DIY ADS-B In & FREE Flight Nav App

[RudiGreyling]

UPDATE [10 April 2025]: I changed the topic to include the FREE Nav App and changed some of the pictures in the first post
UPDATE [17 April 2025]: Added pictures of the Version 2 Test Prototype based on a smaller cheaper RaspBerry Pi Zero 2W
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STRATUX: www.stratux.me
Stratux is free software that enables DIY and low cost ADS-B receivers for pilots. It’s easy to build an ADS-B receiver from the parts list, or there are many inexpensive pre-built options available. Stratux-based ADS-B receivers are the only full-featured receivers on the market that are compatible with every major EFB and the Open Glider Network.

ENROUTE FLIGHT NAVIGATION APP: https://akaflieg-freiburg.github.io/enroute/
"Enroute Flight Navigation is an award-winning flight navigation app for Android and other devices. Designed to be simple, functional and elegant, it takes the stress out of your next flight. The program is free. It has been written by flight enthusiasts, as a project of Akaflieg Freiburg, a flight club based in Freiburg, Germany."

FreeCAD: https://www.freecad.org/
"FreeCAD is a free and open-source parametric 3D modeling software primarily designed for mechanical engineering and product design. It's also suitable for architecture, BIM, and other engineering specialties. FreeCAD allows users to create 3D models, modify them based on their history, and generate production-ready drawings."
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I recently discovered an open-source project called Stratux, (www.stratux.me) which caught my attention due to its community-driven approach, years of refinement, and affordable hardware. With a bit of electronics and computing know-how, you can build your own system—and I did! It works exceptionally well.

This setup provides ADS-B In functionality only, allowing you to view other ADS-B-equipped aircraft, though they won't be able to see you. As more airplanes adopt ADS-B Out, having this feature integrated with a moving map on your tablet or phone significantly enhances situational awareness, displaying nearby traffic directly on your map.

At its core, the system uses a microcomputer (Raspberry Pi) combined with a Software-Defined Radio (SDR) receiver, which is tuned to the ADS-B frequency. It picks up and displays local ADS-B traffic. Connecting to it via Wi-Fi enables you to use either its native app or your preferred moving map software (e.g., Airnav Pro, OzRunways, Enroute Flight Navigator). Personally, I stick to Enroute Flight Navigator app since it is also free, cumminuty driven too.

Here's a glimpse of my initial build—Version 1.0, featuring a Raspberry Pi 4. For a sense of scale, I placed a credit card next to it. The device is slightly larger than a cigarette pack (approximately 1.5 times the size). A cooling fan is absolutely necessary, as the device generates significant heat when placed on the glare shield.

Has anyone else experimented with this setup?
I'm already brainstorming ways to make it smaller and more cost-effective.

Here is my initial V1.0 Rudi's Stratux test bed.

rudi_stratux_v1.0.jpg

UPDATE [17 April 2025]: Here is a comparitive photo of Version 2 Test Prototype (on the left) based on a smaller cheaper RaspBerry Pi Zero 2W, it is discussed later in the forum posts...

pizero2.jpg

TESTING:
Here is some updated split screen shots from my Ipad, testing from home base.
On the LEFT is the Free Enroute Flight Navigation (EFN) App and on the RIGHT is the STRATUX native website/app.

ADS-B Traffic:
One the Left you can see traffic aircraft ZS-CCT (2,254) ft above my position flying to the west (It is ADS-B traffic so we can see the position height and direction), The STRATUX native app on the right shows traffic RADAR SCREEN and it can voice announce traffic. You can change the range of the radar and the altitude warning around you, to suite your needs

stratux_6_radar.jpg

MODE-S Traffic without ADS-B position:
The next screen on the LEFT the EFN shows a green circle around my position, since the STRATUX radio has picked up ZS-AMK with a Mode S transponder, it knows the altitude but not position, so it estimates the range and draws a danger circle around you. The STRATUX screen on the right confirms it is BASIC Mode S trafic

stratux_6_modeS.jpg

Here are some other usefull STRATUX Screens, like GPS and Status etc.

[Dobbs]

Would this be similar to the SafeSky app, albeit with SafeSky app requiring cell coverage?

[rainier]

We have been using and supporting Stratux for our EFIS systems for more than a decade.
It works well and is affordable.
Note that here you only use the 1090ES in. 978Mhz UAT does not exist on our continent.

Stratux works with anything that supports GDL90 protocol either via wired RS232 or Wifi (same data as on the RS232 feed).

[RudiGreyling]

Would this be similar to the SafeSky app, albeit with SafeSky app requiring cell coverage?

Hi Dobbs, This DIY Stratux Project is a RADIO receiving all the Mode S transponder signals and ADS B radio signals in your area and display them on a phone or tablet, No internet Required!

I'm not sure about SafeSky, I haven't used it but from their website (https://www.safesky.app/) it looks you need an internet connection as first option and that limits you in the bundu's.

Safesky website says they also have a receiver option available by a 3rd party (AERO Tracker) (this would be similar to this DIY Stratux project) but their Aero Tracker device costs 575 Euros! Ouch that is expensive (+/-R12,500) ...I will post my current project costs later, mine was much MUCH cheaper (and I am already thinking of ways to make it smaller and cheaper as a challenge. I have no commercial interest here, just the challenge and sharing good stuff with like minded aviators)

It looks like safesky also has a monthly subscription option for certain tiers, the Stratux project has no subscription.

I will go play with Safesky later the weekend and get a better opinion, and report back....

[RudiGreyling]

We have been using and supporting Stratux for our EFIS systems for more than a decade.
It works well and is affordable.
Note that here you only use the 1090ES in. 978Mhz UAT does not exist on our continent.

Stratux works with anything that supports GDL90 protocol either via wired RS232 or Wifi (same data as on the RS232 feed).

Wow Renier, I only found out about Stratux 2 weeks ago, and were surprised they were running for almost a decade, so it is well supported and sorted out for a community project.

Yes, I am currently running 2 receiver radios in my trial test setup, but it is a waste: One for 1090Mhz (official South Africa ADS-B) and one for 868Mhz (lets call 868Mhz the unofficial amateur band that various organisations could use, and potentially later on ADS-L Europe that might come here). YES the 868Mhz radio is a waste currently, I have yet to see any traffic on 868Mhz in my testing. So in the next iteration of my DIY I am planning to only use 1 Radio Receiver monitoring 1090Mhz, making the solution box smaller, cheaper and more efficient.

Kind Regards
Rudi

[rainier]

I actually designed a prototype ADS-B (978Mhz UAT) and 1090Mhz ES receiver some time ago (includes RS232 and Wifi). Works well but have never put it into production. Just too busy with too many projects and too little time...

As you probably know UAT requires ground stations to operate - unlike 1090ES it is not unsolicited transmissions. The ground station starts an interval consisting of a period where it transmits things like weather radar images, Notams etc and then a second period starts where aircraft can transmit their data - during this interval aircraft choose a random time slot before the whole thing repeats.
No ground station - no transmission from the aircraft fitted with a UAT transponder (it may not see a ground station for whatever reason and any random transmission would then potentially interfere with the ground stations transmissions so other aircraft might get garbled data).

1090ES is better in this regard as it does not require a ground station or even secondary radar to work - you switch the transponder on and it tells everybody what you are busy doing and where you are. Except on the ground (for most transponders anyway). Usually on the ground you are silent unless your transponder supports ground mode. Ground mode is similar but data is structured different allowing for higher position resolution so it becomes more useful to locate aircraft and other items like tugs and vehicles accurately at an airport.

[Thermalator]

some are confusing different things:

• 978 mhz UAT = FAA licensed DATA network for ADSB traffic AND weather and weather radar and Arinc ++ >1w TX, US only
• 868 mhz = FRS free radio for any app non aviation 0.25w max TX, FLARM (gliders)and FANET(drones and paragliders)

[RudiGreyling]

Would this be similar to the SafeSky app, albeit with SafeSky app requiring cell coverage?

Hi Dobbs, This DIY Stratux Project is a RADIO receiving all the Mode S transponder signals and ADS B radio signals in your area and display them on a phone or tablet, No internet Required!

I'm not sure about SafeSky, I haven't used it but from their website (https://www.safesky.app/) it looks you need an internet connection as first option and that limits you in the bundu's.

Safesky website says they also have a receiver option available by a 3rd party (AERO Tracker) (this would be similar to this DIY Stratux project) but their Aero Tracker device costs 575 Euros! Ouch that is expensive (+/-R12,500) ...I will post my current project costs later, mine was much MUCH cheaper (and I am already thinking of ways to make it smaller and cheaper as a challenge. I have no commercial interest here, just the challenge and sharing good stuff with like minded aviators)

It looks like safesky also has a monthly subscription option for certain tiers, the Stratux project has no subscription.

I will go play with Safesky later the weekend and get a better opinion, and report back....

Hey Dobbs, go read Thermalator's post in link. Safesky looks to be an Internet Aggregator, but you can connect an external radio device too, at hefty price/subscription fee: viewtopic.php?t=270982

[RudiGreyling]

some are confusing different things:

• 978 mhz UAT = FAA licensed DATA network for ADSB traffic AND weather and weather radar and Arinc ++ >1w TX, US only
• 868 mhz = FRS free radio for any app non aviation 0.25w max TX, FLARM (gliders)and FANET(drones and paragliders)

Yes ThanX! and just for completeness 1090 Mhz = Mode S transponders and ADS-B fequency in South Africa. The one I am most concern about.

[RudiGreyling]

OK here is the cost if you DIY and source the parts yourself: Call it +/-R2,000
1 x Raspberry Pi 3B = R760 (www.pishop.co.za) [I used a Pi4 which is an overkill, Pi3B is perfect for plug and play]
1 x Black ABS case and Fan = R70 (www.pishop.co.za)
1 x Radio Nooelec NESDR Nano 3 = ($42 www.nooelec.com) (You only need 1 Radio for South Africa.)
1 x 1090MHz ADS-B Antenna SMA = ($8 www.nooelec.com)
1 x USB GPS (G-Mouse or VK-162 or equivalent) = (R135 www.alieexpress.com)
PS: If you know of local or cheaper quality altnartive parts for the international parts listed above please let everyone know below.

Or you can go to stratux.me website use their links to AMAZON.COM and buy all from there, they have most of the components altough a little bit expensive, but then you can do it for under R3,000.

Here is my DIY V1.0 but you really only need 1 Radio and Antenna for South Africa. I am already thinking about a DIY V2.0 smaller, cheaper, and only 1 radio, more on that later....

rudi_stratux_v1.0_open.jpg

[RudiGreyling]

Ok here is an update for my DIY, lets call it prototype version 2.

The Pi Zero 2W is also using a 64bit processor but much cheaper, R320 vs R760 and also much smaller footprint, and uses less power compared to a Pi 3B. Only problem is it does not have a full size USB ports, so you need to solder a bit. The benefit is you can also use better smaller more readily available GPS's to connect/solder directly creating an even smaller foortprint. I used a nano M10 ublox I grabbed from one my radio control drones .

Below you can see the size comparison. Prototype Versions 2 on Left and Version 1 on the right.

pizero1.jpg

Now all I have to do is to design a 3D case and 3D print it to fit Versions 2, and go test it.....stand by!

[V5 - LEO]

......Rudi, jy is 'n baie handige man

[Whirly]

......Rudi, jy is 'n baie handige man

Wat dié manne kan doen, rainier ook, en nog 'n hele paar ander, verstom my!

Whirly.

[rainier]

This is the little prototype ADS-B receiver I designed a few years ago.
Signal processing completely digital using a cheap satellite receiver chip (somewhat misused).
Used two processors and signal chains - one for 978Mhz UAT and the other for 1090Mhz ES. This way the system could be built with just the parts for the 1090ES which is more common and saving costs. Used the same CPU I use for the N16 NAV radio and T16 transponder for stock keeping purposes but these would be replaced by much smaller chips that would be less costly in a production version.
Bottom right is a u-blox wifi module - used this one even though its a bit more costly as it has ICASA approval so I don't have to mess with that (ICASA is impossible to deal with).

[V5 - LEO]

......Rudi, jy is 'n baie handige man

Wat dié manne kan doen, rainier ook, en nog 'n hele paar ander, verstom my!

Whirly.

......wil nie eers praat oor die "duitser" nie - Rainier doen en praat 'n taal wat net 'n paar fundis verstaan en antwoord