Here are the details of my old 9 Element, 2 Metre Yagi
Started with a Werner Wulf 5 element Yagi and went from there..
All elements are 12mm Dia Al tube and pass through a 32mm Dia
When mounting elements in this manner the boom tends to electrically shorten
the elements, therefore a compensation factor must be included in the design.
This antenna was optimised at a frequency 1 Meg lower than the operating
frequency (CF=0.007) to compensate for the 32mm boom shorting effect.
Ref=1030mm, Drv=980mm, D1=940mm, D2=903mm, D3-D4-D5-D6 all=895mm, D7=903mm.
The distance each element is from the Reflector, all measurements are centre to centre.
1=410mm, 2=720mm, 3=1025mm, 4=1335mm, 5=1745mm, 6=2345mm, 7=2960mm, 8=3575mm.
A Gamma match was used to
transform the approximate 20 Ohm antenna resistance
to 50 Ohm co-ax, other matching systems such as Delta or Hairpin could be used.
C J Arthur (VK3JEG) 1993