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A GUIDE TO ATV | ![]() |
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1.3GHz ATV Reception Shown above is a typical home built receiver based on a satellite television tuner module. These can give excellent results for the cost of such a design. A more expensive solution involves such designs as those made available from Wood & Douglas (Sadly no longer available) Shown above is the previously mentioned Wood & Douglas down converter the 1250DC50, connections to this module are the aerial input, the supply voltage, the AFC output and the 10k multi-turn tuning pot. These modules are again no longer available new, but may sometimes be found on the second hand market at a price. When you add an IF stage such as the W&D VID-IF board a very sensitive receiver can be formed. The W&D Vid-If consists of a wide band thick film input stage, limiting amplifier, phase lock loop demodulator and video output stage. The polarity of the video output can be selected. There is an A.F.C output available. The way that I have chosen to mount this board allows for very short interconnections within the main receiver enclosure. The main connections required to this board are, the I.F input from the 12DC50 down converter an AFC, 6MHZ sound output and finally a video output BNC. The W&D Vif-If has no internal sound demodulation facilities, so if you want to hear what maybe happening on inter-carrier sound, then you will require an additional module. Luckily these are not at all expensive, Cirkit PLC sell a complete kit which can be assembled in under 1 hour. With the bare module as shown you would either need an additional audio amplifier or apply the de-modulated 6MHz signal back into an Astech or similar TV modulator. This little kit uses a standard "TBA120" Television sound demodulation chip, along with a standard Toko RF coil to provide a very compact module. |
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