I've been playing with some cheap GPS modules bought from eBay...~£5...Although they do work, they take around 20 minutes or so to lock; I've tried different antennas but the performance is the same.

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

Don't have my QMX yet, but wondering what the available power options are for field operation? Since the 12V limit is (as of now) a hard one, that seems to mean a standard 12V SLA or LiFe battery will

I'm building the QMX and have just installed the binocular toroid T507. As for checking the solder joints, between which letters can I expect continuity? Obviously between A-A, B-B, C-C, and D-D, but

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

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

With Windows 11, JTDX and Putty I get the following: - Putty started with COM 5, the screen remains blank, no indication of menu. (I got the menu once only and could do some settings like <Japanese Ba

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

Hi, finally got a chance to test my HighBand QDX on TX today and started very positive, 20m worked perfectly, have built it for 12v but started carefully with 9 volts so as not to destroy anything :-)

Thought I'd ask advice on the QCX+ battery indicator, to wit: (1) I have two QCX+ rigs: a 40m version (firmware v1.09a) and a 20m version (firmware v1.05). (2) The 40m "7 Other" Settings are as follow

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.

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.

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