FlightAware Discussions

My Flightaware antenna doesn't function

tomorrow I will have the antenna with me and I will try.
Thank you.
The new antenna works better but always with a low range (150km with rtl-blog lna)

If you look at the freq. map from FA antenna with out filter you will see lots of other signals. Before FA antenna about 1500 aircraft, 250K positions and 75mi range. FA antenna without filter 650 aircraft, 25K positions and less than 50mi. Now (only one day) with FA antenna and FA 1090 filter 2000 aircraft, 20mi+ and 500K positions.

So much improved!

Yesterday, i tested and it seems okay. Apparently I will settle for these 150 km of range.
however, can you tell me how can I install PlaneAlerter2 that I am not capable of and cannot find instructions?
Also, if I wanted, with four of my receivers, to carry out a multilateration, would anyone know how to do it?
@abcd567

Sorry, I have no information, and absolutely no idea about this.

Do you know how can i install PlaneAlerter2?
About Multilateration i read that exist this software but i don’t know how i can install it…
https://github.com/mutability/mlat-server -server
https://github.com/mutability/mlat-client -client

Why don’t you just join one of the MLAT networks?
FA / RB / adsbexchange?

Using mlat-server you will just have to figure out for yourself.

I’ve already joined fa/adsb hub but I find both quite imprecise. I have already purchased three dongles and I have to take the fourth one, but I don’t know how to configure it. EDIT: i’ve joined adsb exchange but i don’t know how i can receive mlat data from server

The FA robot is saying that I should let other people participate in the discussion, since I have already replied 3 times in this particular topic. So please, participate!! :neutral_face:

If you said so, I missed it. Those 4 stations must be a certain distance from each other to successfully MLAT. Is this the case? If they are close to each other, it won’t work right. I don’t remember the exact distance, 50km is in my head right now, but I don’t know if it’s correct.

MLAT results are by default pushed into 30104, typically into your local dump1090.

Now if you have multiple networks feeding mlat results they might disagree and cause ugly tracks.

MLAT can be quite imprecise, especially at low altitude or if all receivers are in the same direction as viewed from the aircraft.

It depends quite a bit on the angle difference of the receivers as viewed from the aircraft.

1km works just fine, but 3 or 4 receivers in a line won’t necessarily help.
For aircraft far away from a coast, you’ll need receivers a lot further apart for a somewhat decent MLAT.

Yep…I did not mention that as I thought it was implicit. Triangulation would be a better way to say it.

That’s great, but you failed to understand my point.
The filter and antenna combination works well at your location, but that does not dictate that a filter is required at all locations when that antenna is used.

You should ask on the adsbexchange forums, not here. The administrator of adsbexchange is actively hostile to anything FlightAware-related (I don’t understand why, but it is what it is) so trying to inter-operate with anything they do is tricky. I don’t know if they provide mlat results directly or if it is only via their web interface.

FA’s mlat system by default will loop mlat results back to 30104 as mentioned above, where they will get picked up by skyaware; or you can pick up the mlat results feed separately on port 30105 if you want.

Running your own mlat system is complex and you’re unlikely to get good results with only 4 receivers. 4 is the bare minimum and rtlsdr dongles provide poor timing accuracy (maybe +/- 0.5us on a good day); you need quite a lot of nearby receivers participating to smooth out that noise.

Unfortunately Adsbexchange feed back mlat results to localhost 30104 , exactly where Flightaware feed backs their mlat results.

Line #292 in file setup.sh at github/adsbexchange:

RESULTS="--results beast,connect,localhost:30104 --results basestation,listen,31003"

Feeding multiple mlat results to port 30104 can result in very odd behaviour of plane motion on the SkyView map. For this reason I have changed it to another port which is picked by ModeSMixer2 (running on RPi) to display adsbexchange’s mlat feed back planes.

Thank you all for the many answers.

Considering the positions I had already chosen for the receivers, the minimum distance would be about 15km and the maximum one about a little more than double. Also fortunately I would be able to position them to form almost a square

Obviously, but I think that since I would set each position of the dongles they would be much more accurate than those of ADS-B and therefore the precision of the multilateration would be greater.

What is Skyview map?

I tried to do what you say, but running the command “sudo systemctl status adsbexchange-feed” I didn’t get any changes. I simply solved it by taking the ADS-B EXCHANGE data from "
–results basestation, listen, 31003 "

I wouldn’t assume others have their position that far off.
If they put in a wrong location, normally their FA MLAT will just turn red and they won’t be used for MLAT.
It’s not impossible to run your own server, but some programming experience helps in battling any errors that might pop up.
You haven’t even tried … if you had posted a concrete error someone might help more readily.

But as obj pointed out, running your own MLAT server isn’t necessarily that useful.

To change the ports you edit the configuration file at /etc/default/adsbexchange

Anyhow to notice any change you need to restart the appropriate service or do a reboot.

You’re right, but the problem is another: I don’t really know how to try. how do i install that software?
Once I download it from github and put it on raspberrry, what do I do?

thanks, I had changed this configuration file, as previously suggested, so I restarted everything but it didn’t work

Good point.
If that is the case, you probably shouldn’t even try.
But let’s see maybe i’m too pessimistic.

First you need to remove the mlat-client from the machine you want to run mlat-server on.
Then you need all the python prerequisites as described in the readme.
Then in the directory you got from github, running
./mlat-server
will likely throw an error you might be able to fix :wink:

prerequisite install:

pip3 install numpy scipy pykalman
git clone https://github.com/Shoobx/python-graph.git /tmp/pygraph
pip3 install /tmp/pygraph/core

This can also be done for a virtualenv, you might want to google on how to do that.
A virtualenv would be required to run mlat-server while you have mlat-client installed.

What where you even trying to accomplish?
Using modesmixer as described by abcd?

Note that setup.sh will overwrite that configuration file …

1 Like

Thanks a lot, really.

It gives me this error:
/ usr / bin / env: ‘python3.4’: No such file or directory
I tried to install python and it seems to work: “python3 is already the newest version (3.7.3-1)”
But rerunning ./mlat-server I got the same error.
So I searched on google how to download the specific version 3.4 and installed it, but I get the same error

You didn’t specify which command gave you that error.