Tag Archives: antenna

9:1 End Fed Antenna

After probably about a decade of thinking about it, I finally got around to making a 9:1 UNUN to make a “random wire” antenna. I had the PDF from http://earchi.org/proj_homebrew.html for the 6-40M matchbox sitting on various computers for probably a decade.

I built this around a T157-2 with 18 AWG solid wire. The box it is in started out as a headphone to 2M rig interface. I didn’t add any holes or even have to enlarge any of them. I should have gotten a picture before I closed it up, maybe I’ll do that later.

So of course, as soon as I got it closed up, I had to try it out, so I strung it up on the SOTAbeams 10m mast, and plugged it in to the G90. I put about 31′ of wire on it, no counterpoise, but the feedline to the radio is 25′ of RG-174 coax. There was a contest of some kind going on, and plenty of really loud stations, but I managed to get a QSO with N0KTZ doing a POTA activation in Colorado on 20M.

I bounced around a bit and hit the magic TUNE button on the G90 and I was able to get it to find a match on 160M through 10M. I’m thinking this could be really handy for my next POTA activation 🙂

Tuning up the hamsticks

I spent a few hours this evening with my NanoVNA plugged into a DIY hamstick dipole mount on top of my 8-23′ painter poll.

Several years ago I picked up pairs of hamsticks for 40, 20, 17, 15, 12, and 10 meters. The goal at the time was to use them in a dipole configuration, I got the 40M and 20M sticks sort of tuned a while back… but had not done anything with them for a while.

So… I broke out the NanoVNA, set it up for SWR and Smith Chart and tuned up the hamsticks. Screenshots are from the NanoVNA itself, saved to a microSD card.

While a NanoVNA is not REQUIRED ham radio gear, it’s going to be recommended by me for most hams that express even a passing interest in making or tuning antennas.

Something that I was NOT expecting, was the measurements that I ended up with for the “stingers” on my hamsticks.

40M and 10M both came out to 40 inches.

20M and 15M both came out to 38 inches.

17M is 43″, and 12M is 31″.

So now I am tempted to take two sets of stingers and change them, so that I would have them pre-measured for 38, 39, 40, and 41 inches. That would be most useful for the 40M sticks, which have the narrowest bandwidth, because I could move the best resonant frequency around by swapping stingers without having to loosen the itty bitty set screws.

Most people who are not hams are probably NOT going to get much out of the attached screenshots, that’s fine.