Building my own G5RV by W4EDN
After attending the club meeting in April, I was ready to build my own G5RV antenna. I had purchased the Ladder line some time ago (WIREMAN) and it hung on a peg in the garage. So this morning I did my research on the choke needed and started there.
I found some great information on the actual G5RV document:
“Under certain conditions, either due to the inherent "unbalanced-to-balanced" effect caused by the direct connection of a coaxial feeder to the base of the (balanced) matching section, or to pick-up of energy radiated by the antenna, a current may flow on the outside of the coaxial outer conductor. This effect may be considerably reduced, or eliminated, by winding the coaxial cable feeder into a coil of 8 to 10 turns about 15 cm (6") in diameter immediately below the point of connection of the coaxial cable to the base of the matching section. the turns may be taped together or secured by nylon cord. However this construction can become the source of problems during thundery weather”
So, I made the choke out of RG8X I had, measured out the 51 ft per side of antenna wire, made a center insulator from a piece of 1/2in PVC pipe. Drilled holes for antenna wires, ladder line and hold up rope.
Where the ladder line meets the choke I used an old pill bottle with a slot cut in the side and hole in the bottom. Ran the RG-8X thru the hole and out the top. Stripped off the insulation a bit wider than the ladder line and soldered the ladder line to the shield and center conductor of the coax. Fed the ladder line thru the slot, and pulled it back into the bottle, then sealed it all up with HOT GLUE including the cap.
At the other end of the choke I used a PL259 so a barrel connector was needed to attach my RG8X feed line to tuner in camper.
Figure 1G5RV Coax Choke
Figure 2 Pill Bottle Watertight connection
Tested it using my ICOM 7000 and ICOM Autotuner AT180.
SWR was below 1.3 :1 on 80, 40, 30, 17 meters. At several places on each band.
I’m going to use it for next months NAQCC QRP Sprint. .