This is my first attempt to build a 2-meter beam antenna. I decided on a Quad due to it's ease of use, and it can be both Horizontal or Vertical polarized
The plans I used can be found here.
I modified the design so that the boom can rotate from Vertical to Horizontal.
I wanted to use a single feed point, as opposed to running 2 coax feeds and having to make and tune 2 feed points. I also wanted the coax to hook up at the boom and not dangle in the breeze. Makes the feed point connection not have to be so robust. ( I will take a slight performance hit for a stronger design)
To rotate the boom I used a linear actuator that had 4.5" of travel. I later found I only needed 3" of travel. Unfortunately, the linear actuator only had a limit switch for the fully retracted position. The actuator would over extend or over rotate the boom. (My next project)
I used wooden square blocks to mount the spreader arms on which are 3/8" dowel rods. This would allow me to slide the entire element up and down the boom for tuning. Trying to drill precision holes at just the right spot is very difficult. 1/8" brass welding rod was used for the elements brazed at the corners, and epoxied to the spreader arms.
Not having an antenna analyzer (yes would have been easier), I used a field strength meter and a digital amp meter. (SWR goes up, so does the amperage draw)
First just the driven element, I later found I should have made it 1/2" longer at the ends for tuning, short copper wire made up the difference. The driven spreader is PVC pipe so I could run the coax down the center and out the end. As I added the reflector and each of the directors everything had to checked again. I think I spent 10 hours figuring out the best location for them before using pvc cement and epoxy to lock them in place.
Yes I painted it Red, White, and Blue, only colors I had on hand. Then it recieved 8 coats of clear.
Wanting to use the antenna, and I only have FM equipment (so far), I pinned the boom in the Vertical polarization and put it up.
