What position, exactly, am I setting?

Hello All,

I’ve just set up an ADS-B receiver, following the list of suggested parts in the FAQ. As soon as I’ve finalized the antenna mounting, I will need to set location and altitude for MLAT. I understand that the antenna, not the rPi is what matters for location; but what part of the antenna?

Should I set location and altitude from the base of the antenna? The center? Top? Is the difference small enough(or expected error, I’m using a GPS module; but probably not a perfect one, large enough) that it doesn’t matter?


Where the center of the active bit is relative to the ground - the height doesn’t need to be too precise anyway.

The dongle itself introduces an error of somewhere around 100-150m so you don’t have to get it perfect - nearest 10m is more than enough.

Great, thanks for your help. Now I just need to finish the weatherized enclosure; and I should be all set to go!