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Number of tracking aircraft vs aircraft seen

Posted: Tue Jun 12, 2018 1:30 am
by wd8knd
I'm a newbee, but learning. One thing I haven't been able to figure out is this. I see a count of 24 aircraft being tracked, but may only see half that many on the map. Why is that? Why don't I see all 24?
Thanks in advance for any help.

Re: Number of tracking aircraft vs aircraft seen

Posted: Tue Jun 12, 2018 2:13 am
by Radio Active
Most common (depending on where you are) is the aircraft you don't see are likely to be Mode S (MLAT tracked aircraft) that don't transmit position data, only ADS-B equipped aircraft will be seen, to see MLAT (positionless data) aircraft you need to either set up a MLAT client and join / send data to one of many MLAT servers around and hope there are other MLAT clients around you as it takes 3 or more MLAT receiver clients to get a position fix on these aircraft or know someone who might share MLAT data with you.

Re: Number of tracking aircraft vs aircraft seen

Posted: Wed Jul 04, 2018 9:41 am
by loww
Thats simple FR24 hide some Aircraft from different Company also the Military one.

Re: Number of tracking aircraft vs aircraft seen

Posted: Sat Jul 07, 2018 11:50 pm
by agw
As it happens I've been building up a FAQ page on the Reddit wiki (https://old.reddit.com/r/virtualradarserver/wiki/faq). I'll add this question to it because it does get asked quite a bit.

The list says it is tracking X aircraft but not all of them are shown on the map. Why?

All of the aircraft shown in the aircraft list have a Mode-S transponder. Standard Mode-S transponders transmit information like the aircraft identifier and the altitude but they do not transmit the aircraft position.

All of the aircraft shown on the map are equipped with ADSB-out as well as a Mode-S transponder. ADSB-out supplements the information that Mode-S transponders transmit, it adds more detail. Part of that extra detail is the aircraft's position.

Re: Number of tracking aircraft vs aircraft seen

Posted: Sun Jul 08, 2018 11:19 am
by loww
But quite Every Aircraft must have an Transponder in Europe. I dont know if the include send the Position. :D
I see many Glider who show up.