Television on ISS
Analog vers Digital Compressed Amateur Radio TV
Miles Mann WF1F
Analog FM Video requires 20 MHz
Analog FM can only be Down-Linked on 13 cm and higher bands.
Analog FM can be Up-linked on 23 cm... and higher bands.
Analog FM provides good quality Video and Audio.
Digital Compressed Amateur television DCATV
DCATV Requires 100 kHz - 500 kHz RF band width (128 - 384 KBPS).
DCATV can be Up or Down linked on 70 cm.
DCATV will send a lower quality image at FCIF or QCIF rates of 15 Frames per second.
Ground Station Requirements
Antenna-D: 13 cm.. 20dbic $200
Antenna-U: 23 cm.. 20dbic $200
Amp and Preamp: $500
Rotor System and Tower: $1000
Video Converter: $200
Approx.. Cost: $4200
Doppler RX: 80 kHz
Doppler TX: 45 kHz
Antenna-D: 70 cm 12 dbic $200
Antenna-U: 70 cm, same
Amp and Preamp: optional
Rotor System and Tower: $1000
Video Converter H.323: $1000
Approx.. cost: $4100
Doppler RX: 20 kHz
Doppler TX: 20 kHz
The costs of the two versions are very similar. It is expected the cost of the DCATV converters (H.323 protocol) will drop in price from $500 down to $100 over the next two years. This will make DCATV much less expensive than Analog TV.
Ease of use Analog
To receive Analog TV on 13 cm, will require the user to compensate for a Doppler frequency shift to 80 kHz. In one minute the Doppler error will cause an 8 kHz frequency shift. Only experienced users with computer control will be able to properly compensate for Doppler.
Ease of use DCATV
To receive Analog TV on 70 cm, you will only need to compensate for a Doppler frequency shift to 20 kHz. One frequency change per minute will be required to receive a solid FM Data signal from ISS.
DCATV Satellite System
Assuming a DCATV 70cm Mono simplex operation. The ISS receiver will include a Doppler correction circuit (AFC). This circuit will be able to compensate for signals errors of less than 5 kHz.
Pass band Filters will be attached to antenna port to improve signal purity and reduce receiver interference.
The antenna system should include a Circular polarized 3-6 dbic gain Helix.
Transmitter output: Adjustable from 5 - 40 watts. For optimum performance the output should be at the 40 watt setting.
Controller: A modified industrial grade Lap-Top PC will perform all of the control functions, including Video and Audio Compression and De-compression.
Goal and Objective
Install and easy to use DCATV system on ISS.
Design the system for easy access to experience Amateur Radio Stations.
Video can be either Simplex or Full-Duplex configuration.
Analog FM Satellite video will require too much Satellite band-width.
It will be easier to find a radio frequency for DCATV.
More experienced users will be able to access DCATV.
DCATV is compatible with LAN.
The DCATV project is not for beginners, however Video can be saved on Web pages for easy access to Schools.
ISS will need other Amateur Radio Projects specifically designed for Beginners (2-Meter Mono-Band packet, etc.)
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