005: 144MHz end fed vertical dipole (rod antenna)


I got a used pico-2 transceiver of 2m SSB/CW, but the rubber ducky antenna was insufficient for the actual work. I tried various type of rod antenna for higher gain, and I found the end fed dipole of 1/2 wavelengths works well also on 144MHz. In the experiment, the optimum impedance to get a good return loss was around 1kΩ, it’s far apart from HF and 50MHz result. In the photograph, you can see the L-matching network, the inductance is 0.24μH, trimmer condenser is 10pF, antenna rod length is 95cm. Because trimmer's permissible voltage is 50V, the allowable power is one Watt at most. To compare with the J-antenna, almost the same report was gotten in the local QSO. And the s-meter swung 1 or two scales more in the comparison with usual whip antenna of 1/4 wavelength. (making in 2011)



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