Over on YouTube user Albert Schäferle has uploaded a short video showing his reception of some radar pulses and their corresponding echoes. He uses rtl_fm and pipes the output into Baudline which is used to display the radar waveform. On the video description he writes:
Receiving direct and (supposedly) reflected pulses from an L-band radar in Učka, HR (Lockheed Martin AN/FPS-117). The receiving station was 83 km away, with clear LOS. Center frequency is 1258 MHz (one out of four that this frequency-agile radar head is using). The receiver is a RTL-SDR dongle (R820T tuner IC) with a 2-dipole collinear array (tuned for 403 MHz) and approx 7 m of Belden 1694A RG-6 coax.
rtl_fm output was piped to baudline, which is the software shown in the video. The IQ sampling rate is 2 MHz; the transform is a complex STFT (size=2048 samples, Blackman window). This is a 0.008x speed playback of 15 ms of recording. The (again, supposedly) reflected pulses are obviously more time-local with a shorter transform window size, e.g. 512 samples http://i.imgur.com/sAHWhwD.png
The effect of pulse compression is quite evident http://www.radartutorial.eu/08.transm… The direct-reflected delay is approx 278 µs (~42 km from receiver, in a simple 2D, along beam, normal incidence model). I should add that this “reflection delay” effect does not usually show up. There’s another fainter echo closer to the pulse, but I suspect that it could be a time-sidelobe of the main pulse: a side effect of pulse compression. Anyway, I must state that I have no formal knowledge on radar topics. So you’d better take all this with a grain of salt 😉
The beta version of the popular ADS-B decoding software RTL1090 has been updated to version 3. Version 3 comes with a simple radar visualization scope built into the software, which allows you to see aircraft directly in the RTL1090 software.
To use the app, you will need an Android device that supports USB OTG, which most Android devices on Android 4.0+ should support. You will also need a USB OTG cable, and an RTL-SDR dongle. You may want to consider a USB OTG cable that has a second port for external charging capabilities, as the RTL-SDR can drain the battery quickly.
The app is cheaply priced at under $2, so give it a try!
In order to do this he used the Linux based dump1090 ADSB-B decoder and hub software on his main PC. Lui was even able to compile and run the ADS-B hub portion of dump1090 on his Windows PC using Cygwin, but was unable to get the decoder part to work. It doesn’t matter though because the dump1090 hub can receive data from any ADSB decoder, such as ADSB#. His results look very promising as can be seen by the timelapse of plane traces in the image below.
Large ships and passenger boats are required to broadcast an identification signal containing position, course, speed, destination, and vessel dimension information to help prevent sea collisions. This system is known as the “Automatic Identification System” or AIS for short. There are dedicated AIS receivers intended to be used on boats, or by hobbyists, but they can be expensive. A radio scanner, or the cheap RTL-SDR software defined radio (or a more advanced SDR such an Airspy) can be used to receive these signals, and with the help of decoding software, ship positions can be plotted on a map.
This tutorial will show you how to set up an AIS receiver with the RTL-SDR. Most parts of this tutorial are also applicable to other software radios, such as the Funcube dongle, Airspy and HackRF, or even regular hardware scanners if a discriminator tap is used, but the RTL-SDR is the cheapest option.
Safety Warning: This probably should not be used a navigational aid on a boat as the field reliability of the RTL-SDR or other software radios is not proven. This guide is intended for land based scanner hobbyists.