In my quest to find a suitable monoband antenna for my handkerchief-sized lot, I have considered EFHW and inverted V antennas (in another post in this forum).
But wouldn't it be great if I could erect a dipole antenna that I can rotate?
Here's my idea:
My house is built of wood, with clay roof tiles. The root is a typical pitched roof. Luckily for me, it is very easy to slide the small clay tiles to one side and push up a vertical antenna support, (that exit hole does have to be sealed to a degree to stop rain ingress, but still allow the support mast to be turned by hand).
The mast will be a 1.5 inch blue water pipe, extending about 2-3 meters above the roof line. No guy wire is needed because the length of pipe is supported as it passes through the tile hole and is also supported within my attic. The antenna will be a wire dipole antenna that is taped to two horizontal cross-pieces of 1 inch plastic pipe, each about 3 meters long, and joined to the support mast, with the coaxial feed cable running up the mast pipe.
Each dipole element needs to be about 5 meters long. I know that I can bend the dipole at about 60% of its overall length, without affecting the radiation pattern too badly, and that 60% location will be at about 3 meters. Then I use another length of 3/4 inch plastic pipe that is 2 meters long, secured to the end of the 3 meter pipe and hanging down, thus obtaining my overall 5 meters.
I've tested the mechanical strength of this idea and it all looks fine, because this antenna is mechanically symmetrical and lightweight, and my location is sheltered from strong winds.
The other end of my support mast actually passes through the ceiling of the room below (my shack), and the end rests on the room floor. I can simply rotate the mast and antenna by hand from the comfort of my room!
I can build such an antenna... but I want to know if it would be better mechanically and electrically if the 2 meter end sections were connected as a T piece at the end of the 3 meter length, rather than hanging down 2 meters. ie - the end piece would project up 1 meter and project down 1 meter.
In that T piece design, how would I electronically connect the 2 meters of dipole wire to the end of the 3 meter length of wire? Would I still have to use the same length of wire in order to achieve resonance on 20 meters? Are there any advantages or disadvantages of using a T end section or a end section that only projects downwards? Thanks as always for advice and comments
