ADSB-In on the cheap!

[Rampil]

Hi All,

I've been working on the Stratux project for about three months at this point and it is
at this point beginning to stabilize into a mature system. The major revisions to the code
are slowing down as bugs are becoming scarce and important features are mostly
covered. There are some tips I will share with the SWP that may be useful:

Don't bother with the EAA or other print magazine sites. They are seriously out of date
with features and buy lists. There are new SDR (receiver) dongles and wifi chips. Some of
the old WiFi dongles previously recommended are no longer supported.

At this point do not waste money on an AHRS chip. It is an added feature which is not
yet working - the output data precesses badly. I would suggest waiting until the main band
of coders resolve the sensor fusion / integration issues, then buy the chip recommended
at that point, it may not be the RY835.

To get started, if your tablet or phone already has a GPS, there is no need to buy another
one for the Stratux. It will add soldering complexity where none may be required.

As for antennae, some of the crowd has a real fetish for different antennae. However, the
little rubber duckies that come with the SDR dongles work pretty well in the air and for
the purpose of detecting relevant traffic (as opposed to stuff 100 miles away) the default
antenna works fine. On the ground, the default antenna on my rig routinely sees 1090
traffic in the flight levels at 100 - 150 SM distance. Many users got concerned when they
did not see 978 traffic or weather from on the ground. Air to ground reception of 978
traffic is still pretty rare except around airports and you won't seen most of the 978 traffic
(uplinked) or any wx unless you are pretty much direct line-of-sight to an ADSB ground
station regardless of antenna. On the other hand, if you are putting the Stratux rig deep
inside an aluminum or carbon fiber fuselage, you may need a better antenna, most likely
an external antenna because of shielding. Moving the Stratux is a cheaper solution.

The Stratux is an electricity hog, relatively speaking. Many users have gone to bigger
batteries. Unfortunately, this doesn't usually help. The issue is that the tiny wires
(like 27 ga) in cheap, long USB cables has too much resistance and drops the voltage
too much to run the RaspPi and all the peripherals. The solution is to run power from the battery through a short, high quality cable to the Pi. A double cable is probably even
better. Recent changes to the software have reduced power consumption also.

Finally, a big issue with the system is the lack of a decent case. Some people have
designed 3D printable cases which protect the components and hide the wires,but
do nothing to cut down on the radio interference generated by the Pi, or to deal with
the heat it generates. Combined with the heat from solar infra-red on the glareshield
of a SWP in a southern state is actually enough in summer to melt the 3D printer plastic.

[rocket]

Sheesh, didnt know you guys were so hi-tech or talented!

[Rampil]

Jess trying to save the boys some bucks on the toys so ya'll can buy more AV Gas

[Jim Hann]

Sheesh, didnt know you guys were so hi-tech or talented!

Yeah, for about $150 I have better weather info available in the Pacer than I do in the A300! (Yep, that is a sad statement.)

[Chris Iriarte]

Jim,

Can you get traffic with UAT only or is that information only broadcast on 1090?

Chris

[Rampil]

The stratux can receive both 978 and 1090 if you have two SDR dongles (about $30 each).


In the US 1090 is mostly transport type aircraft and you see them whiz by in the flight levels

978 UAT has much more bandwidth and has both TIS (traffic) and FIS (weather and airspace info like TFRs, MOA
activity, etc). On the ground wit 978, you will only see downlink transmissions from the occasional UAT-Out
equipped aircraft (individual traffic targets). Once airborne a 978 receiver will see the UAT ground towers which
spew TIS when there is an ADSB-Out equipped plane around your location (about 15 SM radius), and FIS all the
time.

[Chris Iriarte]

Rampil,

Sounds good ... I should get the info I want with just the 978. Flew in and out of PHX's Class B recently and got a sore neck looking for traffic.

Chris

[Rik]

Will this work with my Nexus 7 running the Garmin software?

[Jim Hann]

Will this work with my Nexus 7 running the Garmin software?

According to some folks on the Reddit page, no. It appears (I don't have Garmin software) that the Garmin hardware performs a "handshake" before the data begins. Stratux cannot do this as far as I understand. You might check the Reddit page, I just did a quick search.

Jim

[tnowak]

Interesting. Someone is doing the same this side of the Atlantic:
http://forum.pilotaware.com/index.php

Perhaps collaboration at some stage?
TonyN