If you are interested to build TV transmitter for your electronic project this Advanced TV Transmitter With Sound designed by Tetsuo Kogawa could be good idea for you. TV transmitter consists of of the two sections: video transmitter and audio amplifying. Both of them actually is transmitters. The main one generates video carrier while the smaller one generates the exact 4.5 (5.5 in some countries) MHz FM audio carrier. When it is supplied to the main section, the combination generates the audio carrier that is the total of the video frequency plus 4.5 MHz (this is the same in the US but different in other countries: 3.5 in the UK, 5.0 in Italy, 5.5 in Australia and so on: see the channel plans). The Audio section (1)Coil:
The most difficult point is the coil. You can use any type of coil as long as it fits the inductance. But the size of coil for 4.5 MHz is quite large if you use usual type of coils. Here I will use Ferrite Troidal core that is made by Amidon Associates. Wind 0.2 ECW (enamel-coated wire) around the "FT-50-43" (Amidon) in 24 turns. (2)Transistor:
You can use popular ones such as 2SC2001, 2SC1815, 2SC1907, etc. But you must keep the pins (E, C, B). How to adjust:
Connecting the prove of the frequency counter at "#to the audio-in". Then adjust "Trimer cap. (80PF)" as the frequency counter shows exactly 4.5MHz. Sometimes, you have to add some capacitors (depending 100-1000PF) at the "E(mitter)" position of the transistor in order to adjust the frequency.
"Protel Advanced Schematic v2.04 "
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