Missing aircrafts between dump1090 and FR24 feeder

[DjMomo]

Hello,

I've recently installed dump1090 and FR24 on a RPi. This works well, but, not all aircrafts reported by dump1090 with a valid position are "seen" by FR24 feed. Have a look on these pictures : dump1090 report 20+ aircrafts but only 6 for FR24 feed at the same time.
Capture d’écran 2016-07-08 à 08.08.22.jpg Capture d’écran 2016-07-08 à 08.08.01.jpg

Do you know why this difference exists ? I'm the only one with this problem ?

[F-EGLF1]

Several of the aircraft you are seeing are position less, if they are not transmitting position or call sign then they will not be shown (if there are sufficient stations in your locality then some of the position less ones could be tracked with MLAT providing they are transmitting a call sign) also most military and many private aircraft have requested not to be tracked, this is something FR24 honours unlike some tracking sites.

[Sam26K]

It looks like all but six have coordinates defined, also there are a lot more than 6 shown on the map. A distance number indicates full position info.
I don't know why the dump1090 list is larger than the feeder list but my guess is it may have something to do with the FR24 server not requesting data for every a/c in range.

Edit: I use VRS to monitor local traffic.
http://www.virtualradarserver.co.uk/.

Definitely not all the data returned by dump1090 is fed to FR24 by every feeder.

[Oblivian]

The 'seen' column is a dead giveaway too. You are losing traffic for bursts of time. Ala not stable enough for the uploader to care as being quality data

Much like 'predict track' on various software. Dump1090 will often hold icons onscreen for up to 2 minutes after loss