Should i buy a second sdr?


So I have my new antenna wired up, and I have piaware downloaded to my SD card. I’m about to order a raspberry pi 3. But I have one question. Should I order 2 SDR’s? I know piaware natively runs dump 1090, but I was wondering about UAT. Can I pick it up with the second SDR without “nasa level” ssh programming on my part? Will Piaware natively run UAT if I have a 2nd SDR installed in my raspberry Pi?


If you use Joe’s scripts, it is very easy to setup UAT 978


I live in NYC and only see about 1 aircraft per day. There just doesn’t seem to be much UAT traffic in NYC at the moment.


I don’t see why dump 978 can’t be native to piaware. Other ads-b type programs such as Stratux, automatically do this. 1 sdr gets 1090mhz and the other gets 978mhz. Piaware should just be natively designed that if you only have one SDR , then it gets 1090. If you have 2 SDR’s , then you get both.

I would think that flight aware would want the free aircraft information, even if it is one plane a day. Honestly, I hate programming and trying to install extra scripts on the pi. I’m not much of a computer guy, more into the radio and aviation side of things. So I don’t really have the know how to be getting on github and going crazy installing all kinds of stuff.

In the long run, it’s flight aware that is losing out by not including this in the piaware software. I have the hardware required to pipe this information to flight aware, but I just don’t have the software or computer know how to set it up. Oh well, looks like I’ll have an extra SDR and antenna sitting in my closet.


UAT 978 is only used in the U.S.A.
It is not generally used by commercial aircraft(although it can be if they don’t go into Class A airspace).
It is mostly used by G.A. aircraft.

In NYC I see 3000-4000 aircraft per day(I am terrain shielded for over 90 degrees so should see more).
I only see one or two UAT aircraft per day.


It’s somewhere on the todo list, but there are many higher priority items ahead of it. Adding UAT does not collect much more data and it does add a lot of complexity to a piaware setup, e.g. you need a way to say that you want one particular dongle to be used for UAT, and dump978 needs a bunch of work to be productionized, and we’d need to work out an equivalent to faup1090 to handle the 978 data. It would be nice to have but I think you underestimate the work needed and overestimate the benefit.


I believe when the FAA mandate deadline hits in 2020, the value of UAT will greatly increase for flight tracking. All general aviation aircraft will be required to have ADS-B out while flying in controlled airspace. Most general aviation pilots are going with UAT , due to it’s significantly less cost of installation. Along with UAT carrying weather/notam info to the cockpit, while 1090 does not.


In practice, though, I have not heard of a dump978 install that hears more than a handful of UAT-equipped aircraft a day.


I suspect that GA will convert to UAT at the last possible moment.

Maybe petition the FAA that they need more time in late 2019 :slight_smile:

Like others I only saw a few aircraft each day. I did see some jets doing UAT above 18,000 feet which was strange.

Hardly any data flows from the ground sites. I can hear two of them, but they never transmit unless an aircraft is withing a few miles of traffic.


That’s because most general aviation aircraft are not ADS-B out equipped yet. However, by the time the FAA’s 2020 mandate hits, that will change. Somewhere to the tune of approximately 225,000 aircraft. That’s an extra 225,000 ADS – B out transmitters in the air. Most of them will be utiliting UAT out, due to costs.

The main reason you were not seeing UAT right now, is because they are not there. By 2020, totally different ball game.


If “not a lot before 2020”, that gives “obj” 2.5 years to get UAT into Piaware (start of 2019 :wink: ).

No need to worry about 2nd SDR for now and by then we’ll be on Pi4/Pi5?

If you do need it now the automated script mentioned in the 2nd post will get it installed by following some simple instructions.


Because it also has a Mode C or S transponder. Not uncommon.

I get a handful of UAT traffic per day and my UAT antenna isn’t high. It’s harder to pickup UAT traffic because it’s typically flying lower then much of the Mode S traffic. A local flight school likes the coverage.

There will be a lot of UAT traffic soon unless you live in a desert.