Sunday, July 08, 2007

Buddistick Radials

Thanks to NE1RD for his explanation of what he uses for additional radials with his Buddistick. I borrowed his idea, and constructed 9 "add-on" radials for my Buddistick. (It was supposed to be ten, but while I was constructing the "harness" that the radials connect to one of the wires slipped out of the ring terminal while I was crimping it, so I wound up with nine. Ooops.)

Overall, the process went fairly well. I wanted to use spade terminal quick-disconnects, but I couldn't find any that were the actual correct size for the 26 AWG wire (from The Wireman, part #534) that I used. I wound up using some terminals that were for 16-22 AWG wire, and they seemed to work OK. I had to really crunch down on the crimps to make sure that the wires stay in place, but since there shouldn't be any mechanical stress on the wires, hopefully that won't be an issue. (I also learned why folks spend a few extra dollars and buy a racheting crimper rather than just using a relatively cheap "100% hand power" crimper. I only had to do about 30 crimps, and my hand is still sore 2 days later from applying the pressure.)

What you can see in the two pictures (you can click on the pictures to get a larger view) is that I've got the coax (which in this case is just connected to my Autek VA1RX antenna analyzer) connected (the thicker wire) along with about 5 of the extra radials, plus the regular buddistick radial wire. Until now, I'd done all my testing outside, usually with the antenna mounted anywhere from about 3 feet to around 7 feet above the ground. One of the reasons why I wanted to make these radials in the first place is because Scott mentioned in his blog that he often uses them from a balcony or other location where it can't get near real RF ground. For my upcoming trip, I'm not really sure exactly where the antenna will be set up, so I figured that for a few dollars and a little bit of time, I can make these radials up just in case I need them. (The nice thing about using that particular wire is that it's really, really light. According to their website, it weight less than a pound for 1000' of wire. I don't have anywhere near that much, so it adds very little to my overall equipment weight.)

Anyway, I figured that for testing purposes, instead of testing outside, I'd test inside the house, from our bedroom on the second floor, which is pretty much as far from ground as I can easily get in my house. My original intent was to mount the antenna on the outside of the window and run the radials inside. Unfortunately, my bedroom windows have no way to clamp the antenna outside anywhere near vertically, because of an overhanging roof. If I really had to operate from there, I probably could have come up with some way to mount things, but given that A) This was just a quick test, and B) It was about 95 degrees out, and I really didn't want to leave the window open all that long, I figured I'd just see if I could mount the antenna somewhere in the room.

That seemed like a good idea, but the antenna is pretty close to 8' long (and my ceilings are 8' high) when the whip is extended, so I found up putting the antenna on the floor, as seen in the picture, instead of "mounting" it anywhere. (I actually have the mini-tripod, so I could have used that instead of the clamp, and would have if I was going to leave it set up.) What I found after setting things up and tuning (which I do seem to be getting better at doing; and I highly recommend the use of an analyzer to do so) was that I got excellent SWR (1.2:1 at the target frequency) and it seems that the SWR range was a bit more broadbanded that with just the single Buddistick radial. I am still learning about antennas (aren't we all?) so I'm not sure if that is the expected result, but it did seem to work just fine, and, to paraphrase that famous setting, you can never be too rich, too thin, or have too good an RF ground.

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