Pi Zero feeding - bizarre statistics, any ideas?

[wiedehopf]

Well if you would run Linux on the laptop, you could check :P

The range is calculated by the feed software i believe, it gets the location from the servers.
Calculating a distance is not hard.

You need much more consistent signal to get a range on the website though, it only counts aircraft you receive consistently for let's say 30 seconds or so.
For the --interactive dump1090 needs a position configured somewhere.

If you want to it right, you'll need a new dongle anyway and optimally a Raspberry Pi.

Have you optimized your antenna? https://forum.flightradar24.com/thre...h-DVB-T-Dongle

[aka_pseudonym]

You'll need to run some Linux on the Macbook, but i don't suppose that's an issue?

And the Y-lead is nice, but it might introduce extra noise on the USB line i suppose.

You can try with a 6.7 cm paperclip in the SMA connector of the dongle instead of your current antenna.
That should exclude a bad antenna.

Thanks for the ideas wiedehopf. The OSX software off the sharing page is actually a complete integrated package. Unzip it, click to start it, and off it goes. Nothing more needed so whoever put that together - five stars!

Change of question now. How/where is range calculated in the feed software?

I had a slight improvement using OSX rather than the Pi Zero but still nothing like it should be. 15nm instead of 0nm. So I stopped the feed software and just ran dump1090 using --interactive to get up the terminal display. And almost immediately it was showing an aircraft which was 53 miles away line of sight according to google maps. I simply noted the Hex and looked to see where it was on the FR24 main display.

It was a full set of data - Hex, Flight, Altitude, Speed, Lat, Long, Track, Messages, Seen. With the "Seen" being a low number of seconds and messages in the hundreds. So the dongle is receiving everything correctly. It's getting passed to dump1090 correctly. But it can't work out range from the signal strength as the aerial would make too much difference. So I presume it's being computed from the aircraft's co-ordinates and my co-ordinates (which are right and show correctly on my FR24 statistics page).

So where is that worked out? In the dongle? In the feeding software? Or at the FR24 servers? I can't believe it'd be the last as it would need pointless amounts of computing power for everyone feeding. And I can't believe it'd be my computer as I wouldn't have a Macbook and a Pi Zero which had both failed their basic Maths. So I guess it must be worked out in the dongle. But that doesn't really make sense either because when it's all set up and you put in the dongle's co-ordinates isn't that just sent to FR24 - and I don't think you even have to put them in if you don't choose to use MLAT? I'm not sure even dump1090 knows them when run by itself.

I'm confused now.

[wiedehopf]

You'll need to run some Linux on the Macbook, but i don't suppose that's an issue?

And the Y-lead is nice, but it might introduce extra noise on the USB line i suppose.

You can try with a 6.7 cm paperclip in the SMA connector of the dongle instead of your current antenna.
That should exclude a bad antenna.

[aka_pseudonym]

There is significant voltage drop in the cable to the pizero and in the pizero to the USB port and then another adapter.

I'd recommend another pi with proper USB ports.

Get a green radarbox dongle, they have a builtin filter/amplifier and are quite cheap.

Hard to say what the problem is exactly.
You can always try using the dongle via a powered USB hub if you have one.

I'm actually using a Y-lead to a single port on the Pi Zero - quite acceptable method according to the documentation! So the voltage at the dongle is identical to the voltage for the Pi and they are both 5.1V so I don't think that's the problem.

But your reply has made me think I'm being somewhat stupid. I have an old Macbook so I could set it up on that and see if the dongle still performs as it did with a Windows laptop. That'd be the sensible way forward. Process of elimination. Thanks for switching my brain on!

[wiedehopf]

There is significant voltage drop in the cable to the pizero and in the pizero to the USB port and then another adapter.

I'd recommend another pi with proper USB ports.

Get a green radarbox dongle, they have a builtin filter/amplifier and are quite cheap.

Hard to say what the problem is exactly.
You can always try using the dongle via a powered USB hub if you have one.

[aka_pseudonym]

I've posted about this before but it has now become ridiculous!

I fed with a 1st generation Pi B, then moved to Windows. Things stayed mostly the same with a range of 50NM or so. It's never more as I have mountains all around me.

When Windows was ousted I switched to a Pi Zero and my range went down a fair bit. But it has now sunk to 0nm. As of this moment my statistics show:

Aircraft seen: 108
Positions reported: 61
Maximum distance: 0nm
Hits reported: 1,248

Now I'm pretty sure 108 planes haven't flown directly overhead in the last 12 hours or so, and even if they had they'd be at 30,000ft plus which, in itself, is over 5 miles. I'm a couple of hundred miles from a major airport and not really on a major flight path unless there are odd weather systems being avoided. So 108 aircraft and 1,248 hits sounds as if it could be about right. But only 61 positions and 0nm doesn't.

Should I suspect the dongle (RTL-SDR) or the Pi Zero? Power supply is checked out and fine, the antenna hasn't moved since I started feeding in about 2015. Any advice most welcome, thank you.