iFly GPS Forum

I'm pretty sure there is no anonymous mode allowed for Mode S units.

A quick search turned up this link: https://www.faa.gov/nextgen/equipadsb/resources/faq/ from which I pull this quote (I added the boldface to the last few sentences): "ADS-B Out equipment transmits information about the aircraft's location, ground speed and other data once per second. The broadcast includes the aircraft's unique ICAO address, which for a US registered aircraft is associated with its tail number, as well as the transmission of aircraft's flight ID, which for GA aircraft is generally the registration "N" number, or for commercial/government operator's, their call sign or airline flight number. Air traffic controllers can immediately see this information if they desire, however the controller has display options where they can suppress the N-number for VFR aircraft that are not receiving flight following services, and some controllers will set these options to "declutter" their display. Additionally, GA operators that employ UAT transceivers have the option in VFR operations, when they are squawking 1200 and flying below FL180, to select "anonymous mode", which enables the transceiver to broadcast a randomized flight ID and pseudo-ICAO address. The transceiver reverts back automatically to the assigned ICAO address and default flight ID when the beacon code is changed from 1200."

But as far as the reason goes for implementing it at all, I believe it's just that not everyone is comfortable with the government tracking their every move, or getting a letter from the FAA due to some accidental violation, such as a brief incursion into Class B for instance.  I get that.  Oh, that brings up another thing: I'm pretty sure I read somewhere that you can't use ATC services if you're in Anon Mode.  Makes sense.  [Edit: duh, you're squawking 1200]  Also, I'd worry about if you crashed.  It seems like it would be easier to find you if you were not anonymous -- they could just look up your flight track by your tail number and see where it ended.  [Edit: FAA specifically mentions this as one reason to have ADS-B Out.]

You have what model?  There is a RANGR 978 (UAT) model, and a RANGR 1090 (Mode S) model.  I cannot find any mention of Anon Mode for the RANGR 1090.  

And this is from FreeFlight's website (https://www.freeflightsystems.com/blo...-created-equal/): "One of the major differences between the two options is that 978 UAT offers a private operating mode, while the 1090 transponder based solution offers no such protection. This is due to the fact that 978 UAT is a modern, digital datalink, whereas the 1090 transponder based system is, like all transponders, a good old fashioned AM radio. As such 978 UAT has substantially more flexibility. And, as mentioned above, all Mode S transponders send ICAO code and flight ID anyway – so your privacy is already gone once you have one on the aircraft."

Sorry, my mistake. I am Mode C. I don't know about flying in Class A airspace. In reality, all one needs is 978. It's more versatile anyway. Any flying out of the country I do is to The Bahamas, and they could care less. An icao flight plan is required, and you  will only need 978 to re-enter the US.