FA and FR24 - Differing Data


#1

Folks,

Mere curiosity as I know in electronics there are variables.

I have a Pi Zero installed with PiAware. Same device feeds FR24

Currently I average around 2000 aircraft daily with FA but FR24 is always around 50 or so less, appreciate that is only around 2.5% but curious as to why the difference, would it be something to do with quality of signal or amount of data?

Geffers


#2

Is that with or without mlat? Mlat is very likely dependent on the network you are feeding…


#3

I don’t think MLAT has anything to do with it. During the brief period I fed FR24 MLAT was not enabled, it was with FA, and I saw the same difference consistently. I remember trying to find the reason, or explanation, but do not remember if I succeeded.


#4

Both have mlat enabled. FR24 only gives totals so can’t narrow that down.

Geffers


#5

I don’t feed FR24 any longer, but something just crossed my mind. Does it use the same start and end times for the 24 hours period as FA?


#6

I think both use UTC

Any reason you stopped FR24?

Geffers


#7

Yes, I did not see a reason to do it, or any other site, except FA.:wink:

Feeding is not my interest. I feed FA in recognition of their excellent Piaware image and forum.


#8

i hope this is a related question. if a plane has a “do not track” request does it still count towards daily totals. i often see FR24 targets that don’t list registration etc. those targets show on my skyview but do not show up on the main FA site. so FR24 shows a plane with no registration and FA doesn’t show anything.


#9

100% agree with last sentence, forum and software excellent.

My main reason for feeding FR24 is, I live in UK, have a friend who lives in California, the FR24 live map of her area appears more timely that FA unfortunately. From UK I can view FR24 map of her area, see an aircraft going over and it goes over, with FA not always the case.

Geffers


#10

Interesting question. Don’t know answer but am guessing FA and FR24 both adhere to same privacy rules whereas ADSBexchange apparently do not filter.

Geffers


#11

Right now I am connected to 417 other FA feeders via mlat. If it were fewer, or different feeders,I am pretty sure I would miss some planes.

I actually I remember someone posting that his mlat numbers went down after a a mlat rebalancing (or what is called).

Another reason might that they differ in their policy of not showing planes that do not want to “seen”.

Not sure there are differences in dump1090fa and dump1090mut that could explain the difference???


#12

My understanding is that if FR24 is installed after FA, dump1090-fa is used for both. That was my case, and the difference was present.


#13

Good point about feeders for mlat, mine is synced with 388.

Geffers


#14

FA uses local time to split days. 24 uses UTC to split days.
That can be one reason.
Also they may count a different minimum amount of position reports as the threshold to you “seeing” the plane.
For example it could well be that FA waits until you have consistently “seen” a plane for 30 seconds before it even sends data about it to the server.

That’s all internals so it’s hard to say what they use as their stat criteria.


#15

Time probably not an issue for me as I am UK so close to UTC and will be exact when UK switches to GMT for winter time.

Threshold is probably the reason as you pointed out.

Geffers


#16

Aircraft have been using UTC for flight planning since the disappearance of Amelia Earhart. Different time zones was one of the issues identified after the disappearance.

I used it in the military and it is often used in Amateur radio.


#17

This is weird, been feeding FR24 from my PiAware set up for a few months now and within days of posting this thread and for the first time FR24 is now giving higher totals than FlightAware.

I haven’t altered anything, weird.

Geffers


#18

They have updated their client recently.


#19

Hmm, interesting. Would explain the change.

Thanks for update.

Geffers


#20

Noticed it while running apt-get upgrade.

Also the update tried to do some usb stuff with my receiver.
Luckily it failed and therefore didn’t break anything.
Note the configuration is to “beast” not to usb or something.