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Aircraft nearby feeding distant antennas, not mine.

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  • Aircraft nearby feeding distant antennas, not mine.

    I did not mount my antenna as high as the provided cable allowed, out of concern for occasional high winds that sweep through in winter. However, when an aircraft practically flies over my house, as the one in this screenshot is doing, and feeding an antenna over 150 mi away, I wonder whether I'm missing something. My upload speeds are in the 8 mbps range. Does anyone have any suggestions to improve this state of affairs? This is not an isolated instance, but the most egregious I've yet seen. TIA!


    CPA96.jpg

  • #2
    You CANNOT rely on the 'radar' listed to check your coverage.

    Thats what other apps and the status page in your acct settings is for. The web display is randomly chosen.
    Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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    • #3
      How random?

      Originally posted by Oblivian View Post
      You CANNOT rely on the 'radar' listed to check your coverage.

      Thats what other apps and the status page in your acct settings is for. The web display is randomly chosen.
      Hi Oblivian, thanks for replying to this question. Like the OP I am new to feeding FR24 but have watched it for years. I have to say that it has never looked very random.

      What I do see is that the lower the feeder number, F-****1 the more likely you are to see them "credited".

      Phill

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      • #4
        In any case, with the number of receivers overlapping now (just check the new F- boxes sent out in 2015) it can't be used as an accurate representation of how your own or one in particular is doing. Or as a gauge on how far away one receiver is from you, given the alias is assigned based on the closest busiest airport - which may not infact be.

        Sure, the onboard processing makes the data on the F boxes that much more accurate and faster to be processed. But its not our system to demand how its run.

        Use VRS for local distance mapping, and don't expect to see yourself appear as one listed online for any period of time.
        Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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        • #5
          Does "for any period of time" means "any time soon"?

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          • #6
            @Oblivian,

            Sorry, but you seem to have missed my point entirely. Perhaps that's my fault.

            I know my range, signal strength and radio horizon. I'm don't need to use the "radar" display to determine any of those. My point was that your comment that the radar display was randomly chosen did not seem very random. It looks more like it starts on a list, lowest number 1st, say LEAB1 and only goes higher occasionally, perhaps after a certain number, or if the a/c is temporarily hidden from number 1.

            Do you actually know how the code works?

            Phill

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            • #7
              No. But like most, know its not accurate enough so can be ignored.

              It was going to be removed ages ago, but the backlash from statwatchers would likely be more. Its on the cards to be removed entirely in the future.
              Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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              • #8
                Hi, thanks for the reply. I can see where you are coming from.

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                • #9
                  About the F-****1's being over represented; The first feeder id issued near an airport e.g. KXXX will be F-KXXX1 or T-KXXX1. There may not be a F-KXXX2 and therefore in general it is more likely that you see feeders ending in 1 than any number.

                  Because of the overlap in coverage multiple feeders may pick up on the same aircraft. FR24 will pick data from the one with the 'best data' to plot the track and be shown as 'the radar'. 'Best' probably meaning most recent and complete. Over time 'best feeder' may change multiple times minute by minute or even seconds by seconds, but it would not be good to have the radar name flickering back and forth between a number of feeders, so FR24 will stick to the chosen one as long as it is feeding sensible data. Once it loose sight or 'falls behind' in feeding quality data, FR24 will shift to another radar name.

                  You may find that some feeders are more 'lucky' than others, constantly been the chosen one. I have found that this can be true for a while but later it can be pushed from the throne by another feeder - at random, or something. My theory is that because of slight differences in clock frequencies one feeder can fall in and out of favour as 'best data' provider.
                  You will just have to be content knowing that you are supplying useful data and most importantly playing a role in MLAT.

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                  • #10
                    Originally posted by Kpin View Post

                    Because of the overlap in coverage multiple feeders may pick up on the same aircraft. FR24 will pick data from the one with the 'best data' to plot the track and be shown as 'the radar'. 'Best' probably meaning most recent and complete. Over time 'best feeder' may change multiple times minute by minute or even seconds by seconds, but it would not be good to have the radar name flickering back and forth between a number of feeders, so FR24 will stick to the chosen one as long as it is feeding sensible data. Once it loose sight or 'falls behind' in feeding quality data, FR24 will shift to another radar name.

                    You may find that some feeders are more 'lucky' than others, constantly been the chosen one. I have found that this can be true for a while but later it can be pushed from the throne by another feeder - at random, or something. My theory is that because of slight differences in clock frequencies one feeder can fall in and out of favour as 'best data' provider.
                    You will just have to be content knowing that you are supplying useful data and most importantly playing a role in MLAT.

                    Well this is sad if you ask me
                    You certainly dont want to lose the high level of motivation of the new comers...
                    Each feeder should be used once in a while i think
                    And something close if possible.... As you described, right now a feeder can stay the same over a long period of time (>20min) just because it still sees that a/c...
                    Maybe plenty of closest feeder could report the same and make everyone happy.

                    About the F-****1's being over represented; The first feeder id issued near an airport e.g. KXXX will be F-KXXX1 or T-KXXX1. There may not be a F-KXXX2 and therefore in general it is more likely that you see feeders ending in 1 than any number.
                    I don't understand the logic here... xxxx1 may be the first but it could be bad and xxxx67 could be better in accuracy, range and latency.
                    Please explain again

                    Sure, the onboard processing makes the data on the F boxes that much more accurate and faster to be processed. But its not our system to demand how its run.
                    Faster ? A raspberry pi is plenty fast enough and is not even 10% cpu.
                    Do you mean the internet connection latency can influence it ?
                    Last edited by acid-drop; 2016-01-19, 23:51.

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                    • #11
                      I don't understand the logic here... xxxx1 may be the first but it could be bad and xxxx67 could be better in accuracy, range and latency.
                      Please explain again
                      Most airports only have one or two feeders, so statistically you see F-xxxx1 way more often than F-xxxx3 or F-xxxx21.

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                      • #12
                        And I got no idea why this wont open the 2nd page of replies...

                        /edit there it goes!
                        Posts not to be taken as official support representation - Just a helpful uploader who tinkers

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                        • #13
                          We have more than 49 currently active feeder around Amsterdam. It's a bit "stupid" to use only one and stick to it for a long time

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                          • #14
                            the F-xxxx are a fr supplied feeder they aren't going to put more than one in the same area. everyone else gets a T-xxxx number

                            USB has latency (buffers etc.) and this causes little time delays, even if you put GPS on you pi and use that you will still have that delay. Example dongle receives a signal sends it to the USB port, the pi is busy doing something (just running itself even) then takes the data from the USB and processes it. The delay comes from how long it takes to get the data from the dongle to fr24 software and the problem is this time delay changes constantly.

                            FR boxes use a FPGA to receive and process the data. This FPGA time stamps the received data when it arrives down to the micro second so any delays in the system after that don't matter because you know exactly when the data arrived and can process that accordingly you will never be able to that on a PI as things stand now.

                            hope that helps a bit
                            Last edited by SpaxmoidJAm; 2016-01-23, 09:04.
                            T-EGLF8

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                            • #15
                              How can usb latency be important when the internet connections add a huge lot more (in comparison ofc) latency to it...

                              Whatever the explanation is, i can underdtand F- have priority but as you say its only one...
                              Are you now saying that all other feeders are doing this for nothing ? Is that the message ?

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