VHF 5/8wave vertical antennas

Posted on Jan 10, 2013

At VHF, both the 1/4-wavelength monopole and the 5/8-wavelength monopole antennas are widely used. The VHF 5/8-wavelength (144 Mhz) vertical monopole has long held the reputation of providing about a 3-dB gain advantage over the 1/4-wavelength vertical monopole. The foundation of that reputation rests upon theoretical calculations that show the longer monopole to have the derived gain increase when both monopoles are set over a perfect ground.

VHF 5/8wave vertical antennas
Click here to download the full size of the above Circuit.

A second factor contributing to the reputation of the longer monopole for higher gain is the current distribution along the element. Next Fig shows the distribution for both the long and short monopoles, with the ground plane elements omitted for clarity.

Leave Comment

characters left:

New Circuits



Popular Circuits

Miniature Black and White TV System
Plant Watering guard with 4093
Frequency Divider For Measurements Circuit
Extend Timer Range For The 555
Rain detector electronic circuit project
3 channel audio mixer
Relaxation Oscillator
RC oscillator
Precision bright light control circuit diagram
Single-ended Class A amplifier circuit diagram of 6N1 + 6P3P