LV-0 Amateur TV Transmitter and Antenna
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ATV Transmitter Board
?ATV Board Schematic
So how do we get the video images and data down to the ground? In the same way that your local television stations do. We broadcast it! Using Amateur Radio frequencies ("Ham" bands) we have a circuit board which takes video and sound and transmitts them down to the ground. Purchased from PC Electronics, the transmitter board runs at 426.250MHz and outputs up to 1W. The actual schematic is public domain (as printed in the ARRL Handbook), so feel free to make boards for yourself. We didn't have time or the tools necessary to tune the boards, so from our point of view purchasing was the best option.
Note to the high-g rocketry folks: As you can see from the picture, this board was not made for high g gorces. If you really want to pull g's (say, >15g) we're not sure how well this board is going to work. 7-10g's are no problem, but the air core inductors and the electrolytic caps are just asking for it. Consider making your own (smaller) surface mount board.
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ATV Audio board
?ATV Audio Board Schematic
A seperate board injects the audio signal in on a 4.5MHz sub-carrier into the ATV transmitter.
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Using high tech materials (ok, ok, it's just brass rod from a hobby shop) we built our inverted-V 1/2 wavelength dipole antenna with a sleeve balun to transmit the 426.250MHz ATV signals. Congrats to our own Glenn LeBrasseur for tuning that thing so dang well; as the video attests, we got excellent transmissions and incredibly low dropout from the transmitter/antenna combination.
For more information on all of this junk, feel free to contact us at info@psas.pdx.edu!