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I have a QMX (80-20) for 12 V that I built last year. It worked fine on FD, and was used occasionally since. A few weeks ago I was running it into a dummy load. Controlled by fldigi. Power was a LiFePO through a regulator at 12 V with a 1.5 A current limit. After messing around with the fldigi settings until I got it to "transmit" into the dummy load. Output power and input current looked good. Then I got distracted doing something else. After some time I looked at the regulator and it was showing 6.1 V at 1.5 A out. The radio is on, and the display works, but obviously something is seriously wrong. WSJT-X communicates with it. I can change frequencies and modes. I looked at the back of the main board with my IR camera. The hot spots appear to be associated with Q507 and Q504. So I've blown it up, but I don't know what I did. Is there a troubleshooting guide? I've opened it up and there's nothing visually apparent. In talking this out I've sort of convinced myself that I have a shorted Q504, drawing too much current and heating up Q507. Does anyone have any better ideas? Is there any way to test this hypothesis other than cutting Q504 out of the circuit and seeing if the excess power draw goes away?

I just got back from the Pacific NW robotics district championships where N7BIN and team were competing. There are a couple parks just off the highway near Spokane so took time for POTA on the way to/from. I noticed a couple strange things with the 1_01_003 firmware on my QMX rev 2. At one point, after powering down to swap cables, the display showed USB mode but the rig was clearly in LSB mode. I switched to LSB on 20m and everything sounded normal again. It appears that there is some way for the displayed mode and actual mode to get out of sync. When in SSB mode, I noticed that the SWR meter was swinging wildly into territory where SWR protection should have tripped, but SWR protection did not trip. When in CW mode, it behaved as expected. This was transmitting through a ZM-2 tuner adjusted for 1:1 SWR. Despite this, and the challenge of 5W SSB with a low antenna, the activations were still a lot of fun. 73, Mike KK7ER

The wiki page QMX External Microphone Options has been created by Andreas DM7AK <mail2dm7ak@...>.

Just to satisfy my curiosity : which TCXO chip comes with the QCX+ TCXO option? 73 - Pierre - FK8IH

Hello OGs, YLs, Question, actually it could be a feature request.. The stm32 chip has an internal real time clock. Wouldn't it be nice to make usable? Currently the clock may be shown on the display ant it starts counting - starting from zero on power-on. Two things would be needed: - software - a settigs menu where the user would be able to set current time without a need of playing with gps - hardware... the diagram shows that cpu's vbat leg is connected right to the gnd... adding small battery there would be required to persist the time on power off. And since stm32's rtc draws some microAmps, some small button battery should suffice. What do you think?

Just retried a change of tcxo frequency down by 6 Hz. As before it did not work...audio connectivity was lost and had to do a master reset to get it back. Very annoying as have to customise my rig over again. Yes running the 003 SSB firmware. There were other weird symptoms but won't "muddy the water" describing those. de Vk6xt

Fat fingers did it again… Accidently turned on the Two Tone Input. Changing to Ext Mic fixed my problem! Sorry for wasting a little bandwidth…. See you QMX SSB! Mike

Hi All, Upon PPT on the mic sends out a high pitch tone(squealing like a pig in the midwest!)…I am getting good SSB voice transmissions on both my high and low band QMXs’. So pretty sure the mic and cable are not the problem. Any others seen this on their QMX+?? Any ideas for where to look? SSB configurations are the same in all 3 radios.. thanks Mike. n0mpm

https://varac-hamradio.com/so/08PO64Srp 73 DE muhsin TA1MHS

2 fairly simple question, not seen anything oblivious in the digest emails, so apologies if these have already been addressed @hans 1:- now we have the SSB firmware released, can we now do multitone digital modes? or does SSB only work on the mic input and not the USB sound card? 2:- if question one is yes multitone is now possible, will the SSB functionality be a possible enhancement to the QDX as well so it could also do multitone digital modes? thx Peter M0PWX

I replaced the bad output transistor in my QMX, and it wouldn't boot up. I get a USB drive, so I can talk to it through my computer. I tried dropping v27 firmware on it. It hangs on "Initializing: Radio Load" for a long time, then goes to "Band Version QMX 80-20m", which is right. If I leave it it goes to 00,000,032 hh:mm:ss < 32 Where hh:mm:ss appears to be the time it's been up. I've waited on that screen for a long time and it doesn't go anywhere. I can't turn it off from the power switch. So I cut the power. When I turn it back on it starts drawing power, but the display never comes on.

We had seven folks join the MI QRP Zoom Chat on 03 April. Please join us Thursday April 10 (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, 10 April will be an open forum. Ed AB8DF Ernie NE3TE Tony W8CDC Stan WB8QJZ Stuart M0SGV John K4XNY Jean in France John is near Atlanta. He has a 50 foot end feed in the backyard, 20 meter dipole and a 17 foot Chameleon antenna vertical. He uses a Wolf River coil for 40 meters with the 17 foot vertical. https://chameleonantenna.com/collections/vertical-antennas/products/stainless-steal-whip Ernie just got a NANOVNA and wants to test a choke he built. But Taxes!!! are limiting his haming. Stuart got his Michigan Mighty Mite to work and will add some LPF from QRP Labs before getting on the air with it. He just got a TinySA but has not played with it yet. Stan is doing some Slow scan TV using satellites. ISS is one of the birds he’s is playing with. We all want to hear about the results next week. Tony survived all of the bad weather. Got a Michigan Mighty Mite board from the QRP Guys and is going though his junk box to see what parts he may need to order. Ernie is still looking at that the PERformer Antenna and how to add weight to stabilize the tripod. Here are articles that has some info on elevated radials: https://rudys.typepad.com/files/qst-march-2010-ground-systems.pdf https://drive.google.com/file/d/1LwSbXXeovjJdT8ijpOi-9FYR--nNsxgD/view Jean in France could not get the audio to work. We all hope he can join us next time. We talked about the new Yaesu QRP radio and the rumors about it. One rumor was that it has the same receiver front end as the FTDX10 receiver and will have similar capability which ranks highest on the Sherwood list. The agenda for the 10 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 an open forum. 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 just completed loading the new firmware using Putty on my Win11 laptop, I also did the calibration. I took my time and made sure the QMX didn't get too warm, all seems like a success. I have tried BPSK31 and FSQ, it is working well and now to try WSJTX. I have not tried SSB voice as I don't have a suitable mic yet. Randy VE3JO

I have programmed my first message into the qmx+, but when I play it back on the air, it appends lots of extra characters at the end. The characters do not appear in the message memory when you view or edit it.

A new chat has been created: Hello Hans, hello guys, I designed my QRX+ for a supply voltage of 9V by appropriately designing the output transformers. I have now also tested the current beta firmware 1_01_003. I assume that the choice of operating voltage is irrelevant for the firmware. Of course, the required calibration was also performed before the tests. Optimal parameters were found in all individual calibration runs. During testing, however, I noticed that the PD parameters on my QRX+ behave differently. The effect of the software switch for phase pre-distortion is reversed, i.e., the ID3 spacing improves when phase pre-distortion = OFF. The CESSB and amplitude pre-distortion parameters have no effect. I also noticed that with a drive level of 900, in addition to the highest output power, the best ID3 spacing is also achieved. Reducing the drive level steadily worsens both parameters. A dependency of the curves as shown in the diagram could not be observed. Any speculation as to why the firmware on my QMX+ exhibits this behavior? vy 73 Juergen dl9jgo By: Goeckeritz Juergen <groups@...> View/Join This Chat Do not reply to this message to post to the chat. You can participate in chats only through the group's website.

Kudos to Hans - the beta was well worth the wait! Thanks again to the folks that helped me earlier this year locate and replace the bad switch. I had not used the little beast that much after confirming the repair, mostly due to time commitments. Did get some good reports on CW, then shelved it until firmware beta 1-01-003 that covered SSB was dropped. The firmware upgrade was straight forward. I constructed two Mic adapters, one for a spare ICOM HM-219 and one for a Heil ProSet Elite iC. Both worked well without adjustments of any kind. First voice QSO was this afternoon on 40M with VA3XV up in Ontario (about 400+ miles). He reported the audio to be as very nice, as good as my 7610. The QMX+ even received a 54 sig report when the QSB and adjacent frequency QRM was not present. Next up configuring it for fldigi - FSQ and other digital modes... and of course portable ops. So far this has proved an excellent and surprisingly full featured little rig. -- Jack Spitznagel KD4IZ FM19oo Parkton, MD