FlightAware Discussions

How to get ads-b signals from aircrafts on ground/runway

yes. I put gain 30 which was the shown command earlier.

This is the result with gain 30

That’s still strong mobile signals compared to 1090 MHz.

Building stuff yourself at those frequencies is just complicated :confused:

You are correct. Soldering this saw filter created doubts about my age. Ran RTL SDR scanner and it shows like this. This is from alleged signal generator hence cannot be taken as perfect but some what nearer to the actual.

The mobile signals enters even without connecting any wire or even SMA adaptor to the dongle. No respite from it.

The filter helped some.

But according to that diagram, it’s either a bad SAW filter or got damaged when soldering.
Or the way you soldered the SAW filter compromises its performance somehow.

The above spectrum was using the alleged signal generator and cables connected to RTL SDR. I was telling that even without connecting anything the RTL SDR dongle picks up mobile signal itself. That was general update and it was not related to SAW filter nor to this spectrum image…

Can it die partially? Because with SAW filter FM, Airband, Tetra all reduced alot. Airband extinct and FM & Tetra became very low.Known mistake may be with the saw was I had to solder 3 legs on both sides and used it on old cable tv coupler (inside board was removed and just the pins were kept). So legs will be little long like 1/2 inch both sides so 1 inch totally.

Now wrapped the RTL generic dongle with aluminium foil. Mobile signals reduced to some extent but still it is more powerful than ADSB.

Try filtering the power line. - http://andybrown.me.uk/2015/07/24/usb-filtering/
schematic

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Thanks alot. I will try this.

As others have said, your primary issue is buildings / line-of-site. You might be able to improve your GND aircraft detection by setting up several NOOELEC dongles attached to 1/4 wave ground plane antennas, each in a different window of your house / apartment so they each receive different ADS-B reflections.

With all 3 feeding Flightaware.com, maybe you’ll get better GND coverage versus trying to optimize 1 ADS-B receiver.

The other potential plus to using the 1/4 wave ground plane antennas is that they naturally filter the signals below 1090 …

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Good idea. In a position yagi picks some gnd but 1/4 isn’t picking much. So I should have to use multiple yagi. But will a parked aircraft where passengers boarding etc.,. will have ADSB ON?

The pilot decides the ‘timing’, I guess. Some ground vehicles have ADS-B transponders, don’t they?

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Not while boarding, but at a controlled airport, it should be on while taxiing.

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It depends.

JetBlue and FedEx like to keep their transponders on pretty much all the time.

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In nearby Bangalore Airport I happen to see trafic named ‘Followme’ on fr24. But for my airport hardly much GND traffic is shown. So it seems still long way to go for me.

Some countries have unofficial “Don’t follow me” vehicles. It’s to prevent people from trying to get on a plane after it left the gate.:upside_down_face:

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Pre Amplifier failed near the Yagi. This time will look into quality preamp and dongle. Mean while, FA has said that they are looking for “host feeder” to monitor ground traffic. I was informed that the equipment for this is optimized for this purpose.

What is that optimized equipment?

My guess is that they use something that isn’t prone to overload due to the close by strong signals.
Good filtering to cope with the airband transmissions and other interference.

The ModeSBeast or Radarcape components they have in their FlightFeeder fit that bill.

rtl-sdr dongles have less dynamic range, that means you can either adjust them to receive mostly weak or mostly strong signals, not both at the same time.

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Any one hosting this optimized equipment? Many months gone but I am getting standard reply from them that they don’t presently have one in stock for me to host!

Essentially a FlightFeeder Orange with manually adjusted gain. They are intended for on-airport (or very close to airport) installations.

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Antenna is same like blue feeder?