31 December 2020

20m magloop update

Considering the success with a magnetic loop for 20 metres, now I wanted to be able to use a bit more power than 2.5W (at 5W it heated the RG-58 coaxial capacitor, at 10W the tip produced sparks).

I got a thicker coaxial cable that serves both as main loop and coaxial capacitor stub. That's about RG-213 size, with 3 mm solid copper inner conductor: the main loop is stronger, but the stub gets more on the way. Also soldering the whole thing together was not easy, let alone cutting the capacitor to the right length!

The current upgrade is shown in the picture at the right. The loop is slightly longer than Spring 2020 edition, while I have not modified the small coupling loop: this results in SWR of 3:1 at resonance point. Still, reports on the reversebeacon.net are a bit better than with the previous version.

First task for 2021 will be to fix the coupling loop to get a match as close a possible to 1:1. And do have some CQ QSOs!