(Update: It was made known to me that it might not be clear what a Stratux is. It’s a device that among other things the ADS-B system provides, allows you to receive weather from ground based stations and traffic from both the ground based stations and other aircraft around you with ADS-B out. It was created by Christopher Young along with a team of volunteers who put the plans for making your own out on the internet. Making your own cost less than $200 compared to the $600 for commercial systems. Read more about it at the end of my previous post or here at Garmins website. )

The past few weeks following my previous post have been a little hectic. We’re trying to wrap up the maintenance on our fleet of airplanes and we’re running a little short on time. One of the more exciting things I’ve gotten to do however was flight test the Stratux … And I have to say I was pretty impressed. On takeoff, climbing through 600 feet I already had 2 towers. Approaching our normal cruise altitude of 5,500 I had a maximum of 8 towers. This whole time I had an up to date weather picture in a large circle around my current position. In addition to that traffic was everywhere, most too high or too far away to identify visually but in the least they were showing up. I was pretty happy … I managed to put it together and nothing broke/got set on fire/summoned unholy zombies. Not only that, but if this continued in the way it was working now then the days of landing just to find out what the weather was up ahead were over.

Stock antenna left, Pair of Digikey 916 Mhz antenna right

I spend the next few days and weeks tweaking settings and spending a lot of time on the Stratux Reddit page (fascinating place if you’re interested in building one of these … I have learned so much in my brief time there). Eventually I came across some Digikey 916 Mhz antennas that were supposed to be better and more compact.
I took them flying … but they were disappointing. Compared to the stock TV style antennas they weren’t doing as well. The stock antennas were picking up far more traffic messages compared to the higher quality Digikey ones. Confused I ended the flight and went back to the drawing board. My follow up research showed that it was perhaps the placement. In my first flight test with the stock antennas, they were located pretty far forward on the dash of the Piper Cherokee I was flying. For the digikey antennas due to the way they were mounted, they were far taller and sat further back. So a large part of it might have been the fact there was more airplane between the antenna and the ground stations. Additionally turns out having two antennas within about a 1/2″ of each other can have adverse effects. So I’ll need to do a more controlled comparison. I’ve also purchased some GPS antennas that i’m going to cut and turn into a half wave vertical antenna. I’ll drive out to the nearest ADS-B ground station and do some testing there.

Some of the modification work already done.

The other thing I’ve been working on was providing a case for it. Previously I’d been using a case that only enclosed the Pi, which led to several of the components just sticking out. I figured I could do better. The Stratux community has quite a few talented creators who have whipped up 3D printed cases for their devices. One of the more popular ones is created by a user who goes by the handle of Helno. He put together a truly elegant case that was perfect for what I needed. Shortly after I learned that 3D printing was expensive and that the cheapest I’d get the case printed for was about $30. That may not be a lot but the idea I pitched to my boss was that it was a cheap way to get airborne weather … and didn’t necessarily want to add on additional cost. So I started looking at other options. What I eventually settled on was a Radioshack 6x3x2 plastic enclosure. $5. It obviously required me to do more work but I didn’t really mind. The modifications I had to make to make the enclosure useful include:

• Drilling a hole for a power jack
• Grinding down the strengthening ribs on the walls to get more clearance (Strength loss was deemed to be irrelevant.
• Grinding down the PCB supports on the inside (I would be installing my own standoffs)
• Grinding down the bottom part of the enclosure lid mount supports (Mostly to get the power jack to fit and to provide more clearance for the SDR’s

To make this work I had to add on additional items. I added some fans for cooling, a power switch, a power jack, UBEC (Universal Battery Eliminator circuit … Simply put a power regulator), and a USB micro breakout board for supplying the Pi with power.

Moar Parts!!!

Even with all those parts the final cost for a Dual Band Stratux is still under $200 … Far less than the $600 asking price for the commercially built Stratus. I’ll need to also cut venting holes in the box for the Stratux but i’ll outline those in a later post.

So far everything is going great and I’ll write up another post soon on the additional case mods and more pictures of the process (I haven’t been doing a particularly good job of documenting photos).