Step 1: Harebrained idea
I thought if one director was good, maybe more would be better. So I used the dimensions from the patch antenna to determine an aperture for a conical wave-guide, this so that I could use my fire-extinguisher based cantenna as a wave-guide feed. The patch directions recommend going to a store like a dollar store for a lid. I happened to find some cutting boards that were just big enough and bought one to test in the microwave. Passing that test, I purchased more and decided to use 3/4" pvc tubing as a frame.
This is the page where you can find the latest version of the waveguide calculator, which I used to find the right length for this cone, based on the diameter of my existing cantenna waveguide, and on the 242mm diameter directors. This software indicated a possible gain of 13 Db. If it came close to that is still unknown as I still need to learn how to measure that. This is also where I can learn how to measure my results, if I would just spend more time there!
Seeing as I'm throwing in software links - Delta Cad is what I use to draw my designs. However, I took several years of drafting classes and what little of that I can still remember is not included in the help section that comes with Delta Cad, sorry.
Step 2: Holes
Step 3: More Holes!
Step 4: Trial Fitting
The first time I tried this impressive looking array of directors, I found that I was getting less of a signal than without the directors. So I quickly hacksawed the frame just after the cone and went with that.
Step 5: The Cone
I finally decided to use a sheet of UHMW polyethylene that I had kicking around, and just cover the outside with aluminum foil. I just didn't feel like using the aluminum panel I've been saving for an oil pan project.
First I used some software to determine the length of the cone based on what the exit opening was going to be and the opening of my feed-can. Then I drew that in Deltacad to find what the short and long radius needed to be to lay out a pattern on the plastic sheet.
The can is 83 millimeters in diameter, the exit diameter 242 mm, so that worked out to a layout radius of 4.5" & 13"
Using Deltacad, I figured that the amount of the layout arcs I had drawn, needed to measure 23" point-to-point on the outer radius. The plastic sheet just happened to be 23" wide, so I measured to the exact center of the sheet before drawing my arcs, and just drew them all the way to the edges. Not having any better tool, here I can be seen using a tape measure to make a mark every inch along the 13" radius. The 4" radius was drawn with a compass. Then I connected the marks and used scissors to follow that line. I took a close-up photo of the paper you can see in the background, that's my notes for this project. This will show what I mean about the dimensions of the cone.
Step 6: Needle and Thread
Step 7: Finished
From 50 yards, I'm almost getting a full strength signal. And at the shooting range I'm getting an 18 Mb connection from 300 yards. But the side-lobes are huge! The signal strength meter starts to drop at around 30 degrees to either side of the antenna. Good to find a signal quickly, but I want more focus.
Now that this is what I built, I'm thinking about building a 5-gallon bucket antenna. If I can put the wave-guide inside of the cone, make the cone bigger, who knows?