Pi Zero feeding - bizarre statistics, any ideas?

[aka_pseudonym]

Don't think that's strange, but the statistics there are pretty limited.

I don't know how well it would run on a pi zero, but i'd recommend these graphs for statistics:

https://github.com/wiedehopf/graphs1090#graphs1090

Might be using too much CPU though.

Thanks - those graphs look ultra comprehensive!

You're right about the pi zero - it struggles doing mostly nothing. I have another machine with Linux Mint on so I need to set all it up on that and then have a play.

[wiedehopf]

Don't think that's strange, but the statistics there are pretty limited.

I don't know how well it would run on a pi zero, but i'd recommend these graphs for statistics:

https://github.com/wiedehopf/graphs1090#graphs1090

Might be using too much CPU though.

[aka_pseudonym]

Thanks Oblivian, wiedehopf

https://forum.flightradar24.com/members/13085-Oblivian

https://forum.flightradar24.com/members/72656-wiedehopf

Can you just tell me if this looks like a "normal" ratio of hits to positions? It's not totally representative of what I can receive because of military activity/me switching things on and off etc, but it's an "average" sample maybe:

Screenshot 2019-11-07 at 23.46.24.png

Still trying to work out what's going on!!

[aka_pseudonym]

So much postage?
From where are you trying to order?

You can get them directly from their store or from Amazon US or EU.
Shipping from their store would be cheapest i imagine.

The black ones don't have an amplifier, might as well get a 5 dollare unit from china, nothing special about those and no SMA connector which is really more robust than the MCX.

OK thanks. Yes, their store just takes me to Amazon but it is a bit cheaper than eBay sellers. I try and avoid Amazon partly because of their employment practices and partly because they use couriers and there's not a courier on the planet who will deliver to my location! Anyway, it's "fulfilled" by them so click&collect is possible. I thought the black one was probably rubbish looking at the aerial it's bundled with. Thanks for the advice.

[wiedehopf]

So much postage?
From where are you trying to order?

You can get them directly from their store or from Amazon US or EU.
Shipping from their store would be cheapest i imagine.

The black ones don't have an amplifier, might as well get a 5 dollar unit from china, nothing special about those and no SMA connector which is really more robust than the MCX.

[aka_pseudonym]

radarbox green dongle is better with interference and cheaper.

But FA dongles are also good, depending on interference an extra filter is required/improves reception.

Or best option in my opinion, this LNA together with the v3 or smartee dongle: https://www.rtl-sdr.com/new-product-...mhz-ads-b-lna/

What are the Radarbox black ones? Rubbish?!?! Green ones are more expensive than the FA orange ones where I am due to postage costs, but not by much. I've had some correspondence with FR24 support - perhaps they'll send me a free one! I'm still trying to test everything but today my military TTA has been active so nothing flying over at all - typical.

[wiedehopf]

radarbox green dongle is better with interference and cheaper.

But FA dongles are also good, depending on interference an extra filter is required/improves reception.

Or best option in my opinion, this LNA together with the v3 or smartee dongle: https://www.rtl-sdr.com/new-product-...mhz-ads-b-lna/

[aka_pseudonym]

The time column, is time since last decodable signal. If that is ever more than 0, then that's a big tell tale that you aren't getting enough for fr24 to care about in each upload.

2-4 per second. And not Evey one is a location packet. And if full off noise and not able to get the crc bit at the end. Can be non decodable

And can vary with gain.

Sent from my EML-L09 using Tapatalk

Thanks for all the information.

So I've been monitoring it just on dump1090 --interactive and even with an aircraft close by it has problems holding the "Seen" at 0 secs. Little jumps to 1 sec or more at quite regular intervals. Dump1090 on startup says the gain is set to maximum (49.4 from memory), and the aerial is where it has always been, and the Macbook running it has 500mA at the USB port for the dongle which will easily be enough, and I've cleaned all contacts with quality switch cleaner.

So does all that suggest to you the dongle is weary after nearly five years of use? It's just a DVB-T stick - Macbook says the chip is RTL2838UHIDIR. Blue! And has always got quite warm. Are the flight aware dongles the way to go?

[Oblivian]

I should point out, I believe the fa prosticks have been tuned and locked (tv sticks drift and may not tune the same twice depending on heat etc)

And filters and amps added. So in that respect they do more optimising for the signal before outputting it.

Sent from my EML-L09 using Tapatalk

[Oblivian]

Nothing. It is a radio receiver. Designed for tv.

S d r

Software, defined, radio.

What the software does is send a command to it go Change frequency and start receiving.

Dump1090 does the work. And as such is adjustable.

It gets the raw data off the frequency tuned. And decodes it. Hence the 'dump'

Everything else including fr24 uses the readable decoded data from there.

Sent from my EML-L09 using Tapatalk

[aka_pseudonym]

The time column, is time since last decodable signal. If that is ever more than 0, then that's a big tell tale that you aren't getting enough for fr24 to care about in each upload.

2-4 per second. And not Evey one is a location packet. And if full off noise and not able to get the crc bit at the end. Can be non decodable

And can vary with gain.

Sent from my EML-L09 using Tapatalk

Oh right! So does the dongle do any processing at all? Or does it just receive and amplify and shove it out to the USB port? And presumably ignore anything where the packet is incomplete or the checksum is no good? And then that is also bundled up and sent through to FR24 without any checks by the host computer?

If all that's right, was there a time when FR24 changed or improved its data checking? Maybe when Windows was depreciated? Because that would then start to make sense. And mean the dongle was actually out performing itself in my early days of feeding. Sorry for the layman's language but as I said to wiedehopf I'd like to understand the problem before replacing equipment. If my guess is near the mark and my data is and will forever be pretty much useless (and all the military have switched off their transponders anyway) I might ponder on whether to carry on.

[Oblivian]

The time column, is time since last decodable signal. If that is ever more than 0, then that's a big tell tale that you aren't getting enough for fr24 to care about in each upload.

2-4 per second. And not Evey one is a location packet. And if full off noise and not able to get the crc bit at the end. Can be non decodable

And can vary with gain.

Sent from my EML-L09 using Tapatalk

[aka_pseudonym]

Well you didn't respond to the antenna thread i posted.

It might just be that each time you are using a different position is what influences reception.
It's basically impossible to tell what the problem is without either replacing parts or at least having reference parts to check.

Try with a can below the antenna or different antenna position.
Or just describe what kind of antenna you are using, most of the time there is room for optimization.

Little antenna! On a tin. Not the best I know but it's the same one I've been using for nearly five years, in the same spot, which gave me 50nm, then 0nm, and now 50nm again when using just dump1090 --interactive.

And likewise the dongle is performing as it should with --interactive. So logically it has to be somewhere further down the chain. Hence wondering if it's in the transmission to FR24 although my router isn't logging any errors. It's an old industrial strength BiPAC 7800DXL which probably gives more comprehensive information than almost any other ADSL router ever made! All just very strange!

[wiedehopf]

Well you didn't respond to the antenna thread i posted.

It might just be that each time you are using a different position is what influences reception.
It's basically impossible to tell what the problem is without either replacing parts or at least having reference parts to check.

Try with a can below the antenna or different antenna position.
Or just describe what kind of antenna you are using, most of the time there is room for optimization.

[aka_pseudonym]

The range is calculated by the feed software i believe, it gets the location from the servers.

That would make sense - so it shouldn't differ from one machine to another.

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.

From the basic dump1090 - not the full feeding software - I am getting consistent signals. An aircraft that was tracked when it was probably 40 miles away sent 1,226 messages. According to the internet the interval between messages can vary, but according to my stopwatch that's two minutes or more of constant data.

So, being a poor pensioner who finds everything expensive, and even more importantly for the sake of the planet, I really don't want to start replacing equipment which may not be faulty. I'm now also wondering if packets are being dropped somewhere because of my aged router or my ancient ADSL copper wire. Perhaps I should try FR24 support and see if they have any ideas.