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|@ DIR: /ATV|
@ FILE: ANTDESIGN
Below are some simple antenna designs I have made and used with good results. They are all decades old but still usable. Antenna are one of those fundamental tools that only improve with better material technology, the underlying design remains the same, reflector, radiator and directors all on a boom and all made to a specific frequency / band. All antenna will weather and it is just how well the object is made and from what materials that will limit it's expected usable life.
To transmit and receive amateur television signals you need a good antenna. As ATV operates on several bands you need to know which antenna is the best to build for each band. For most amateurs this will be the 23cm band (1241-1392Mhz) or 70cm (425-450).
In Melbourne you'll need a 23cm band yagi or 3cm yagi / dish to transmit up to the repeater. 70cm is used for the repeater's output and a domestic UHF TV antenna usually has enough gain to receive a reasonably good quality picture and a mast head RF amplifier with ~10dB+ gain to really pull the signal out of any noise. You can not use a domestic TV antenna to transmit on as they are designed for a very broad frequency bandwidth which makes it very unsuitable for transmitting on.
70cm Band (440Mhz)
8+ element yagi design (1970-80's)
PDF format: 70cm ant.pdf (12KB)
23cm Band (1.2Ghz)
8+ element yagi design (1990's)
PDF format: 23cm ant.pdf (18KB)
13cm Band (2.4Ghz)
Potatoe Chip Pack design (2000's)
JPG format: 13cm ant.jpg (220KB)
Original diagram from our friends at www.oatleyelectronics.com
73's for now