Category: QRP Transceivers

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

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uBitx V3 – Part 4

Here is my completed uBitx. It worked perfectly the first time I applied power. Well, except I had the encoder wires backwards so the tuning was backwards, but I don’t count that. The microphone, keyer and external speaker jacks are on the front panel. I plan to make custom knobs (red of course) on the lathe when I get time. There is a custom made heat sink on the back. It connects to a custom made piece of thick aluminum on the inside of the case where the final transistors mount. This view show power and RF connections. You can

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uBitx V3 – Part 3

This is my uBitx ready for wiring. Due to the nature of how the case halves fit together, I decided to keep all components on the top half for easy wiring. This presented some challenges for placement of the headphone, keyer paddle and microphone jacks, but I think it will work. The speaker is from an old TV set. Although not yet added, I plan to have my call sign on the speaker grill in white paint. The last picture is the machining of the custom interior heat sink. I had to make it a specific thickness to match the

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uBitx V3 – Part 2

Here is my uBitx case after paint. Notice the heat sink area on the inside and outside of the case. I purposely left the paint off this area so I could use heat sink compound on both sides. I plan to put internal and external heat sinks on the final transistors. 

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