More “Cheap Yagi” construction notes: push nuts
As I have mentioned in previous posts, I am a fan of the WA5VJB “Cheap Yagis” as described by W0FMS. One of the construction techniques W0FMS describes is the use of a “push nut” to secure elements to the boom. I bought some push nuts from McMaster last week. Since Mom and Dad were in town over the weekend, I took the opportunity brainstorm with Dad about methods and mechanisms for installing the push nuts. McMaster would have happily sold me a tool for $60, but as usual, I was feeling thrifty.
And, this is what a push nut is. They come in various sizes. These are for 1/8-inch shafts (McMaster part number 94807A024).
Here is a jig with an oversized (3/16-inch hole) for installing push nuts:
With a push nut fitted:
Dad demonstrates operation of the jig (why yes, those are tower sections in the background):
Demonstrating how to do the other side, notice that the installed (top) push nut works as a positive stop:
And, a (nearly) finished 10-element Yagi for 903 MHz:
Wow, they have tools to install push nuts? :O)
I’ve always done it the hard way, and cut my fingers up using them and the side of a crescent wrench.
Anyway, the push nuts I used were not as nice as the ones you used. I’ll have to keep that in mind next time I build another Yagi. I used the hardware store type that is rectangular and larger which isn’t as good. The ones you use would likely be better at higher frequencies. Above about 1296 MHz the capacitance between push nuts on either side starts making a difference.
The key to these antennas are making them as close to WA5VJB’s instructions as possible, or really as you are able. That antenna pictured is probably more neatly built than any of mine were, so it should be a very good performer.
One other “hint” that I’ve learned since is that on brass or copper, one can wrap a resistor lead or buss wire around the element (such as the driven) carefully put it into place and solder the wire to it. This works similarly to the push nuts in practice but is messier and takes longer. It works well on the “U” shaped side of the driven however, and I now do that when I build these. Likely that technique would affect the antenna less on 2304 MHz and above also.
Nice job and it’s good to see that someone is still getting use out of my outdated website! 🙂 73…