Is there a way to log / record ADSB data locally without streaming it to ADSBExchange? I will be at an airshow without wifi (cell hotspot not available), but I still want the tracking ability. Is there a way to do this so I can play back the tracks later?
You could come up with something to pull the JSON data off the feeder and log it.
You can take a look at my implementation of a portal at jprochazka/adsb-receiver
If you are looking to implement something on your own, you can use the following Python file as a reference in order to save data to an SQLite or MySQL database using dump1090 JSON as a data source. Mind you this is not tested against Readsb which the ADS-B Exchange image uses?