I wanted a simple antenna that I could hook up to my handheld VHF/UHF transceiver for better performance. This solution has that mission in mind; the yardstick is held in one hand, orienting the antenna for vertical or horizontal polarization well away from the operator's body, vastly increasing the range over the heavily loaded rubber duck that comes preinstalled on most inexpensive (Baofeng) rigs, which is held in the other hand. 10 gauge (2.5mm diameter) solid copper wire serves for the elements, hopefully making the antenna narrowbanded enough to help avoid desensitizing the receiver with strong out-of-band signals. I also wanted a way to connect the coax to the dipole elements without need of soldering equipment. #10 x .75" machine screws are threaded in from the rear, which bite into the wire elements, simultaneously making good electrical contact while forcing the inside end of the wire against the yardstick, anchoring the insulator in place. Once the shaft of the screw is flush with the end of the round hole, a nut is laid into the relief, and the screw is threaded through the nut until it is snug, leaving plenty of excess to be used as a binding post. The coax is stripped back enough for excess braid and center to be wrapped around the binding posts (#10 crimped terminal rings would also serve nicely) and wingnuts are used to secure the connection. The coax is positioned in a graduated relief, and a zip-tie (with the buckle positioned on the rear) is pulled tightly to secure it, providing strain relief to the connections.
This insulator might also serve well for HF antennas. A piece of yardstick could be used to provide an eyelet for catenary suspension rope.
It is worth noting that steel (screws) and copper (antenna elements) are dissimilar metals. Long term installation should include some kind of dielectic grease to slow galvanic corrosion.
If the construction/implementation of this insulator is unclear, message me here and I will clarify.
PRINTING: Suggest PETG for long-term outdoor installation. PLA is fine for other short-term applications. The STL should load in the correct orientation; the long, skinny, flat edge with the coax relief ramp goes on the print bed, with the terminal post holes and hex nut reliefs facing the Y axis. Infill of 15% is plenty.
Antenna construction: You will need 2 equal lengths of 10 gauge (2.5mm diameter) solid copper wire cut for your frequency of interest, two #10 x .75” machine screws, four nuts (two of them can be wingnuts,) a cheap yardstick (5/32” thick, 1&1/8” wide,) and approximately 5 feet of coax, RG8X or similar. (RG174 will suffice but securing with zip tie on the end may require wrapping with electrical tape to add girth.)
1.) Slide the insulator over the end of the yardstick.
2.) Insert wire elements. Thread screws from the rear. They should bite into the plastic and turn by hand until they encounter the wire. Using a screwdriver, rotate (should not need to push!) the screw. The threads will bite into the wire, causing a worm-gear effect that will push the end of the wire up against the yardstick. Once the screw is level with the round hole, insert a nut into the recess and continue turning the screw. Some finesse may be necessary to prevent cross-threading the nut. The screw does not need to be ridiculously tight. Stop tightening when the screw head is bottomed out on the plastic.
2a.) Your wire will likely come coiled, or not straight at all. Before cutting your elements, take a full length piece a couple inches longer than you need, and clamp one end in a bench vise. Clamp a pair of locking pliers on the other end. Pull the wire as taught as you can muster, and give the pliers a couple of sharp raps with a hammer in the direction you’re pulling. This will put a very straight set into the wire.
3.) Strip the outer jacket of the coax approximately 2.5”. Tease out the braid with a pin or similar tool, and twist it into a wire-shaped bundle. Strip approximately half an inch of the dielectric from the center conductor. Make certain there is no stray piece of shield contacting the center conductor. Wrap the shield/braid wire around one binding post, the center conductor around the other, and secure with the two remaining nuts.
4.) Position the coax so there is some slack between the jacket and binding posts, and use a zip tie through the slots to keep the coax from being yanked off the connections. Tape can be used to secure the coax along the yardstick to the other end.
5.) I just realize I need to add something to the wire ends to keep from poking someone’s eye out..."Eyeprotector.stl" is for gluing onto the ends of the dipole elements to keep something unfortunate from happening while you're rushing outside to work that rare DX.