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GDL82 in Anonymous Mode?

jsharkey

Well Known Member
I have been flying my RV6 with at GDL82 for the past few weeks and have been in the habit of checking the Public ADS-B Performance Reports. Yesterday for the first time I set the the switch to Anonymous before the flight and left it there during the flight.

I wasn't sure what to expect when I requested an on-line report. Would I even get one? As it turned out I did get a report and it was no different from earlier ones including showing the system acting as a TIS-B client for most of the flight.

I assume therefore that "anonymous" means anonymous to ADS-B "in" receivers and not the ATC system. Or is something not working correctly?

Jim Sharkey
RV6 Flying since 2009
 
No, anonymous means anonymous to everyone. You have to be squawking 1200 and pin 5 (I think) has to be grounded.
GZ
 
It is possible your anonymous mode is not working. You should have seen red flags on the Call Sign field as a minimum. The FAA paper defining the fields and possible solutions for errors on the PAPR report shows this.
 
I was under the impression that all anonymous mode does is broadcast 1200 VFR rather than your N number. Not sure it actually hides anything. When flying with my buddy who uses that mode he still shows up on the traffic display just not with a tail number.
Figs
 
I?m installing a GDL82 now. Should have it ready to try in a couple of days...

From the install manual:
2.1.1 Anonymous Mode
In anonymous mode, the GDL 82 transmits a temporary address instead of the aircraft?s assigned ICAO address code, and a temporary Flight ID.

Anonymous mode should be truly anonymous when the GDL82 is transmitting both a temp ICAO address and ?VFR? instead of ?N? number.

I?m guessing the OP has a wiring problem and is not grounding pin 5.
 
From the install manual:
2.1.1 Anonymous Mode
In anonymous mode, the GDL 82 transmits a temporary address instead of the aircraft?s assigned ICAO address code, and a temporary Flight ID.

Anonymous mode should be truly anonymous when the GDL82 is transmitting both a temp ICAO address and ?VFR? instead of ?N? number.

I?m guessing the OP has a wiring problem and is not grounding pin 5.

Me too.

From a previous thread...a record of the transmitted output at initial power up while operating on the original software. Lines 3 thru 6 are my true ICAO code and N#, after which the system switched to anonymous mode and transmitted a random code. PLEASE NOTE, Garmin changed the software so the GDL-82 no longer transmits the real ICAO code at power up. Now a record would show the random code only. (Thanks Garmin!).

GDL-82%20Output%20CSV%20File.jpg
 
Make sure you have the latest software update from September of last year. Ver. 2372.01. It makes anonymous mode work from power up. The older versions delayed anonymous for enough time to make it not as effective. You will use the GDL 8X software tool to do the update (takes 7 to 15 minutes to update depending on I don't know what). I like to do this update prior to final configuration because some of the fields have changed. If you are using a panel navigator for position the GDL 82 may stop getting position from the unit until you go back and configure the data type in the navigator. I found this out the hard way after having a successful install go down after updating the Navigator and GDL 82.

Also, make sure to select the anonymous mode option box from within the GDL 8X installation tool software. It is unchecked by default. If this wasn't done at time of installation it won't matter where your switch is positioned. It has to be enabled. Once enabled it will stay that way. While you are at it make sure the boxes for both UAT and 1090ES "in" are checked. No sense in limiting your in signals.

If I install a GDL 82 in an airplane with the anonymous switch sometimes I leave that option unchecked to make sure the pilot doesn't mess up the initial PAPR report. Once I get a good PAPR I go back in and enable the switch.

Jim
 
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....going to check wiring!

May have switched optional output wires - the Fault Light and the Anonymous Switch!

Easy check and fix if that is the problem.

The PAPR User's Guide is pretty explicit in the fault table. Should have checked there first!

The report will say:

"No flight data found for specified date"

if

"? Aircraft transmitting wrong ICAO 24-bit address
? Late day flight (flight times are recorded in UTC)
? Flight with UAT system operated in anonymous mode.
? Possible ADS-B service outage
? Aircraft not transmitting ADS-B data"
 
I was under the impression that all anonymous mode does is broadcast 1200 VFR rather than your N number. Not sure it actually hides anything. When flying with my buddy who uses that mode he still shows up on the traffic display just not with a tail number.
Figs

Figs,

The only thing anonymous mode hides is the identity of the aircraft and aircraft owner. Aside from that the aircraft is completely visible to other aircraft and ATC for traffic awareness purposes so there is no compromise to safety. When squawking VFR with anonymous mode enabled even ATC and FAA home office can't see your identity from the out transmission. That doesn't mean they don't have other very effective ways to track you down quickly in case of incident or emergency. They almost don't need your ADS-B information to do that, it just saves them a little time. But that estranged ex-girlfriend or business competitor can't keep track of you. Nor could anybody stalk an aircraft owner. More importantly local governments can't send you fees or taxes based on their own receivers. For a while Florida was famous for sending tax bills to aircraft who overflew their state based on some geek bureaucrat's portable ADS-B receiver. About 3 years ago they sent excise tax bills based on appraised value to airshow exhibitors who brought demonstration airplanes to Sun-N-Fun. Let 'em eat cake and stay anonymous.

Jim
 
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Configuration Updated

I addd the Anonymous switch after I had configured the system using the GDL82 Install App. There is a configuration setting in the App to activate Anonymous operation. I hadn't activated it in the initial installation. Reconfiguring has fixed the problem. RTFM as they say! :D
 
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