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Thread: Statistics data: max range equals average range

  1. #1
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    Statistics data: max range equals average range

    Hi, i have just seen that T-EDDK145 has 349 as max range and 349 as average range.
    I entered it's data page and i see in the histogram that the current received distance max contacts is around 50~100 nm.
    So how can the average range be equal to the max range?

    Thanks for aswer.
    Fabrizio

  2. #2
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    I believe average range is a result of the max range recorded each day for 30 days and then divided by 30.


    Example:

    Day 1: Max range recorded: 300nm
    Day 2: Max range recorded: 200nm
    Day 3: Max range recorded: 200nm
    Day 4: Max range recorded: 250nm
    Day 5: Max range recorded: 200nm

    Average range of these 5 days: 230nm



    I'm not 100% certain on this tho… Someone correct me if I'm wrong.

  3. #3
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    I too am a bit suspicious of some of the stats. I have had my maximum range hit the magic 349 nm mark but struggle to get the average over 210. I suppose if there are large numbers of flights going directly over ones receiver then that average must be lowered and there is nothing that can be done about it.
    Today I saw these feeders stats (I won't name it but its in the UK as I am) which has a very high Aircraft Seen number. I don't see how it can be correct. Compare these 2 screen shots:-
    High aircraft numbers.JPG

    and mine on a good day:-
    My aircraft.JPG

    I wonder if there are bugs in the FR24 database

  4. #4
    Captain abcd567's Avatar
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    If anyone is not confident of FR24 stats, AND is using RPi to feed FR24, he/she can have his own stats generated locally on RPi. Follow the method given in the thread below.

    NOTE:
    (1) When the script "install.sh" is run, it will offer lot of options to install so many things. Keep on saying NO to all till at the end it will offer WEB PORTAL. Accept Web Portal, and Performance Graphs (which are included in web portal) will be installed.

    (2) When you choose Web Portal, it will offer "Advance Options". Say NO to it, else it will install a database which will continously save all flight data, filling your microSD card in due course, and will also shorten its life due to continous writes.

    Automated Installation of Dump1090-Mutability, Data Feeders, and Performance Graphs

    .

    Monthly Max Range Graph
    dump1090-localhost-range_imperial_nautical-30d.png


    It has buttons for displaying 6hrs, daily, weekly, monthly, and yearly graphs.
    Web Portal Graphs Page.jpg

    .
    Last edited by abcd567; 2018-12-16 at 17:05.

  5. #5
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    Interesting though that all the radars at the top of the list are seeing less than 5000 aircraft a day and most of us are getting in the mid 2000's to see one with entries of 37,000 aircraft per day but with only 360,000 positions - something not right there.

  6. #6
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    Another thing I find intriguing. Currently worldwide, 717 radars have a maximum range of 349nm. not one of 350 or 351 or 353. The radio horizon to an aircraft at 45000 feet (not many are) from my location with a clear view to the northeast is 295nm. To get a range of 349nm I would need to be at 40,000 feet to receive a signal from an aircraft also at that height. I do get distances of 348 or 349nm on a few days each month but I suspect data errors somewhere. I don't say it's IMPOSSIBLE to receive from that distance, there's always the possibility of tropospheric ducting increasing range but 349nm every day with no variations over time just doesn't look right.

  7. #7
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    You won’t ever see ranges of more than 349nm on FR24 as the software has that figure as a hard limit and cuts anything above this down to 349, however it appears that they use the higher figures when calculating the average (which is also capped at 349nm)

    Quote Originally Posted by Scroggie View Post
    Another thing I find intriguing. Currently worldwide, 717 radars have a maximum range of 349nm. not one of 350 or 351 or 353. The radio horizon to an aircraft at 45000 feet (not many are) from my location with a clear view to the northeast is 295nm. To get a range of 349nm I would need to be at 40,000 feet to receive a signal from an aircraft also at that height. I do get distances of 348 or 349nm on a few days each month but I suspect data errors somewhere. I don't say it's IMPOSSIBLE to receive from that distance, there's always the possibility of tropospheric ducting increasing range but 349nm every day with no variations over time just doesn't look right.
    Last edited by F-EGLF1; 2018-12-30 at 15:20.
    FR24 F-EGLF1, Blitzortung station 878, OGN Aldersht2, PilotAware PWAldersht, PlanePlotter M7.

  8. #8
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    Quote Originally Posted by MacchiaNera View Post
    Hi, i have just seen that T-EDDK145 has 349 as max range and 349 as average range.
    I entered it's data page and i see in the histogram that the current received distance max contacts is around 50~100 nm.
    So how can the average range be equal to the max range?

    Thanks for aswer.
    Fabrizio
    Hi Fabrizio!

    On my opinion FR24's Avg Range calculation is simplier then we believe. I think this calculation based on polar plot data, not on histogram's data.
    I collected my last 30 days FR24 statistics and entered the Polar plot data into an Excel tablet. With the range of 8 directions it calculated a daily and 30 days average range and the result is same as I can see in FR24 Global statistics.
    As I think, this is the reason why are in some cases very similar the max range and average range. If the antenna can recieve ADS-B signals very well (nearly to max 349 NM) in all direction, then the max and average distance are almost equal. When distances are less,(in one or more direction) the difference is greater because in FR24 Global Statistics we can see the highest range of last 30 days, not the average max range of 30 days.
    Please check it!

    stat.jpg

  9. #9
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    Quote Originally Posted by MacchiaNera View Post
    Hi, i have just seen that T-EDDK145 has 349 as max range and 349 as average range.
    I entered it's data page and i see in the histogram that the current received distance max contacts is around 50~100 nm.
    So how can the average range be equal to the max range?

    Thanks for aswer.
    Fabrizio
    Hi Fabrizio!

    On my opinion FR24's Avg Range calculation is simplier then we believe. I think this calculation based on polar plot data, not on histogram's data.
    I collected my last 30 days FR24 statistics and entered the Polar plot data into an Excel tablet. With the range of 8 directions it calculated a daily and 30 days average range and the result is same as I can see in FR24 Global statistics.
    As I think, this is the reason why are in some cases very similar the max range and average range. If the antenna can recieve ADS-B signals very well (nearly to max 349 NM) in all direction, then the max and average distance are almost equal. When distances are less,(in one or more direction) the difference is greater because in FR24 Global Statistics we can see the highest range of last 30 days, not the average max range of 30 days.
    Please check it!

    stat.jpg

  10. #10
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    This seems a bit strange too:-
    T-EGMD4.JPG
    Over 30,000 aircraft in a day? The best I've seen in 24 hours has been just over a tenth of that!

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