Page 17 of the 50W HF QCX Power Amplifier kit assembly manual shows T1 wound counter clockwise and page 18 shows clockwise. It fits on the PC board fine when wound clockwise. Most all QRP Labs coil

One other potential gotcha with WSPR is the frequency you transmit on… you must program the U3S for the actual frequency and not get caught out by the “dial frequency” (like I did!). So for 20m

Indeed, a desoldering iron will desolder and leave a clean hole free of solder in no time.

I tested them in circuit but did not trust the results. You motivated me to remove the BS107's and test externally. Sure enough, the last one I tested was bad. Replaced it and am back up to full

I picked up a spool of 0.33mm enameled copper wire from Amazon the other day and it wasn't too expensive.

I have a 12v power supply from an old laptop that is really quiet, thank goodness. Might want to look at those.

Hi Paul, I would go back to basics and focus on getting the bare U3S with 20m filter working. You should see some, if not many, spots from receiving stations with the basic 200mW output and a simple

I was gifted a complete set of kits for the Ultimate 3S, LP filters, relays, etc., and case that was shipped to my gifter in 2017. I see there are various series of boards and low pass filter

Hi Brad, I would suggest that you tell us what test equipment you have. I have found a digital oscilloscope is probably the most important. For component testing, I use a transistor tester. I start

Brad, Are you testing the BS170's in or out of circuit? They're all in parallel (I believe) and just 1 might have opened leading to lower power out. FETs aren't the easiest to test with an Ohmmeter.

It's expensive but a HAKKO FR301 solder removal tool is the best way I have found to remove solder either from a hole or for component removal. It also works great for removing the enamel from wire

I finally built my Hamvention acquired QDX for 9v. (12v initially, changed to 9v). It ran great putting out 4-5 w on all bands. 40-50 successful QSO's. I then decided to try it on 60m and got good

So I've built a U3S with one 20m LPF. Using on WSPR. Was never heard after a month of operation, yet verified it is transmitting from another radio in the shack. Decided to build and install the

I have several wall warts that I bought on Amazon for $10-$20. I searched 5.5mm 12V power supply. They range in value from 2.5A to 10A. Originally I purchased them for use with my Xiegu G90. I now

At RX, the draw seems to be just about 145 mA. At precisely 12.0V supply, here are the per-band TX current measurements, power out into 50 ohms nonreactive, and overall efficiency: 80M 740mA

Receivedmy package of QDX rev 3 by RFD postal on Saturday. Knew it was smallhowever, tiny I didn’t expect. Its about half the size of my X1MPro. Won’t be working on it anytime soon as its 94 plus

Tim I did exactly that with my build, left it as is making sure the turns didn't touch. The unit works fine as is. John KI3J

Good afternoon everyone, Hans, yes I have been transmitting since 01/06/2022, 24/24 h on the frequency of 144.4905 wspr with a Diamond X200 antenna. Unfortunately and I say unfortunately the

Very nice. I only got about half with my QDX but I was using essentially a quarter wave at ground level in an apartment complex. John KI3J

Esa, No. See https://groups.io/g/QRPLabs/message/74260 73 Alan G4ZFQ