Joining RG-8X to 14 ga solid wire
I am in the process of assembling a W5GI "Mystery Antenna" which requires transitioning from wire to coax back to wire on each leg of a dipole-like annenna. What are my options as to making a mechanically secure joint at these junctures? I will solder them for electrical continuity, of course, but am really more concerned with structural integrity as this antenna will only be supported at the ends. My use of solid 14 ga wire, stripped from ROMEX, poses challenges when connected to RG-8X, but maybe opportunities too. I'm considering wrapping/crimping the 14 ga to the external sheath of the RG-8X, then wrapping and soldering the braided interior wire of the coax to the 14 ga, then covering the whole thing with shrinkwrap. Comments / concerns / advice?? Thanks, Mac.
Double bazooka antennas face this same challenge.
I usually do this:
Strip the end of the coax for 2" or so, exposing both the center conductor and outer conductor (braid). Twist the braid around the center conductor tightly. Then overlap that 2" area (where the coax conductors are connected and exposed) with the 14 gauge solid wire. Then I use #20 or #18 (something thinner and a lot more flexible than 14 AWG) to "wrap" several turns of this thinner wire around the coax conductors and the heavy 14 gauge conductor, wrapping the turns very tightly to form a strong mechanical bond. Flow solder over all of that, completely covering all the conductors.
Heatshrink over that, overlapping the splice joint by an inch or two. Then I wrap self-vulcanizing rubber tape tightly over the entire splice area and the heat shrink, followed by good vinyl electrical tape like Scotch #88, overlapping wraps.
It's pretty strong. If anything breaks, it doesn't break at this splice.
Unfortunately RG-8X isn't all that strong, and it sometimes does break, but not at the splice.
One way to prevent breakage is to use a messenger rope for the antenna elements. Pull that very taut and tie it off securely, then hang the coax/wire antenna from the messenger rope. That way, there's almost no mechanical stress on the antenna, it's all on the rope.
Yeah, thats pretty much it. I would go ahead and solder to the coax shield and the center conductor.
I have also used wire/zip/cable ties when making a coax-coax connection for a bazooka antenna.
The best way would be to make your electrical connections, then use a piece of rigid plastic as a backing and wire ties or a stiff piece of solid wire to tie it in place.