New user, need help with the MLAT function

Hello everybody,

I have recently assembled an ADS-B reciever with a raspberry pi 2 model B computer. I first started testing it yesterday with one of the first versions of Piaware (v1.2 I think). This morning I upgraded it to one of the latest versions (v2.1) which should include MLAT. On my stats page I enabled MLAT and it says that I am synchronized with 6 nearby recievers. I spent the whole day with my computer and my ADS-B on, I haven’t caught a single aircraft with MLAT yet (no purple planes at all). I have checked with flightradar 24 and there were aircraft flying near my location without ADS-B (only mode S transpoder), it said T-MLAT radar in their descriptions. My antenna is placed indoors (to poor for an outdoor antenna lol, still a student) and clearly recognizes ADS-B equiped aircraft within a 60/120 mile radius. Is this normal or I didn’t configure my software properly ?
Thanks in avance for your help :wink:

Regards Andre.

hi andre,

there are different things that could went wrong e.g. the new piaware uses another port for mlat results (30104) than older versions of piaware and dump1090 use (30004) - see this thread you could look into your piaware log

cat /tmp/piaware.out

and post the result here.

what is your actual dump1090 version? there are older versions that won’t display mlat results.

another option - if you have a second sd-card - try the ‘plug and play solution’ sd-card image

have fun

p.s. regarding your antenna you find very good tips from user abcd to improve reception without money:

Another thing is even though you are synchronized with 6 sites, 4 of them have to be seeing the same aircraft. So if you and 2 others see it, but the other four don’t see it, you won’t track it. I would probably suspect the flightaware servers though. They have been a little on the fritz lately.

Good morning guys (if you’re in europe),

Thanks for the answers, after typing your code in my pi it was written that I had;
piaware version 2.1-3, process ID 1970, my system is a Linux piaware 3.18.5-v7, my program is listening ADS-B data on port 30005 (apparently the old version !), it’s reaching the server on

I honestly absolutely don’t know how to check my dump 1090 version, I guess it’s the old one. I will try to update all of these things but I am still waiting for a response from you if it doesn’t bother you. Your help is welcome. :wink:

Regards Andre.

BTW (sorry for double post), regarding the post about DIY antennas, I have already seen it and was surprised about how simple it was to build one. I will maybe attempt to do this in the future but for now I will stick with my basic indoor antenna it’s good enough :slight_smile:


if you have a second sd-card my recommendation still is to install the flightaware image. then you have a stable and common basis for further improvements. most things will work out of the box - and it is much less time consuming than tweaking here and there on an unknown installation.

regarding abcds antenna tips - if you have the small fixed standard antenna - just cutting off the top like shown brings improvements of about 20%


Congrats Tom, you were right my dump 1090 was outdated, I updated EVERYTHING in my ADS-B stats page and I’ve started recieving several aircraft via MLAT. Thanks a lot I will read that post again, +20% seems very intersting. Thanks again.

Regards Andre.

perfect :slight_smile: have a nice weekend

p.s. this is abcds post about cutting top of standard antenna: