The QRPer Board

Any idea what the thread pitch is on "M10" size antenna parts obtained from Ali Express and similar? None of the literature mentions thread pitch. There appear to be three standard pitches for M10 - 1.0, 1.25, and 1.5 mm per thread. (noted metric pitch is expressed as mm/thread where imper...

I recently built a EFHW UNUN from a K6ARK kit (and I asked about the capacitor I broke in another post). I hooked it to a NanoVNA and a 2.2k carbon film resistor, swept 3 to 30 MHz, expecting to see a flat SWR. Instead, the SWR was about 1.5 at 3 MHz and rose a lot - to over 8 - at the higher freque...

Assembling a K6ARK unun for EFHW, I broke off and lost the surface-mount capacitor. Anyone know its value? 100pf? Several online reports suggest the capacitor is not essential on a EFHW at 20 meters and lower frequency. I will pair this with a SW-3B (40-30-20meter), so am inclined to to finish assem...

Another option - modify your key. If your straight key has a 3.5mm TRS socket as many do, and it's accessible, connect (solder probably) a very short jumper between the ring and sleeve terminals on the socket. I did that with one of my straight keys. Easier to just use a mono (TS) cable, of which I ...