HFU HF Underground
Technical Topics => SDR - Software Defined Radio => Topic started by: NJQA on November 16, 2021, 1746 UTC
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The latest software build for the KiwiSDR has added a HFDL decoder.
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Yes.
I have no previous experience with HFDL but have been using it over the past two days. I don't completely understand every detail in all the messages but I can get the gist and it's interesting anyway. The map feature is cool.
(https://i.imgur.com/krvPj5v.png)
One thing I need confirmed or denied: uplink messages come from ground stations (GS) only and downlink messages come from the airplanes only? It looks like it but I'm not 100% clear on that. Perhaps I missed it in here but it's not clear to me:
https://www.icao.int/safety/acp/inactive%20working%20groups%20library/amcp%205/item-1e.pdf (https://www.icao.int/safety/acp/inactive%20working%20groups%20library/amcp%205/item-1e.pdf)
Another question: there are for sure more civilian airplanes in the air at any one time than are "visible" on HFDL. Is HFDL optional and not required, like regular ADS-B transponders are? This (from 2019) makes it seem optional.
https://www.collinsaerospace.com/en/newsroom/News/2019/04/collins-expands-hfdl-network-first-ground-station-south-korea (https://www.collinsaerospace.com/en/newsroom/News/2019/04/collins-expands-hfdl-network-first-ground-station-south-korea)