FlightAware Discussions

Multilateration and

Hi everyone, just joined Flight Aware this morning and I have a couple of questions. The first one is How do I enable MLAT?, and the second is what is the best aerial for ADSB?.
At the moment I am using a RPi 3B with a NooElecNESDR Smart with a weird(to me) aerial that I made yesterday( if i remember its 1/4 wave with ground plane, whatever that means, I saw the thing on Youtube) its not doing that bad as Ive picked up a few aircraft just off the Thames and North Norfolk( Im in Soliull) but like a lot of people I think it could do better hence the aerial question.
Im a complete novice to this ADSB lark and would like to make my own aerial so…any suggestions??.

Chris

Enable MLAT requires that you are setting up your location properly. This can be done in your profile You have a gear on the right side of the orange bar:
image
Click on it and a box will open where you need to add your location properly by either selecting it or entering the coordinates. On next restart of Piaware MLAT should work after a couple of minutes.

I assume this device does neither have a filter nor an amplifier built in. Depending on your area this could be required for improvement of the reception.

A regular stick has a wide frequency area while for ADS-B only 1090 MHz is relevant. So it’s always a good idea to filter everything out. I would suggest to read the different threads here

For the antenna you can go with a DIY, there are also good threads about it in the Forum

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Thank you for the reply, you were spot on and it is now working. I think I am going for a home built antenna( Colinear ) and will look at the filter/amplifier as well,thanks for your help.
Expect more questions.

Chris

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Start with a quarter wave so you have a comparison when building the colinear.
At least then you notice if the colinear didn’t quite work and has bad performance.

These two should be an easy build:
Three Easy DIY Antennas for Beginners - #2 by abcd567
QUICK SPIDER - No Soldering, No Connector

If you already have such an antenna, try tuning the whip a bit (changing whip length for example by cutting the whip and then attaching another part that can be moved up / down by soldering).
I personally ended up with a whip at 65 mm instead of 68 mm and it made a difference.

Instead of the typical coax colinears also take a look at this colinear: G7RGQ Antenna 1090MHz

When comparing antennas or tuning it a bit there are a quite a few tools that can be helpful in regards to judging ADS-B reception.
Due to obvious bias i’ll list some stuff i maintain: graphs1090
Also useful in my opinion: tar1090 pTracks feature and displaying the heywhatsthat range outline, see the tar1090 github page for installation and how to use those features.
You’ll find links to tar1090 and graphs1090 here:
Raspbian Lite: ADS B receiver · wiedehopf/adsb-wiki Wiki · GitHub

(graphs1090 and tar1090 will work fine with dump1090-fa and won’t disrupt any feed client you might have)

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