands. The U3S board has the relay fitted and diode along with the LPF and I have removed the 2 relevant wire links. I must be programming the U3S board incorrectly as the unit only transmits on Band 0, that is it will only show its transmitting on band 0 even though I have set the 5 new bands with band 1 being the highest in frequency. Can anyone shed some light on what I could have missed, Thanks. -- Steve Shuff.
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#clock #QMXplus
21
#clock
#QMXplus
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?
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QMX Failure
5
#qmx
Hello, My QMX had low output power (2W vs original 5W), so I have replaced the BS170. When I switched on, high supply current and a burning smell. I have detected a failure in one of the new BS170 (Chinese supply ... ) . I removed all the BS170, and the two power supply boards, but now I have a short between Vdd and ground (Vcc is OK). I started to desolder the VDD pin of IC501, IC502, IC407 ...... no change .... Before starting to desolder the CPU, have you perhaps an idea ?? Best 73, Nico
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Hamvention Flea Market CMX
4
At Hamvention last week, I found an unbuilt CMX, #345 at a nice discount with case, board is REV 1. No markings to indicate low band, mid band or high band. Is it likely low band? Thanks, Mark W4ZIP
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Michigan QRP weekly Zoom Chat
We had four folks join the MI QRP Zoom Chat on 15 May. Please join us Thursday, May 22 (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 to 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 We had 3 check ins today. Stan, Casey and - they talked mostly about satellites. I listened and did paint touch up in my radio room as I disassembled it. Have Fun and don¡¯t forget to visit U.S. Tower booth if they have one. Pete WK8S Stan WB8QJZ Casey KC9IH Tom WW8AL They talked mostly about satellites. The topic for Thursday, 22 May will be FDIM, Michigan Mighty Mite Revival and Hamvention. The agenda for the 22 May QRP Chat: Ernie to do a short introduction and acknowledge any new folks to the Zoom chat. The topic for next May 22 will be FDIM, Michigan Mighty Mite Revival and Hamvention. 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
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I am just having some fun in the King of Spain contest . AGC is giving me some trouble. apart from vy strong stns overpowering the Rx the AGC is too slow to recover. Can anyone direct me what settings to change to ge a quick AGC ? - Martin DK3UW
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Hello, I'm currently building a QMX kit. I'm unable to get the L511 and L512 toroids flush with the PDB. The surrounding capacitors and diodes prevent the toroids from fitting. I have the toroids mounted just above the crowding components. What impact, if any, is there from mounting my toroids this way? Cordially, Rob, AH6X Boise, ID
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I have not been able to see on the initial first power up any means of loading firmware on my QMX+ radio. I was able to see some evidence of 2 files on E drive which is the USB drive on my computer by shorting AUX2 to ground before power on. The two files in E drive are file 1_00_027.QMX and EEPROM. EEPROM is an empty file.. Have I missed something here or do I have a bigger problem that cannot be solved easily? Any help would be greatly appreciated. Thank you, Ron W6ZQ
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QMX 40-10 Follow up
5
I posted here before about building a 40-10 qmx. I did a little more looking and thinking. Looking at AI6XG's mod: https://www.ai6xg.com/post/a-40-10-meter-qmx#viewer-cl0z424097, it seems to preform well and has motivated me to go out and buy a QMX. However there are some questions that I have that I want to confirm/ask. In the blog, he mentions: "According to simulation, adding 100pF to the already installed C402 56pF should lower the peak frequency to about 11MHz. I found that adding 150pF instead, for a total of 206pF, provides good results" In the conclusions, he says to use a 210pF capacitor in C402. However, such a capacitor does not seem to exist. There are plenty of 200pF and 220pF capacitors on the likes of digikey and mouser, however I can't find a 210pF capacitor. Since he says adding 100pF should work, would a 150pF, 180pF, or 200pF capacitor work in the place of a 210pF one?
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Image Name
Sat 8:39am
Sat 8:39am