The Construction Principles for Duoband-Yagis 2 m/70 cm
An interesting phenomenon is the 3/2-lambda resonance of 2-m-elements on the 70-cm-band. A dipole for 2m has a very interesting azimuth pattern on 70cm. 0 dB = 0,85 dBd |
Now we add the 70-cm-open-sleeve-element to the 2-m-dipole. The currents change and we have the highest current in the parasitic fed open-sleeve element. With the correct distance we get one feedpoint for two bands, on 70 cm with 50 +/- j 0 Ohm. |
Pattern of this construction 0 dB = 4,63 dBd |
We can use this open-sleeve-construction as the radiating system in a Yagi for two bands.