FlightAware Discussions

MLAT enabled but no MLAT - Namibia


#1

We are 8 feeders in Namibia of which 7 are MLAT enabled. We normally had around 5 MLAT trackings a week but lately nothing. On my “Nearby Sites” all of us are marked with an X (not enabled) despite being enabled.
I also note that from my skyview, flights with full details return an “unknown flight” when clicked upon. However, at the same time the very same flight in my “Flights with position from this feeder…” give me the correct and full details of the flight. Anybody with the same problems?


#2

In your location, based on the average distance to the planes you can “see”, there are only three viable MLAT sites. MLAT requires four or more. The ones that are bunched together (located at 12, 13, 14 mi of you) cannot achieve the necessary accuracy by themselves.
If one of those sites in the triangle (20 mile diameter) loses range for some reason, then all MLAT fails. I think that the loss of the PiAware site (10 days ago) did that to you (it’s the white dot on map).

In this case, you need to raise the antenna to achieve some 160 km range, to be able to MLAT with the far-away people. I think that Jurgen site already reaches there, he needs one more “helper” - you.


#3

It was probably working until the white piaware station started not working:

(https://flightaware.com/adsb/stats/user/reefwarrior#stats-65557)

Better drive over and fix reefwarriors pi :stuck_out_tongue_winking_eye:


#4

Reefwarriors’ site was never MLAT enabled. The main MLAT contributors are the two at the coast (with excellent coverage toward us in the highlands), the one in the north and then one or two of the three in the cluster nearby. If looking at the number of MLAT positions recorded per event, it always seemed as if the “anchor site” is either one of the coastal guys, my site or one of the sites (Jurgen) in the cluster, with the others coming in at a lesser recorded number. If looking at our normal main traffic patterns (north/south), all of the above share coverage in that area.

I am surrounded with mountains and cannot get better range but it worked before as is. Could the non communication between my skyview and positions recorded, as explained in my original post, play any role in cutting me out of the MLAT group?


#5

Does that happen for all the flights? That indeed sounds strange.
And that didn’t happen before?

But it could well be changes on the website not allowing you to find flights with the ModeS code only.
I believe that was possible and they disabled it.

So now the Flight Ident being broadcast by the airplane needs to be correct.

But i’m not sure how that could impact MLAT. If your receiver is somehow not working properly anymore that could indeed be a problem but i’m not sure those links are an indication of that.

Could you provide a screenshot of a flight in SkyView with the problem you described?
And maybe check if the close by feeders are having the same problem?

Anyway might still be good to get @reefwarrior to enable his MLAT by configuring his location so maybe MLAT works again :slight_smile:

Only staff can really look into such MLAT issues. Not sure if obj has time to look into it maybe you get lucky!


#6

It happened again today. It seems to affect only this flight SA8144 which is an SA Airlink flight, Embraer ERJ 170 on the daily Johannesburg - Walvis Bay route.


#7

That’s not an issue with your feeder.

That’s just the flightaware webpage being clunky and only accepting
SAA8144 as ident (not SA8144)

The flight is probably broadcasting the wrong identification or the data source flightaware is using for destination and other stuff is giving flightaware wrong information on the flight.