Building an Inexpensive ADS-B Receiving and Sharing Station
ADS-B Aircraft Monitoring can be a fascinating hobby, allowing you to view live tracks of some nearby aircraft within a 100 miles or more in your area. Some hobbyist also like to share their data with networks that provide this information to the general public. ADS-B monitoring can be an expensive hobby with ADS-B receivers alone going in the $200 to $800 range plus the cost of a computer system to process, display aircraft positions, and possibly share the data. Thanks to recent advances is using certain inexpensive Digital Video Broadcast – Terrestrial (DVB-T) dongles as Software Defined Radios, it is now possible to create very inexpensive versions of ADS-B receivers and sharing systems. This article will show you how you can create your own complete ADS-B receiving and sharing station for less than $200. This is done using some inexpensive off the shelf computer hardware and a RTL2832U DVB-T stick. The price of this project can vary greatly depending on what you may already have on hand, what hardware options you choose, and where you shop for parts. This article will try to keep the price around $200 or less. You don’t have to be a computer expert to build this system, but a passing knowledge would not hurt. It can look a little difficult, but in practice, you can have the system up in running in a few hours. You may even want to get one of your Ham buddies to help out. Most of what you need to know about setting up an ADS-B receiving station already exists on the Ham Radio Web site. We are just going to put it together in one cohesive project. Just to make it easier, I will refer to the system as the RTL-ADSB1.
The RTL2832U DVB-T Stick
First thing you are going to need for the RTL-ADSB1 receiver is a RTL2832U DVB-T stick. You can’t just use any old DVB-T stick. You will need one with either a RLT2832 / E4000 chipset or a RTL2832U / R820T chipset. Testing done by Ham Radio Science has shown that the RTL2832U / R820T is a far better performer than the RTL2832U / E4000. I would highly recommend that you use the R820T DVB-T stick for this project. The RTL2832U DVB-T sticks can usually be found for less than $25 dollars. The included whip antenna will work pretty well indoors snagging ADS-B signals up to 75 miles away. Of course the range will depend on factors like your location, aircraft in the area, RFI interference, etc. You can also use an outside mounted ADS-B antenna, that will greatly extend your range. You can either purchase a commercial antenna or make one. If you decide you will use an external antenna, keep in mind you will have to purchase an adapter to covert from a PAL or MCX connection, since these are the connectors the RTL2832U sticks use. If you need to purchase a RTL2832U stick, I would highly recommend ordering one from NooElec. NooElec is one of the few vendors that is very knowledgeable about these DVB-T sticks has began to develop add on products for the RTL 2832U SDRs such as the excellent Ham It Up converter that was reviewed here in an earlier article.
RTL-2832U Stick Source (either one will work fine, but the RTL2832U / R820T will do a much better job if your going to only use the included whip)
DVB-T USB Receiver & Low-Cost Software Defined Radio (SDR) – Realtek RTL2832U + Elonics FC0013-Based
Computer Hardware for the Receiver
The heart of the RTL-ADSB1 is of course a computer system that is used to decode the ADS-B signals that the RTL2832U receives. Once decoded the tracking information can then be displayed or shared. The goal of this project was to come up with a very inexpensive dedicated computer that could handle these tasks using off the shelf parts. Of course, you can use an existing computer for this project if you wish. You will need minimally something with a dual core processors running about 1.2 GHz or above. The other consideration of using an existing computer is that the RTL-ADSB1 needs Linux as an operating system. Understandably, some users may not want to put Linux on their only computer. If you are going to be sharing ADS-B data, you would probably prefer a dedicated system anyway.
The design goals of the RTL-ADSB1 computer included:
- Low Cost
- Low Power Consumption, since if you are sharing data you would like to run the system 24/7
- Small size about the same size of a ham radio receiver
- Low noise
- CPU powerful enough to decode ADS-B signal using the gr-air-modes decoding software.
- Features such as USB 3.0, SATA3, were not necessary to this project and keeps the cost down.
You might wonder why a cheap single board computer like the Raspberry Pi was not chosen for this product? The answer is that the Raspberry Pi CPU is just not powerful enough to handle the processing needs of the current state of ADS-B decoding using a RTL2832U stick. Besides, when you consider that the total cost of a Raspberry Pi Model B with a case, power supply, SD card, and shipping, will run about $80 -$100.Motherboard
Since the popularity of the Raspberry Pi has been pretty high due to their small size and modest cost, some other cpu / motherboard options are frequently overlooked. There are several cpu / motherboard combinations available in the Mini ITX form factor. Although not nearly as small as the Raspberry Pi, the Mini ITX still offers a fairly compact size (usually about “6.7 x ” 6.7) with much more available CPU power for not much more than the cost of a Raspberry Pi. The newer Mini ITX motherboard / cpu combinations also offer low power draw of approximately 25 watts or less. Another big advantage of these boards is that they come pretty complete. The CPU is preinstalled as well as the graphics system. All you need to add is a case with power supply, a stick of 1033 memory, and a storage device to complete the system. This makes the computer system very easy to build, even for someone who has never built a system. You don’t have to install the CPU or a graphics card, just drop it into a case, connect the power, make the case connections, pop in a stick of memory, add your storage device, install Ubuntu and other necessary software, and your ready to go.
Another possibility is this one from Amazon
Sapphire 52036-01-40G Fusion E350, E350, A50M, LONG DIMM, S3, Mini-ITX Motherboard n/a Mini ITX DDR3 1066 AM3 Motherboard – Pure White
Either way, you will pay about $80 for the motherboard with a built in graphics card.