Good evening, I understand the WMX’s voltage sensitivity, and especially the fact that most Lithium batteries have a nominal “12v” of 13.5vdc +/-. The power source I’m looking at runs at 12.8vdc. I’m wondering though: is 12.8v “too much”? Thanks. Scott -- Scott A. Johnson scott.a.johnson@...

Hello everyone, I have been having an issue with my QCX Mini 20m where I am unable to access any of the menu or even change the tune rate. This happens after I start transmitting (calling CQ CQ). The antenna that I am using is resonant to 20m. I have even used an antenna tuner as well. I used this radio without having these issues for a while. I am not sure what I could have done that is causing this problem. Any suggestions on how I can try to fix this issue? Thanks everyone in advance, Lidiette

Here's an example of one factory's process. It's much more complex than I imagined. https://www.youtube.com/watch?v=24ehoo6RX8w

https://www.microcenter.com/product/680474/weller-digital-soldering-station-with-70w-precision-iron?sku=705137&iitt=Rf8_RMhWhyULaeighM_-4._j4FVp4Ix7&utm_source=B1142_DIY&utm_campaign=B1142&utm_medium=email&MccGuid=c045c63e-1290-4139-8528-cf6fc6ea98fd Ed AB8DF

Hello all, When I go portable, I use a 12V Makita drill battery which voltage varies between 12 and 10.5V. It is really convenient, the circuitry protects against shorts, it is in a robust case and it lasts a good while. Nevertheless it doesn't play well with the QMX, for some reason sometimes the tension goes up while in RX. I imagine, there is some unintended interaction between the QMX regulation and the battery while the current draw is low. I can't really "afford" the 0.5V drop of a regulator in emission thus I would like to add in between the two a simple linear regulator that auto switch itself in the circuit as soon as the input tension goes above 12V. Anybody would recommend a circuit that is a good starting point ? Even if I need to make modifications/adjustment, a "scheme design" would help me. 73 de Yannig - F4IUJ

What are y'alls recommendations for on how to increase output to 10W on 80 -10m using outboard amplifier using existing kits? QRP SSB is generally considered 10W so I want to get there with the QMX+. -- Dale Hardin KS4NS Elberta, AL

Hi all QDX batch #2 sales will commence at 1800Z on Friday 17-Dec-2021, at http://shop.qrp-labs.com/qdx QDX batch #2 is 375 kits. Some of these have to be allocated to batch 1 leftovers due to the QRP Labs shop over-selling in last few seconds of the frantic 14 minutes on 11-Oct-2021. There are also several promises to be fulfilled and various other special cases. So the actual number that will be available for general sale will be a bit less than 375. The QRP Labs server has been upgraded to a higher performance machine and so maybe we won't see the same overload issues as last time. Regrettably, I have to announce a price increase from $60 to $65. The original batch 1 QDX kits were manufactured in January 2020, a whole different world ago. Unfortunately many aspects of the manufacturing and logistics have increased in price. Even the main microcontroller chip STM32F401RBT6 procurement cost me in excess of $5 extra now, compared to the price in January 2020 before the global semiconductor shortage crisis hit. Just check Digikey, Mouser, Arrow etc., and you'll begin to understand the difficulty of finding these at all, at any price. And this is just ONE part of the QDX. So I have no choice, but to pass some part of the cost increase on, by increasing the price of the kit; $65 is the best I can do at this time. The price of Aluminium has also seen large increases since batch 1 and this has affected the manufacturing cost of the enclosure too; however at this time I am not increasing the price of the QDX enclosure. I ask for your understanding on this small increase and let's all hope for better days in the not too distant future. QDX batch #2 has a new Revision 2 PCB. In particular, Rev 2 PCBs no longer need the four 47uH SMD inductors to be replaced with through-hole components, nor do they need the 220uF capacitor at the DC input, nor do they need the 25MHz TCXO daughtercard installation. So the assembly is easier to do. The full list of changes for PCB Rev 2 is as follows: The SMD pullup resistors R5, 10, 11, 12 and 14 that pulled up MOSFET gates to +5V were deleted, as they were not necessary. QDX batch 2 boards will be supplied with firmware 1.03 ready installed (which will be made available for download shortly), which drives 5 I/O pins in Push-Pull mode rather than Open-Drain mode, this is required to be compatible with the pull-up resistor removals mentioned above. L1, 5, 7 and 9 (47uH SMD) have been replaced with through-hole axial molded inductors that are installed in the PCB properly, like all other through-hole components, rather than tacked on the bottom as a modification. IC2 (5V regulator) has been replaced by 78M05 which is a very robust regulator and this removes the need for the added 220uF capacitor. Additionally IC1 (AMS1117-3.3), the 3.3V regulator, is now powered at 5V from the 78M05. It is therefore working much less hard with only a 1.7V drop. The 25MHz TCXO, decoupling capacitor, and coupling capacitor are no longer on a separate tiny TCXO daughtercard; they are now SMD components installed directly on the underside of the board by the SMD assembly factory. A P-channel MOSFET is added at the DC input socket as reverse polarity protection. The device used is AO3407. It is rated 4.1A and has a specified typical ON-resistance of 34 milli-ohms. At 1A (say) on a 9V QDX the voltage drop will therefore be 0.034V which is of little consequence. A potential divider circuit added to bias the BPF switch IC3 at mid-rail; this was neglected in the original and does not seem to cause any issues but perhaps in the case of very strong signals, could have a few dB impact on dynamic range. IC7 has been moved a little further from the board edge following some reports that it could conflict with the PCB rail in the aluminium extrusion; this seems to be a manufacturing tolerance thing since I did not see it on my builds here, but it did affect some people. Please let me know any comments or questions. 73 Hans G0UPL http://qrp-labs.com

Hi all, Next monday, December 30 is the last QCX Challenge of 2024. Times are 1300Z, 1900Z and 0300Z (Tuesday). Time to get on the air with your QCX, QDX or QMX rigs! Use any accepted mode where you can exchange a signal report, your name, rig and power. See all info here : https://www.qrp-labs.com/party.html Enter your scores at https://3830scores.com/ Join the discord page in the #qcx-qrp-operation channel to post your QRG or exchange other info, or just have a chat with other QRP Labs friends ... https://discord.com/invite/GdZzmhuU8p 73 es HNY, Luc ON7DQ

Hello all A shipping update... We did run out of a few things, and as usual it all seemed to happen at the same time. We did NOT run out of QDX, QMX and QMX+ but I'm manufacturing 500, 1000 and 1000 more respectively of each, so I should be well ahead of any "running out". I'm also manufacturing more of lots of other kits so won't run out. Holiday season then new year then Chinese New Year always makes things a bit slow around December-February but this time hopefully I'm far enough ahead to avoid any stress. Unfortunately with all this I got no SSB work done last week :-( Things I did run out of: 1. Si5351A Synth kits. I have 500 more on order but it will take 2-3 weeks. Running out of these was a nasty surprise. It also means we can't ship any Ultimate3S or VFO kits until the new 500 Si5351A Synth kits arrive. 2. Sticky feet. I have 22,000 more on order but that will also take maybe 10-14 days to reach me. This means all kit orders that include an enclosure, are pending (QCX+, QCX-mini, QDX, QDax-M, QMX, QMX+, 50W PA). All assembled transceivers in enclosures are also pending; we have around 50 piled in a tower in their shipping boxes, all tested and certified and ready to go, just waiting for the sticky feet. I think I will order some 3M sticky feet locally, they won't look exactly the same but I don't think that will matter. In that case I could get them in 3-4 days. 3. T37-6 toroids... I have more on order and they are already in Istanbul; I should hopefully have them clear customs on Monday or Tuesday then in hand a couple of days after that. Until then the QMX 60-15m orders are pending waiting for more T37-6 toroids. 73 Hans G0UPL http://qrp-labs.com https://buymeacoffee.com/g0upl

My new assembled QMX+ showed up on my doorstep yesterday and I was very excited! Everything checks out fine, but I find that I am disappointed in the reported power output levels: 160m 5.7w, 80m 4.8w, 60m 4.1w, 40m 3.9w, 30m 4.5w, 20m 3.3w, 17m 3.1w, 15m 4.5w, 12m 3.2w, 10m 3.8w, 6m 3.1w. I am most disappointed with 3.3w on 20 meters since that is my goto qrp band. I guess that I was expecting power output numbers on all bands to be closer to 5 watts. Should I be disappointed?

Just going to mess with the RX filtering on the QDX-M for 630M. Does anyone know the measured input impedance there? It has lots of variables if you calculate and I don't want to re-invent the wheel. I have an assortment of MCL RF Transformers and will probably use something like the 8:1 ADT8-1T+ or lesser step-up. Thanks, N0UU

Dears, I wish to all of you Happy Holidays and healthy year 2025! -- 73 - Petr, OK1RP http://ok1rp.blogspot.com QMX Midband #5278 | fw: 1_00_019

Hi, I tried to use QMX as SDR receiver, however it shows up as Audio ALSA or PulseAudio server of which neither I use. Has anyone recorded steps how to set this up with something like GQRC or less buggy than SDR++ software? There are so many issues with SDR++ I don't know where to begin with. Digital interface seems to be showing up in Helvum and Gnome settings so it's probably something with the SDR app itself ? Secondly, it works as audio with ALSA but sounds terrible. Is it because it's not really using IQ which I enabled in software? By the way enabling or disabling that on QMX does not change anything to visible devices in dmesg. Is that expected? Regards