DIY Home made Dipole Antenna

How do you know when the dipole is set at the right length for the band in use? Measure it of course…. (make the dipole out of 30m Aluminum tape measures). 5m + 5m = Half Wave on 20m. 10m + 10m = Half Wave on 40m. 20m + 20m = Half Wave on 80m…

Four Tube Superheterodyne Radio Kit

Build your very own superheterodyne radio. Simple to follow instructions with schematics and wiring diagrams! You get a manual, all the parts including silk screened printed circuit board, 4 tubes, sockets, tuning capacitor, Aerial, Oscillator and IF coils, 4 inch speaker, resistors, capacitors, wire, nuts and bolts etc. Four Tube Superheterodyne Radio Kit (Limited Edition)…

LED VU Meter with LM3916

This was finished months ago and just now I had time to finish the article. LM3916 is a dedicated IC for VU LED meter. Unlike LM3915 which have 3dB step between voltage levels, the LM3916 have nonlinear steps: -20, -10, -7, -5, -3, -1, 0, +1, +2, +3db, just like old school analog VU meters.…

Digimode PC to TRX galvanic isolated Interface

This interface is galvanic isolation of the transceiver from PC computer. Audio input and output paths are separated by transformers; optocouplers serve to isolate the digital paths, PTT and CW KEY. It was built for Icom IC-718 but can be used for any other radio. Interface support PTT keying over RS232 RTS (pin 7) and…

World’s Cheapest Noise Canceling Headsets

When I’m in the shop I usually like jamming to my music but the tunes don’t sound good over the buzz of saws, routers and vacuums. I do what I can to keep the noise down for my neighbors so turning the volume up to eleven is out of the question. Besides being rude to…