Would it make sense to build a 12 V regulated power supply using the LM2940? It's current limited to 1 Amp and has a dropout voltage of only 0.5 volts. My intention is to power it with a LiFePO4 batte

Can someone help me as I seem doomed trying to get one of these amps to work properly. My second kit will give me 36v p-p output with 3.6v p-p input only on 14 MHz with a 12v supply. Current drawn is

I completed building QMX number 390 that I picked up at Dayton. I followed the instructions manual, checked all solder connections, and double checked for solder bridges. I connected a 9 volt power su

Hi all, Once again posting a question not very related to QRPlabs, this is just about general RF circuit design - let me know if I ever cross a line and should find a place to post elsewhere :) I am c

I just received the kit for S/N 331, was inspecting it and am surprised that I may be faced with a problem when snapping the boards apart. I have an extra margin along one side of the board combinatio

I just received #383 and as I was pulling the board out of the antistatic bag, the key fob fell out and L102 on the 3.3V regulator board was broken off its base. The leads were still connected so I su

It's alpha firmware, but is anybody having success with the QMX build yet?

I completed a build of the QMX this afternoon. Before I knew that a firmware load was available I tried connecting power with headphones plugged in and noticed a pop when I applied power and the LCD d

I realize that everyone else is excited about the QMX, but my question is an old newbi requesting help for what should be simple, but, for the life of me, I cannot seem to get a handle on it. My situa

Well, I had a friend pick me up a brand new QMX at Dayton. I waited for the build instructions, and then built the rig (I've built many kits over the years and a couple of QRP Labs kits more recently.

Hey Hans and the gang; I finished up my QMX (serial number 100) on Tuesday evening and added in the ALPHA firmware load the following/yesterday evening. Here's my list of "Mis-Steaks" (including sugge

A new chat has been created: Good evening all My QDX HB has been working well, acceptable output on all bands, although a bit low on 10m. Then without warning the OCP was tripped, and now the receive

Hi, Just purchased this great enclosure for the Z4-KX buck module which is popular with QRP stations & makes a great supply for qrp labs units. USB 3.0 PD and XT-60 connector inputs. Great supplier, C

Built the QMX as soon as I got it home from Dayton. Built both the QCX-mini and QDX digital previously without any problems. The QMX will not power up. Tried troubleshooting it with my limited skills

Can an assembled QCX Mini have the TCXO unit easily retro-fitted? -- William, k6whp -------------------- "Cheer up, things could get worse. So I cheered up and things got worse."

I was wondering if the QDX kit ships sooner than the pre-built ones? It is hard to discern based on the wait list as it does not show what is a kit, and what is a built version. Thoughts?

I have finished my build, although I have not fired it up yet. A few comments: 1. This is by far the tightest build I've ever done. The toroids are really squeezed in there. However all of them did fi

When published I had a color manual prepared for the new qmx. I am seeing posts of errata to the original manual. Is there a source for these changes so I can change the original manual?

The QMX was so unexpected - at least by me. And it has, I think, some strokes of genius in its design. Firstly, Hans made it difficult for himself: the decision to fit it all inside a QCX mini case. F

I have recently packaged up a QLG2 plus a ProRock 2 into an enclosure to give me a GPSDO for the workbench. I also happen to have an uncalibrated 5MHz TEMEX LPRS-01 Rb source so I thought it would be