Here are the dimensions of the 23cm Yagi I built. I had a JPG prepared for an article I was working on, it may not scale 100 percent on screen please download the file and print it.
Some (calculated) figures:
10 el. 3dB bandwidth = 41 degrees, gain = 11.7dBd
21 el. 3dB bandwidth = 27 degrees, gain = 15.4 dBd
The elements are aluminium rod 4.0mm, construction method is elements bonded through the boom (15x15x1.5mm). Element lengths are valid for 15mm boom (correction factor applied).
The folded dipole is (welding) rod 3.2mm, construction is 25mm bend (inner) diameter and mounted fully insulated from the boom. Dipole center gap is 5mm.
For transport I made the boom in two sections, a round tube fits inside for quick alignment and two M6 bolts will temporarily fix the two sections.
This design allows to cut the antenna virtually anywhere past the 10th element, say you had a 1m boom available that would be long enough to make a 15 el. Yagi. It is all part of the experiment.
73, Phil ON4TA
