|4nec2 - Geo - EF0209||4nec2 - Geo - CQM9C4|
Because yagis exhibit a frequency response similar to that of a Low Pass Filter (LPF), it is most important to ensure that the cut-off frequency is well above the desired upper bandwidth limit! Seen here is a direct comparison using Arie Voors 4nec2 software, looking at YU7EF EF0209 and G4CQM CQM9C4, both of similar boom length. Keeping reactance down and within tighter limits will deliver a more stable outcome and most likely to secure results predicted in software. Low Q is the way to go!
|EF0209 SWR||CQM9C4 SWR|
|EF0209 Impedance||CQM9C4 Impedance|
|TANT - EF0209 - Single Yagi||TANT - CQM9C4 - Single Yagi|
|EF0209 - Average Q-factor = 31.3||CQM9C4 - Average Q-factor = 9.4|