Dump978 and multiple feeds questions and more....

FlightAware ADS-B Flight Tracking
1

Hi,

My first time to post. I am a new feeder, here in the Asheville, NC area. Started out with FR24, but after starting to use VRS, I realized I had no MLAT data fed back, so I dumped them. I only do this as a hobby anyway.

A couple of questions and observations. So I am a pilot, used to fly SAR, and recently looked at the pros and cons regarding non encrypted data, Mode-S, ADS-B and MLAT. Had an interesting discussion with another pilot I used to work with who insisted, military flights are blocked. Well, only partially as I expect most of you know. Feed the decoded data to VRS, and while there might not be a “Call Sign”, they sure come up as to who they are registered to (USAF for example) in VRS. That was interesting.

On to my next objective and questions. I have about 60 percent coverage because my setup, which includes an amplifier, filter and Flightware 1090 antenna are mounted on a post on my balcony. I am lucky in that I have an almost direct line of sight with AVL. I’m considering building another RPi, if my neighbor across the breezeway will let me put it and an antenna there, and merging the feeds. My WIFI is strong enough to make the connection. I have an amplified WIFI network. I know it can be done, was wondering if anyone has on the forum, and any advise? Also, I downloaded dump978 and installed it and tested it on a second dongle I have (from my old Stratux) and am thinking about merging that data (through a software conversion to conform to dump1090 requirements) and sending it all up to Flightaware. There are quite a lot of 978 ADS-B Out small aircraft here in the USA. I know I need to change the serial number on the second RTL, in that I’ll be running both off the same primary RPi. The one across the breezeway would be a 1090 only setup and only a feeder to the primary RPi running Piaware. Oh, I’m also using the Dump1090 Mutable software and the external web server, not the built in one from dump. So, has anyone tried merging the 978 data? I have already installed it, it works, recognizes the RTL and decodes the data.

Only one problem. I’m going to have to use a powered USB hub to attach to the primary RPi, for both power and that I can’t fit two dongles next to each other. Anyone using a powered USB hub? Problems?

That’s about it. Thoughts, suggestions, ideas are welcome and appreciated.

jack

2

The main gotcha here is that mlat will not work if you give piaware a merged feed. You will need to run two separate piawares each processing unmerged data from a single receiver, and merge the feeds separately for your own use (e.g. in VRS).

For UAT data that’s not so critical as uat2esnt won’t include timing info so it should not confuse mlat.

3

Thanks for the reply. It’s going to be interesting to see how much 978 traffic I actually get. I’ll report back…

jack

4

I live in NYC and get quite a variation in traffic.

This is my UAT only setup
flightaware.com/adsb/stats/user/ … tats-20974
I can go from 30 ADS-B aircraft per day(bad weather) to 450.
I can go from 30 ADS-R/TIS-B per day aircraft to 2000.

The range will be significantly less as most UAT aircraft fly below FL180.

If you need a filter, they can be hard to find. I currently have the hab/nevis filter/amp (with the FA filter in front of it) but have custom Cavity filters on order(They sent me the wrong type and I had to wait for Lunar New Year to finish before they started production again). A filter is a must in electrically noisy locations. I get 2 ADS-B aircraft without one and 200+ with one. I am currently using the Old FA Dual band antenna. I have a DPD antenna and am just waiting for the weather to warm up before I replace it.

PM if you have any questions.

5

Thanks johnhawks230. I will look at your setup. Appreciate the reply. I’ll PM if questions. have a great day.

6

I would be interested in a configuration that uses the Stratux hardware and what software you need and how configured for flightaware?

I have both SDLs and 1090 and 978 antennas. How do you make piaware work with it?

7

It’s still a work in progress, but here is the flow so far.
Download and install the source for the RTL-SSR, compile and install. I’ll look for the guide.
Download and install Dump978
You will probably need a powered USB port that Debian Linux recognizes. Not enough space usually for two dongles on an RPi.
On the source page for dump978 is the directions for piping the raw output for dump978 data to a dump1090 format.
Make sure your converted data is available on an open input port on dump1090.
Configure dump1099 to receive data on that port. It will not be mlat, so no issues with time differential since it’s not mlat and both dump1090 and dump978 are running on the same RPi.

The data should merge with the other RTL info and be available for piaware to upload to Flightaware servers.

You will see on the dump978 page how to create a filter to also filter out TIS-b weather and only use position data.

I suggest you first try getting the dongle running, test it first, then dump978 and watch for raw data before going further. I’ve flown with my 978 Stratux and know from experience the limitations receiving data on the ground and distance. Depending on your location, it may not be worth the effort, other then a project.

Because I don’t want to take my piaware and dump1090 offline for an extended period tight now, and have a lousy 978 antenna, I picked up no 978 traffic with it running for several hours. I’m pretty sure all my configurations and such are right. There may just not be much 978 traffic, especially now that the price has come down for aircraft dual 978/1090 Out systems.