Omni-Directional - Circularly (Mixed) Polarized Antenna for 144 MHz / VHF / 2 Meters.

Omni-Directional – Circularly (Mixed) Polarized Antenna for 144 MHz / VHF / 2 Meters.

Posted date: August 18, 2015in: AntennaNo Comments

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Introduction and Background

This is an experimental project that may lead to further development in the future, but even as presented below, it does work and may prove very useful.

I have therefore included this page of information so that you may can construct the aerial and develop these ideas further – either just out of interest and for the sake good old traditional Amateur Radio experimentation or for more permanent and practical uses!

The idea was sparked by the fact that I had been toying with the idea of removing the rotator and dual-band horizontal Yagi from my lightweight push-up aluminium mast to reduce mass and visual impact. I certainly did not want to lose access to the horizontally polarized portions of the 2 Metre (144 MHz) or 70cms (432 MHz) bands, so decided upon trying an Omni-Directional, horizontally polarized aerial.

The question was which antenna would I use to replace the rotatable dual-band Yagi?

Due to the weight of the rotator, the lightweight aluminium mast could not safely be pushed up higher than about 6 meters. Therefore, the Yagi on the stub mast was never much higher than 6 or 7 metres above the ground. A lighter weight omnidirectional aerial, without the heavy rotator, would allow the past to be pushed up to, perhaps, 8 or 9 meters. Maybe even to its full 10 meters on a fine day!

My thinking is that this additional height may compensate slightly for the loss of gain from the Yagi. The additional height would also benefit my vertical Coaxial Dipole for 6 Meters (50 MHz) which sits at the top of this mast. A small bonus.

I decided that I would try simple Halo antennas (HAlf wave LOop) and Big Wheel antennas for 2 Meters and 70cms.

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