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

Well, my QDX may not be on *ALL* bands but give me time ! 72, Bill, N4QA

Hey all, What do people usually use as a solar power source for the U4B? I am looking for something cheap and on the budget, so I was looking for a solar power cell on Amazon, but no such luck exists.

Pardon me for being slow, but I want to make certain that I wind this correctly. T507: Leads B and C on the left side of the photo are made from the same wire one loop through . . . . and B and C on t

For Sale: QCX+ 40 / Original QCX 30 / Original QCX 20 Good day, All of the above are excess to my needs; it’s time to thin the herd. All built by me and all in good working and cosmetic order. Origina

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

My recently completed QDX Rev 5 does not seem to be putting out any RF. It is able to receive strong signals on 20 and 40 meters. Control functions and LED seem to be correct. An adjacent XCVR picks u

Hello all After many week evenings I finished my first QCX. A QCX+ Unit powers up, transmits at 4 watts and receives. I have even made successful QSOs. However, something went amiss during the alignme

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

Thanks everyone! I tried Andy's suggestion of putting a capacitor across the DC input, that didn't fix anything. But... I wired the circuit for a 9 volt source, and am using a 12 volt LiFePO4 battery

I built a QMX for 12v and intend to run it on 10v and the output power is great. On 12v power out is >5w on other bands and about 4w on 20m On 10v power out is just less than 4w out on other bands and

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

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

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.

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