Re: ADSBSpy Output format


RE: The statement you took exception to was part of a cut and paste from the most informative ADS-B decoding site I found on a quick search. Argue with that person. specifically this page paragraph 1.1.4:

I've just realised - that site is (currently) correct since it is specifically referring to ADS-B, which uses DF-17 and DF-18. DF-17 and DF-18 are both (currently) covered by (CRC = 0). The web-site does not refer to DF-11, or any of the other Downlink Frames.

However, you will notice that the last line of the first table calls the last 24 bits of the message the "Parity/Interrogator ID" . The reason for this is that there is support for II/SI encoding in the parity field, meaning that in the future they may allow CRC to be any value from 1 to 79 for DF-18 and DF-17. I've not looked to see if any aircraft/radar sites support/implement this yet, but in principle it appears they could.

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