HFU HF Underground
General Category => General Radio Discussion => Topic started by: RadRoadrunner on October 04, 2016, 0252 UTC
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I was doing some research on SSTV and thought the transfer rate was slightly too slow for an idea I had. I was wondering if it is possible to transmit modified Television over shortwave pirate bands. I realize 6 Mhz would be extremely too wide for shortwave, but I thought there might be a way to transmit a highly compressed form of image transfer over about 20 Khz with no audio and have it perform at a framerate of 15-30FPS. Any thoughts?
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Not enough bandwidth for that kind of frame rate, sorry.
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there is actually.
the same method used to connect to the internet through telephone land lines (dial up modem) from the 1990's.
you can send compressed video with sound, 320x240 @ 15 FPS using H.264.
there are problems though.
it will not work with signal propagation (fading).
you need a full duplex transceiver for TCP packets (simplex for UDP packets)
the signal must be strong and clear of interference.
its too costly and inefficient.
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Why not a slide show in Slow Scan?
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Why not a slide show in Slow Scan?
not sure how well that would work out given the few minutes it takes for each picture to scan completely.
you could probably cut that time in half by reducing the vertical and horizontal size of the picture to half its size being scanned (the output size).
either way, it will still take significant time to send a slide show.
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There is such a thing as NBTV, narrow band television. most of the displays are mechanical with 32 lines in a portrait orientation at 12.5 fps. There is software and hardware to convert NTSC/PAL to 32 or 60 line systems, some of which are color. Bandwidth of 10 KHz is required.
nbtv.org (http://nbtv.org)
Some software...
http://users.tpg.com.au/users/gmillard/nbtv/nbtv.htm (http://users.tpg.com.au/users/gmillard/nbtv/nbtv.htm)
Also, check out some of the demos on youtube.
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