I purchased a used TS-480 SAT recently, and I noticed that the insulation on one of the antenna coax pigtails had been scraped away about 2 inches from the back of the radio, leaving the braid exposed and damaged. I decided I would cut off the damaged coax and reinstall the newly shortened pigtail into the strain relief that secured it to the back of the radio.
For those who aren't familiar, the coax goes through a 1/4" hole in the middle of a 3/4" x 3/8" metal plate that is attached to the back of the radio with two screws. Inside the radio the coax continues through a metal tube about 1/2" long, and the tube is hex crimped around the coax to secure it. The coax continues about 1/2" past the end of the tube, where the braid is separated from the center conductor and each is soldered to the respective pad on the nearby circuit board.
I unsoldered the coax cable from the circuit board and removed the coax and strain relief assembly. With minimal effort, I was able to pull the coax out of the strain relief. Where the braid splits off from the center conductor there is a small brass ferrule that goes over the center conductor and under the braid, and the tapered tip of it is pressed into the coax underneath the outer insulation, thereby stabilizing it. With the coax removed from the strain relief, I thought I could merely stretch the crimped tube back out, cut off the bad section of the coax, reinsert it into the tube, add the ferrule, and re-crimp. Unfortunately, the tube split at the crimps when I tried this.
Here's what I did that was quick and easy to do, and looks professional, if I do say so myself!
I cut off the remainder of the tube on the strain relief and enlarged the hole in the flat plate to 9/32". I cut a 1/2" length of 9/32" brass tubing, deburred both ends, and inserted into the hole in the plate so it was flush with the underside. I applied flux to the tube and the plate, and soldered the tube to the plate on the inside surface only, so the solder is facing the radio backplate when the strain relief is reinstalled. The clearance hole in the backplate of the radio is large enough to accommodate a reasonably sized solder bead on the strain relief.
I pushed the coax through the rebuilt strain relief and then stripped back the outer insulation about 1/2". Next, I inserted the ferrule over the center conductor and under the braid, pushing the tapered tip so it was underneath the outer insulation. I pulled the coax back into the strain relief tube so that the end of the ferrule was flush with the end of the tube, then hex crimped it to secure it. After that, it was a simple matter to twist the braid and strip about 1/4" of the center conductor insulation, tin the ends, reinstall the strain relief, and solder the coax ends to the circuit board.
It looks and works like new, and if I ever have to do it again, it will be a very simple matter to take everything apart, solder in a new brass tube, and make a whole new pigtail assembly.
I apologize for the lack of photos, but I didn't realize until after I was done how potentially useful this tip might be for others. I hope my written explanation is clear enough to follow. If anyone has any questions, please reach out.
73,
Stan N6BYU
