Our favorite fashion hacker/ham, Diana Eng, KC2UHB, has posted a new article on the Make Magazine blog with instructions on how to build an End-Fed Half Wave antenna tuner and deploy it with an antenna. (BTW, did you see that she was recently named to the ARRL Public Relations Committee? An excellent choice the League.)
Her BOM calls out an air variable cap from MFJ and a T94-2 ‘roid, so I suspect that her tuner could handle a bit more than QRP power. In typical ham fashion, it appears that she was too eager to get it on the air to worry about little things like putting it in an enclosure. FB with that Diana, I think most of us can relate.
It sounds like she had great success using this setup with her FT-817 for some SSB QRP fun:
Setting up my antenna for 20m the first time took about half an hour, and I was able to get very close to 1:1 SWR using the 9:1 input with a vertical wire supported by a tree. Over the next hour or so, operating from a park bench in Brooklyn, using 5 watts on sideband, I made contact with stations in the US, Europe, South America, the Caribbean, and Hawaii. The furthest station was about 5000 miles away, which means I was getting 1000 miles per watt out of this setup. I’m sure it was a big contest station and not another QRP operator sitting on a park bench with a wire antenna, but it was still fun.
I’ll take this opportunity to shamelessly promote my own EFHW tuner, which I’ve managed to get back up on my new website. Don’t forget to compare to AA5TB’s design, which features probably the best page on this subject matter which I’ve seen.