KC8AON's QRP PROJECTS
A CENTER ANTENNA INSULATOR WITH FEEDLINE STRAIN RELIEF

GET THIS INSULATOR AT YOUR LOCAL HOME IMPROVEMENT STORE !



 
PROVIDES STRAIN RELIEF FOR THE FEEDLINE AND COSTS NEXT TO NOTHING
 
Here's a neat little center insulator I have used on doublet antennas in the past. It's nothing more than a nylon T fitting that is made for coupling plastic tubing and rubber hose together with and can be purchased cheaply at home improvement and hardware stores. Attach the antenna wires and feedline as shown in the diagram below and use either electricians tape or heat shrink tubing to secure a 300 ohm feedline to the insulator for a strain relief. You can also use nylon cable ties to secure the feedline with if you like. Drill a hole and put a wire hanger loop in the center if you plan on hanging it as an inverted V, or just use it without the loop and use it as a flat top. To use with coax fed resonant dipoles, seperate about 5" of the center conductor and shield, push it up through the bottom of the T fitting bringing the shield and center conductor out oposite ends of the insulator, attach the dipole wires and solder the connections. Then seal the insulator inside with some hot melt glue or non - acidic silicone sealant for weather proofing. See the bottom picture on details about using it with coax. These are great little lightweight insulators that can be used in the field while camping or backpacking without adding a lot of weight to the load you carry. Oh yeah, I almost forgot ! The fittings I use have a 1/2" outside diameter, but they do make larger ones if you want them. Use lightweight speaker wire for the antenna wire to save more weight, and store the whole thing rolled up in a ziplock bag and tucked away with your other gear. I keep one behind the seat of my truck just in case !
 




 



 
73 !
 

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