W9TH.com – QRP before QRP was cool…

August 31, 2021 Jeff

QRP Antenna Traps

These traps were specifically desiged to use mini-ductor type coils. I had mini-ductor coil stock on hand, so I wanted a design that would be produce a higher Q trap than ones made with torroids. However, the design can easily be used with torroids. There is a mounting hole for use with a nylon screw to hold the torroid in place. Also, there are places to add multiple capacitors in parallel in case you needed a custom capacitance to achieve resonance for a particular band. The trap PCB can easily fit into a small pill bottle for weatherproofing. For temporary

August 26, 2021 Jeff

New Electronics Workbench

We had a spare upstairs bedroom, so I decided to make a workshop / radio room. Step 1, make a new workbench. Its made of 2×4’s and topped with 3/4″ plywood and masonite. The masonite work surface is replaceable by removing the aluminum trim. Also, the masonite can be flipped over for a new work surface. Here is the bench with everything in its place. I aslo added a mini lathe and mill machines to the side bench.

July 16, 2019 Jeff

QRP Guys End Fed Half Wave Antenna – Part 3

I didn’t have time to test the antenna before our cabin trip, so I took some measurements on-site. The antenna was strung between the upper deck of the cabin and a nearby tree. The wire I used was 63 feet long, I intended to cut it to length when the antenna was put up. What actually happened was I passed the end of the wire through a plastic dog bone insulator and wrapped it back on itself about a foot, and called it good. The SWR turned out to be so close to perfect, I didn’t make any adjustments. Here

July 4, 2019 Jeff

QRP Guys End Fed Half Wave Antenna – Part 2

I found some stranded, silver plated #22 wire that has Teflon insulation. It’s not copper-weld, but it’s tough stuff. I attached a 63 foot piece, and wrapped it around the PCB. According to the chart, the wire should be 61’6″, so I will have to trim the antenna for best SWR on site.