September 27th, 2008


Inverted-V Folded Dipole

This is my new outdoor antenna!
Dave KA1NCN, Dave KB3NAI, and I made a folded dipole this afternoon.
We hung it as an inverted-V in one of the trees in KB3NAI's yard to test it.

Orange line - this the rope that holds the pulley aloft.
Pink line - this is another rope, the lanyard in the pulley that hoists up the antenna.
Black dotted lines - this is the antenna, made of ladder line; it is held in place with more rope at either end.
Black solid line - the coax cable that runs to the radio.
Grey rectangle - this is the balun that acts as the go between for the ladder line and the coax.

To get the rope with the pulley high in the tree, we used a bow and arrow and a fishing rod. KA1NCN and I picked those up at the store today. I felt pretty silly with a pink fishing rod and a kid's bow and arrow set. The things we do for ham radio! :)

Dave drilled a small hole in the end of the arrow and we threaded the fishing line through it and knotted it. Then, I fired the arrow high over a tree limb. We then pulled the arrow down, connected thin rope to the fishing line and "reeled it" back over the tree limb. Then, we tied thick rope to the thin rope and hoisted that over the tree limb. We attached the pulley onto that and the pulley was aloft.

Ladder line is composed of two parallel wires surrounded by insulation. To prepare it for the antenna, we measured it and shorted both ends. That consisted of cutting off the ends of the insulation, bending the two wires over each other, and soldering them together. In the middle, one wire from either end goes into the balun and the other two were soldered together and then insulated with electrical tape.

The antenna went up easily and it worked well! We even tried it with my radio. I forgot that I had left it at the lowest power setting and we nearly worked a guy with just a half a Watt. He heard us, but not quite well enough to recognize our call. We had just increased the power to try calling someone else when the batteries gave out. I guess I should have expected that from those batteries.

I am looking forward to putting the antenna to use in the PA QSO Party. I wish I had a yard to use it in at other times, too. Guess that will come in good time.

Many thanks to Dave and Dave for the successful day. It brought back good memories of June weekends before Field Day. Can't wait to do that again!