1090 vs 978 mhz...does the Pi software get them both?

USA ADS-B uses two frequencies; 1090 for some and 978 for others.

I see the dump1090 streaming from my station but that is it as far as I can tell.

Any comments?

No, piaware doesn’t directly support 978MHz. There isn’t much downlink traffic on 978.

dump978 will receive it, and you can in theory feed that on to piaware, but you’ll need to do the plumbing yourself (and you’ll need a second dongle)

You are right, there is not much 978 MHz traffic picked by my receiver in Toronto, although my receiver’s range extends nearly 250 nautical miles inside USA.

I have not installed dump978 or done any “plumbing” :slight_smile: on my RasPi or PiAware to try UAT 978 MHz. Rather I found an easy shortcut. I have installed on my Android phone, an App “ADSB Receiver” by HIZ LLC (shown as Avare ADSB after installation). This App has option to use either 1090 MHz ES or 978 MHz UAT. I used an OTG USB cable to connect my DVB-T USB Dongle to the phone.

Please see screenshots of my Android Phone below.


**Hardware Setup **
(Photo was taken when Flightaware’s FlightFeeder for Andriod was running)

Thanks all…I just found more here: ads-b-flight-tracking-f21/978-mhz-uat-in-the-us-t18256-50.html

There is also WX data in the UAT 978 data right? I think that is the primary advantage for GA users…

UAT have two main components - uplink and downlink. The downlink provides positional messages from the airplanes and dump978 take a good care of decoding those messages. The uplink have a magnitude of information (retransmission of the 1090ES position messages, NOTAMs, METARs, TAFs, weather maps etc), but you must have a line-of-sight to the ADS-R antennas in order to get that data. dump978 can decode the retransmitted positional data and some of the other messages, but currently does not decode multi segment messages such as long METARs or NOTAMs.

I have come across an Android App “ADS-B on Android”, which has METARS & NOTAM

https://farm6.staticflickr.com/5807/23057546713_bb27d879f9_n.jpg . https://farm6.staticflickr.com/5642/23057529923_df64c399a4_n.jpg . https://farm6.staticflickr.com/5637/22757134337_acbbec4283_n.jpg


There is an improved image for using dump 1090ES+978 on GDL90 protocol to make it work with various GA Flight Apps viz. ForeFlight,etc. Its being developed as an open source product to compete with commercial ADS-B units like Stratus. It uses an improved version of dump978 and definitely shows performance and accuracy. I have however been manage to pipe the output to my main PiAware device. Most GA traffic in my area gets rebroadcasted on 1090 and you have to be close to ground station to receive decent amount of 978 traffic. I generally see 30-40 aircraft from my office while it drastically improves to 70-100 aircrafts if I get close to the airport.

Give it a shot, its quite impressive.


Connect to on the device. It’s a websocket that streams 1090MHz traffic and 978MHz traffic also - in JSON format.

I built a Stratux with AHRS, GPS, 1090 & 978UAT
Works well.

I live a little over mile away from the FAA ground transmitter near Rhome Meadows airport.
I would think adding 978 UAT in, would allow for improved performance with MLAT processing since any rebroadcast of traffic from the ground would include big iron and small GA. Since I get the ground transmitter it would make sense to add it piaware ?

UAT has position data already so MLAT on 978mhz doesn’t make much sense. For rebroadcasts it would just find the ground station anyway :wink: It doesn’t help for synchronisation for 1090 mlat as the same dongle needs to hear both the sync message and the message to multilaterate.

The TIS-B broadcasts of radar tracks are of limited use to FA as most don’t carry an ICAO address or callsign so you can’t match them up to anything else. Rebroadcasts of 1090 data are probably bring heard directly already.

In theory I think the UAT downlink info should be being rebroadcast on 1090mhz anyway, if you can see that ground station…

There are a few edge cases where it might help but given that it needs a second dongle really it’s a bit marginal.