FlightAware Discussions

Any idea how many 1090 verses UAT out there are?

There is a discussion at out airport as to how important adding UAT in and what percent 1090 out verses UAT out. Any reliable data or guesses out there as to the 1090 verses UAT. I saw something in 2014 it was 2/3 1090 and 13 UAT. What about 2020?

you could go to the FA adsb stats page and then look at ADS-D and then statistics. you can go down the columns and see the sites that have both 1090 and 978 and look at the ratios.

UAT installs in 2014 would have been effectively zero.

A highly unscientific count I just did now (it only covers one day, minimal data cleanup, and I filtered for only US-registered aircraft as a proxy for “flying within the US”, since a global comparison for UAT would be mostly meaningless):

2104 UAT-out-equipped aircraft
21484 ADS-B-out-equipped aircraft

So call it 10% UAT?

Take this with a large grain of salt, there are potentially large systematic errors in that measurement, and UAT sees large day to day variations due to day of the week and weather. It’s also measuring “What proportion of aircraft that flew on that day and that FA saw are UAT equipped?” not “What proportion of aircraft overall are equipped”.

Another issue would be aircraft that have both UAT-out and ADSB-out. Some may have both for better visibility in high traffic areas. I like the notion of see and be seen, so having both would appeal to me.

Obj very helpful. Thanks for the efforts greatly appreciated. Another factor is the greater coverage of 1090. As an example at my airport we do not have UAT coverage so I would not be picked up. Never the less, even if it doubled the UAT still very small percentage. IF I would have done better homework before buying my 1090/UAT in, UAT out, I probably would have chosen differently. I was led to believe UAT was the standard for GA aircraft. My bad. FlightAware has been very helpful in understanding this situation. I am going to do some research in the GA and LSA and report back.

If you have a location at your airport where you’d be interested in setting up a 978 FlightFeeder I’d love to send you one. If that’s the case please message me.

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Try my statistics for the 1090 MHz receiver and a separate 978 MHz receiver at the same location.

Yesterday at 23:59:59 zulu it was 2231 different 1090 MHz ADS-B out aircraft versus 117 different 978 MHz ADS-B out aircraft.

5% of ADS-B transmissions received are 978 MHz while 95% are 1090 MHz.

Why would any aircraft owner think that a 978 MHz UAT will be sufficient coverage?

that in turn leads to questions about your coverage. You can likely see 1090 much further out than 978 (which fly lower). For me, I have about 5-10% UAT count compared to 1090ES. But I can see 1090 all the way from Bakersfield to the Oregon border (a 10-ish hour drive by car). UAT I can see from Sacramento down to San Jose or so (about a two hour drive by car). That affects the fairness of the comparison

UAT on 978Mhz was designed to be a cheaper alternative to the congested 1090Mhz. Installations are 1/3rd to a 1/5th the cost of ADS-B. It was meant to ease the 2020 ADS-B mandate.

The carrot is that UAT also provides near real-time weather, TIS-B, ADS-R and FIS-B if ADS-B UAT IN is provided by the equipment. This is often at an additional cost. ADS-B 1090Mhz does not provide weather. You can get cheap UAT receivers. You can even build them from RPIs (stratux.me), however, some services require that a nearby aircraft is transmitting UAT 978Mhz.

UAT 978Mhz is only used in the US. If you want to fly Internationally then you will also need ADS-B 1090Mhz. The same if you want to fly about FL240.

The ground range is not that important for traffic avoidance(Arguably the primary reason for a transponder). It is needed for flight monitoring so they have installed a large amount of ground stations around the country and even on Oil rigs in the Gulf of Mexico to assist with tracking of oil rig helos.

Yes my goal is to get CXP, TVL, TRK, SPZ, MEV, 043 and perhaps north eastern Nevada all set up with UAT. Specifically so we can expand UAT tracking with FlightAware and expand our understanding of all air traffic in this region. It appears RNO, an international airport does not have UAT receivers which is hard to believe so I am pursuing this. My home airport CXP is getting a new box which should get UAT as we speak. So e mail contact would be best contact at Paul@SportAviationCenter.com
So I need to get these two airports (CXP, RNO) sorted out first. But if you could e mail me or call 775 772 8232 we can get a plan and make sure I understand the 978 FlightFeeder.

you ask “Why would any aircraft owner think that a 978 MHz UAT will be sufficient coverage?”

Because we were led to believe that UAT 978 was a good option. Even now if you research 1090 verses 978 the better coverage of 1090 is not really promoted as a reason for going to 1090. I did pretty good research up front and ended up with “978 out” for both my aircraft (I get 1090 and 978 “in” on my cockpit screen so I at least see all the other aircraft who have 1090 and 978. To be honest I am irritated that after installing 978 MHz UAT for both my aircraft to find out through actual flying experience that UAT has so much less coverage. It is obvious to me now, and most here really into it, but it was not at the time.

UAT 978Mhz and ADS-B 1090Mhz FAA ground coverage should be the same. I believe that each ground station receives and transmits on both frequencies.
Flightaware receiver coverage is going to be much lower. We only got decent UAT 978Mhz receiver software recently. Not many people will have gone to the trouble of installing it, especially if they are interested in commercial traffic.
Air coverage within the same frequency should be more than enough for see and avoid(as I stated above). ADS-R/TIS-B, if in range of a ground station, will provide everyone UAT, ADS-B and some radar traffic. There is definitely a possibility that you won’t see all aircraft if not in the range of a ground station. This is also the case for aircraft that don’t have their transponder turned on (It is not required everywhere in the US or in many other countries).
978-Out, in areas without ground coverage, could mean that 1090-in/out aircraft won’t “see” you. It is an annoying part of the dual frequency system.