patience
some basic skills in handling GHz PCB boards
excellent skills and equipment for application and soldering of very small SMD devices
an oscilloscope and other electronic measuring equipment
the desire to understand a very complex matter of encoding and decoding
patience

Building a 1090 MHz receiver is nothing to be done between two uncompleted projects and just for a weekend. Expect problems, problems and more problems. If one of the above challenges is a no, leave the project alone.

Local restrictions

Building and/or operating a 1090 MHz receiver may not be permitted in your country. Check your local legal standards first.

Root reference

Original thread: http://www.mikrocontroller.net/topic/135459#new
Forum article: http://www.mikrocontroller.net/articles/1090_MHz-ADS-B-Receiver

These references are in German language. Most of the information available from there is published on this website in English language, too.

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General

We have designed the miniADSB-Receiver from analysis of the three available commercial receivers. All their frontends show certain similiarities. The frontends are throughly analyzed at http://www.mikrocontroller.net/articles/1090_MHz-ADS-B-Receiver#Hardware for reference.
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Also we have taken care of availability and costs of parts and the ability to manufacture and solder a SMD PCB at home. The result is a compromise. Please consider the before mentioned when judging the design. Do not expect a high sensitivity and behind the horizon looking high-end receiver. But it is good enough for detecting aircraft within 150 km and at the airport.

If you can go cheaper or/and better with a different design or a modified Sat-tuner please do so and let us know, but dont complain.

Concept

This is the general concept of the 1090 MHz-receiver. It is a zero-IF receiver. A receiver with LO, mixer and selective IF filter may be technoligally superior, but here is why we dont need it:

The commercial receivers work the same
There is less trimming and tuning equipment required
As there is no LO the device can be used inside an airplane

Here is what we have:

SAW-Filter - RF-Amplifier (MMIC) - SAW-Filter - Log Amp (Detector) - (Video Amplifier) - Comparator - Microprocessor or FPGA or another Signalprocessor - PC-interface

The bold components are the subject of the design on this webpage. The others are not!!

The video amplifier is optional, but highly recommended. Its design is outside of the scope of this project. However connecting the detector output directly to the comparator will also yield usable results.

There are two video amp, comparator and signal processing designs out there already, one for AVR and another for PIC. We dont think it is beneficial to add a third one. Please go to these websites to learn about the micro interface and programming and start from there:

Design for AVR controllers:
http://www.lll.lu/~edward/edward/adsb http://www.lll.lu/~edward/edward/adsb/SimpleAdbsReceiver.html

Design for PIC controllers:
http://rxcontrol.free.fr/PicADSB/index.html http://rxcontrol.blogspot.com/search/label/ADS-B%20Decoder

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