View Single Post
Old Oct 25, 2010, 05:26 PM
IBCrazy is offline
Find More Posts by IBCrazy
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
11,093 Posts
Building the antenna - The driven element and reflector

The resonator (which I will call the bowtie) is made out of a single wire cut exactly twice your full wavelength. Since I am making mine for 910 MHz, my wire is 25.79” long. I am using 14AWG wire for this. 12 and 16 AWG also work well.

The first thing I did was mark the element at every section length for a total of 7 marks. These will be the bending points. Your bends should be sharp and 90 degrees, but being off a small margin won’t hurt. I first bent mine in a “W” shape. Then I bent the remaining points into the “bowtie”.

The reflector should be square cut with sides of your full wavelength measurement. The reflector size is not critical, so do not worry about being off by a small margin on its size. Since mine is made for 910 MHz, my element is 12 – 7/8” square

Now you need to drill a hole in the middle of it to feed your coaxial line through. You want to keep this hole as close to the outer diameter of your coaxial cable as possible.

Now would be a good time to straighten your bowtie. Once done, place your active element with the center of the bowtie over the hole making sure it is square with the plate. Mark the edges of the bowtie and drill holes for your nylon bolts. Place one nut on each nylon bolt as a stopper. The top of the bolt to the bottom of the nut should be your element spacing measurement. For mine at 910MHz this comes out to be 1.61”. Insert the bolts and secure them with a nut on the back side of the plate.
IBCrazy is offline Find More Posts by IBCrazy
RCG Plus Member