Eddie Cesnalis Posted June 19 Report Share Posted June 19 I have Garmin: GDL50(ADS-b in); GTX327(transponder); Aera 760 GPS. I only see other traffic not myself too. Is it the GDL or the 760 that ignores my planes ADS-B broadcast? I have had my Avionix EchoUAT install improved with a new power supply but I don't think I'm broadcasting. Can I easily use my tablet running Garmin Pilot and the GDL50 to see myself as ADS-B traffic? I also don't know when it starts broadcasting as in do I have to be ariborne? Quote Link to comment Share on other sites More sharing options...
Eddie Cesnalis Posted June 19 Author Report Share Posted June 19 I guess I'm talking about ghosting. the groundstation's broadcast includes me and it can't be filtered so supression isn't the answer. apparrantly the icao hexcode needs to match in the adsb transmitter and the reciever to supress ghosting. How do I most easily defeat the supressing to see the ghosting to confirm my own broadcast? Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted June 20 Report Share Posted June 20 I believe it’s done in software, the device filters out your own target based on target position correlated with position and speed of your aircraft. If they are close enough to the same the targets gets filtered out and not displayed. Some devices are better at this than others. I have a GDL-50 and a Stratux in my airplane. If I’m in a steep turn for more than a few seconds the GDL-50 is fine, but the Stratux will often show a ghost target lagging in the turn. I imagine the Stratux has a slower processor and samples less often, as well as having an inferior traffic filtering algorithm. Quote Link to comment Share on other sites More sharing options...
Ulmo133 Posted June 20 Report Share Posted June 20 Generally inside your devices the callsign of your plane is in the parameter. So when this devices see you, they ignore you. Quote Link to comment Share on other sites More sharing options...
Eddie Cesnalis Posted June 20 Author Report Share Posted June 20 13 hours ago, FlyingMonkey said: I believe it’s done in software Yes, I've learned that ghost supression is done by having the icao id hexcode in both the ADS-B in and out and therefor ghosting isn't an issue if you have an in/out unit. Do you know how to access the gdl50 configuration? I reason if I can temprarily change or delete the icao code I should see myself as traffic. Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted June 20 Report Share Posted June 20 3 hours ago, Ulmo133 said: Generally inside your devices the callsign of your plane is in the parameter. So when this devices see you, they ignore you. There has to be more to it than that. I have gotten ghosting multiple times, even when I've told my Stratux my aircraft ID. I think it's a combination of target return position data correlated to your position from your GPS. ID might figure into it, but it's not all there is, at least not for some devices. As I mentioned, I think how fast the device processes information and any "lag" can have a big impact. Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted June 20 Report Share Posted June 20 2 hours ago, Eddie Cesnalis said: Yes, I've learned that ghost supression is done by having the icao id hexcode in both the ADS-B in and out and therefor ghosting isn't an issue if you have an in/out unit. Do you know how to access the gdl50 configuration? I reason if I can temprarily change or delete the icao code I should see myself as traffic. IIRC I have not put my code into the GDL-50 (but it connects to my iPad and might get my N-Number from there), yet it never shows me ghost targets. The Stratux, conversely, has my hex code and still ghosts pretty regularly. I think it's mostly a matter of how good the device's filter algorithm is at correlating a target to your own aircraft. Also, I usually fly in anonymous mode, which blocks tail number information and I think generates a random hex code, yet still don't get ghosting. My IN/OUT device is a GDL-82. Quote Link to comment Share on other sites More sharing options...
Warmi Posted June 21 Report Share Posted June 21 ADSB format does reserve 3 bytes for ICAO hex code so the only question ..is it always transmitted and does it point to your hex code or a placeholder ( depending on the anonymous mode settings ) Quote Link to comment Share on other sites More sharing options...
Anticept Posted June 21 Report Share Posted June 21 You cannot stop the ghosting if there is an ATC malfunction with ADS-R (rebroadcast). Near wilmington ohio, they had issues for almost a year with rebroadcasting creating shadows because it was out of spec. ADS-B works by broadcasting every second. It is not an interrogative system. It is always transmitting. ADS-R is the system used to rebroadcast traffic picked up by ground based ADS-B receivers. Its purpose is to show traffic on the other frequency, which is why if you only have single channel ads-b in, you can still see the other frequency traffic near ADS-R sites. You can test your system with PAPR reports. https://adsbperformance.faa.gov/PAPRRequest.aspx You can also have issues with TIS-B traffic creating ghosts resulting from secondary surveillance radar interrogating your transponder. This too should be filtered out as the TIS-B broadcast has your tail number hex code, byt badly installed or incompatible installations can cause issues too. Most commonly, mode S transponders don't mesh well with independent ADS-B devices in anonymous mode. Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted June 21 Report Share Posted June 21 Good info and that all makes sense, thanks Corey. Quote Link to comment Share on other sites More sharing options...
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