What do I need?
Good quality television reception is generally dependent on two things. Firstly, being within reach of a good signal from a transmitter and secondly having the right outside antenna to receive the signal.
In Dunedin, the main nation channels transmit on VHF (Very High Frequency). However, Channel 9, Prime, Trackside and the non satellite Sky service use UHF (Ultra High Frequency). A VHF Antenna will generally not provide enough signal to get a clear picture of a UHF channel such as Channel 9.
So, how do you tell if you have a UHF antenna? A VHF antenna is much larger in physical size than a UHF antenna, the cross members at the end of a VHF antenna are typically greater than one metre long and can be up to 2.5 metres across and spaced up to 250mm apart as shown in the following picture.
A UHF antenna is of much smaller size. The horizontal elements are only a few hundred millimetres in length and spaced down the length of the antenna at no more than 100mm intervals.
The dual system pictured gives a good indication of comparative size.
It may be that you have a combined VHF/UHF antenna as shown in the photo at left. This consists of a combination of the larger elements of a VHF antenna to the rear and the smaller more closely spaced elements of a UHF antenna to the front.
This combined antenna gives the best of both worlds and will recieve Channel 9 as well as the other free to air channels available in Dunedin. If you only have a VHF antenna, you can easily add a UHF antenna to your receiving the system. The final result would be the dual VHF and UHF system shown in the photo on the left.
Rabbit's ears and other indoor antennas are not generally recommended - they are only useful if you live very close to the television transmitter station. Many different versions of outdoor UHF antennae are available at your local electronics, electrical or hardware stores and can cost as little as $70. When adding a UHF antenna to an existing system, a combiner is necessary to add the VHF and UHF signals togther. This device is called a diplexor or mixer and is available in both indoor and outdoor models. It takes the cables from the VHF and UHF antennae and combines them to one cable for connection to your television or video. It is important to choose quality television-specific cable when installing a UHF antenna as the signal at high frequency is diminished by poor or long cable runs.
There are many different types of UHF antenna. Generally speaking the more elements the antenna has the better it is at receiving the signal. So if you live in a strong signal area a small antenna will suffice, whereas in fringe areas a more powerful antenna will be necessary. An easy way to tell is to look at the type of antennas that are already installed in your neighbourhood. In very fringe areas there are further options such as masthead amplifiers. If you are in this position, it is advisable to contact the available professional installers to compare prices then seek an assessment of your site before proceeding. It may be that your signal is obscured by hills or location and that it will simply not be possible to receive at all.
Antenna positioning and direction is important in most situations. The higher the antenna is placed on a building the stronger the received signal will be. It is important to ensure your antenna is pointing at the transmitter you intend to recive your signal from and that there is a clear signal path. Refer to the map in the transmission section for transmitter locations.