I made a short video where I attempt to cover antenna theory basics or as I call it "black Magic".
I put my new home brew Yagi antenna up for a few minutes this past week.
Here are some pictures:
Mounted around 17 feet in the air, on the end of a painter's pole. I was hitting the repeater at Ga Tech and Bank of America building 50 miles away with this set up.
Leaned up on the car. The 2M 5 element Yagi is 66 inches long and 40 inches tall. Made out of 1/2 inch CPVC, six metal clothes hangers, and a few other parts. I'm going to add a few braces to support the pipe.
Handheld radio and SWR meter to test antenna. The antenna tested pretty good (1.2 to 1.4 SWR or 3% signal loss). You can see the input connection on the antenna as well.
There is nothing in the box, no balun, no matching network. Just one end of the driven element soldered to the center of the connector and the other end attached to the outer shield by being wrapped around a screw and compressed with a nut. The insulating material on the outside of the clothes hanger wire was scraped off at the connecting ends.
The dimensions along the boom are:
Reflector to Driven Element: 0.433 meters (17 inches)
Reflector to Director One: 0.755 meters (29 3/4 inches)
Reflector to Director Two: 1.185 meters (46 5/8 inches)
Reflector to Director Three: 1.688 meters (66 7/16 inches) of
The lengths of the elements are:
Reflector: 1.048 meters (41 1/4 inches)
Driven Element: 0.978 meters (two halves) (38 1/2 inches)
Director One: 0.940 meters (37 inches)
Director Two: 0.944 meters (37 3/16 inches)
Director Three: 0.884 meters (34 13/16 inches)
I designed the antenna with a free software package called 4NEC2. Simulated properties were 1.0 to 1.2 SWR and gain of 10 db. I didn't get that good, but not bad for a pile of clothes hangers. I definitely need to add reinforcement to keep the antenna as straight as it was on the floor when I laid it out. Still, it's fun on a stick!!! And I learned a good bit researching how to build it!
I recently read "Darwin's Doubt" by Dr. Stephen Meyer. In his book he has a calculation about the probability of building a single protein necessary for life. I'd like to thank Dr. Meyer for the calculation and his wonderful book.
Husband. Father. Follower of Christ. Electrical Engineer. Electronics and woodworking hobbyist.