TV Antenna Polarity

By Sally Garden

The specification needed to get good TV reception everywhere is impossible to achieve. The very best a caravanner can expect is good reception 90 per cent of the time, as 100 per cent cannot be attained using a terrestrial caravan antenna system or a satellite system.

However, you will get more out of an antenna system if you can adjust the polarity of your antenna. Horizontal and vertical signals are used everywhere, and sometimes both signals types are used in the same location.

So, unless your antenna can be adjusted for VHF and UHF separately, then the available signal will not be picked up. This can be achieved by antennas such as the Explorer C2: it is able to have independent adjustment for both VHF and UHF.

Antenna systems are purchased for secondary or fringe signals, so when signals are strong just about any sort of antenna will work. However a caravanner on the move will need a system that works on low level signals.

Low level signals are sent out both in a horizontal and vertical pattern, and polarity is used to allow greater use of the radio frequency (RF) spectrum.

An example of this would be in Bendigo, Vic. This area transmits two vertical signals on the VHF and three UHF signals on the horizontal plane. An extract from The Caravanner’s Guide to TV Transmitting Sites Around Australia explains that VHF stands for Very High Frequency.

The channel numbers that fit are 0 through to 12 – but do not confuse the number with the program or network, because a network can be viewed on any channel.

For example, in Melbourne the ABC is on the VHF channel 2 and is horizontal, in Canberra ABC is on the VHF channel 9 and is vertically polarised, and in Dubbo ABC is the UHF 57 and is horizontal.

It can be said that horizontal signals are definitely easier to work with. The antennas are generally more effective on horizontal signals than vertical signals, so everyone benefits from putting the antenna where the signal is.

But some antennae can use the signal better than others – in other words they process the available signal without wasting any of it. Signal can always be improved by experimenting with the best position, whether it is height adjustment or location change, eg, back of the caravan rather than the front.

When you arrive at a new location you must direct your antenna using the right polarity and then retune your TV set.

If you purchase an Explorer RV antenna system, they come complete with a guide book to assist the alignment of your antenna system. This book is available to anyone wanting to get an idea of where transmitters are – all 3750 of them.

A quick study of this book shows you that all States have a significant number of vertical transmitters. Once you get your polarity right, sit back and enjoy the improved picture that you get.

For more information on TV polarity contact Explorer RV Reception Systems, 1800 652 705, www.explorer-rv.com.au