| the Latest in building a STRATUX |
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STRATUX has been an amazing project that I have been working with since about late January. Using two USB Software Defined Radio (SDR) modules, a Ublox WAAS GPS, and a Raspberry Pi, it provides for ADS-B In with TIS-B Traffic and FIS-B Weather on 978MHz. Weather and Traffic are extremely helpful with situational awareness, traffic avoidance and better cross country options with weather. For a single radio solution, you would only listen to 978MHz to get traffic and weather. Using a second radio, you can listen to the 1090ES transponders directly on 1090MHz. Since I use Avare for Android as my Electronic Flight Bag (EFB), I have an option of filtering traffic within specific altitudes above and below. Since I am mostly flying in a Cessna 172, I only look for 5000ft above and below. I don't really need to see that Airliner at 35000ft above me as it only distracts and clutters the display on the tablet. I have built 5 iterations of cases and configurations with the latest being the dual radio and GPS inside of a Hammond Manufacturing 1591HBK enclosure. It measures 6.5in x 2.8in x1in and fits a Raspberry Pi inside very snug. The only issue is that you have to remove the center mounting posts for it to fit. Otherwise, it gives plenty of room to fit two radios, the Rpi, GPS, and the adapter cables for the antennas. I use a Dremel tool and a small burring bit to open three slots in the end for airflow and I cut out a hole at the other end for a 25mm 5V fan to pull the heat out since it sits in the sun on top of the panel for the best coverage. Not to mention the Rpi 3 generates more heat as well as the two SDR modules get very hot. This latest fan that I am using moves ALOT of air. After 5 hours of running the STRATUX on battery with it sitting on a table in my back room by a window, the CPU temp never got higher than 90F. Although it is not sitting in direct sun like it would on top of the panel, this is a significant improvement in cooling. Using the Kmashi battery, my latest version lasts around 6 hours. I will say that using the NooELEC high gain antennas and the STRATUX sitting on the dashboard of my car as I drive, I can see Airline traffic around 60nm away. Flying near HSA and at about 2000ft MSL, I was able to see three 978UAT towers. The standard antennas were good for seeing traffic about 30nm away. Then again, when you are cruising around relatively low, 30nm is more than enough distance to start looking for traffic. Typically, I am looking outside specifically for when I see traffic on the tablet when it is closer to 5 miles away.
Note that the fan is attached to the lid of the enclosure. 
Cooling vents cut with a Dremel tool. 
Complete unit with battery. 
Something that I started doing was expanding the filesystem with the raspi-config command since I have been using 16G MicroSD cards. I would hate for the logs to fill up the filesystem mid flight. Here is the list of what I am using now:
Include some hardware to mount the Raspberry Pi board and you are looking at around $170 in parts for the battery powered, dual band, WAAS GPS enabled ADSB-In solution. |