LV2 Amateur Television (ATV) Overview
The LV2's ATV system consists of:
- The color video camera
- The Video overlay board
- The ATV amateur band (1.277GHz) transmitter
- The 1.3GHz power amplifier to boost the ATV signal
- The ATV CAN node
- The ATV "distribution" board which glues all the different components together
System log:
| 09/09/2002 | Done! Except for the ATV transmitter, everything is hooked up. The camera and overlay board were tested with a laptop COM port, and I tested all of the swtiches using the 12V/5Vs supply. Seems to work great, with the exception that the camera's 7805 gets hot just like the GPS' suply... we bought a spare 7805-like SPS so perhaps we'll use that... |
| 09/08/2002 | Michael K. finished laying out the board that Nate started. Now it's time to put the system together. That means hacking the camera, so Andrew's working on that. |
| 08/25/2002 | Figured out how we're going to mount all the junk that makes up the ATV system in the avionics module. Suspend the camera below the batteries on the upper plate of the avionics module, and stick the overlay board, CAN node, and distribution board packed in around it. If we're lucky, we'll also be able to throw the ATV gear up there as well. Began layout of the ATV distribution board. |
| 08/26/2002 | Decided that we can use IRF's IPS511S (Rdson = 80mOhm) for the camera (which only uses 220mA) and overlay board, but we should use the IPS5451S (Rdson = 6mOhm) for the ATV transmitter and PA which may draw as much as 2 amps. Datasheets below. Did a Digikey order to get them... also got some "surfboards" to mount the SMT DD packages into a 0.1" protoboard. |
| 08/27/2002 | Worked more on the layout of the distribution. Drew a more accurate schematic which we'll eventually post here. |
ATV Transmitter and Receiver:
From North Country Radio - http://www.northcountryradio.com/
- ATV12-1300 - http://www.northcountryradio.com/atv1300.htm - $143
- DCNV-1300 - http://www.northcountryradio.com/atvc1300.htm - $45
- NCxxxx - http://www.northcountryradio.com/cases.htm - $13.50
- Hardware - http://www.northcountryradio.com/hdwe.htm - $10.85
- RFMT - http://www.northcountryradio.com/rffsm.htm - $61.60
- Antenna - http://www.northcountryradio.com/duckies.htm - $14.00
Total: $322.10
According to Glenn: the 53.219MHz crystal is multiplied by 24 to get 1.277256GHz. The NTSC video is AM modulated on the carrier, and takes up from DC to about 4MHz. The audio is FM modulated and is set at 4.5MHz with a bandwidth of around 10KHz. Altogether, that's about 4.8MHz of junk. Most video filters start at 6MHz out, so we can think of the whole thing as 6MHz of bandwidth. Since it's AM moduled, that's 6MHz on the upper and lower sidebands - since there's no filtering of the lower sideband, that gives us a final signal of 1.277256GHz +/- 6MHz.
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