Detecting the Perseids Meteor Shower with an RTL-SDR Passive Radar

Amateur radio hobbyist EB3FRN has made a post on his blog showing how he was able to use an RTL-SDR to act as a passive radar and detect meteors from the Perseids meteor shower. To do this he tuned to 143.050 MHz which is the the frequency of the Graves radar, a French space surveillance radar used to spot satellites and detect their orbits. He then used the Baudline software to record the radar signal scatters which occur when a meteor reflects the Graves radar signal.

Graves Radar - 2013 Perseids Meteor Shower

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SDR Touch 1.7 Public Beta Released

The programmer of the Android based software defined radio app SDR Touch has released a public beta of version 1.7. The programmer writes that the new features include

New multi-threaded core, native audio support, experimental x86 support is included as well. Although most changes are under the hood (the release is build for performance boosts), probably the most obvious non-performance enhancement is FM STEREO.

If you intend to install the beta you will need to first uninstall your existing version of SDR Touch, which will cause you to loose any presets you may have set. The programmer warns that this version may be unstable as it is in beta.

You can download the beta from http://sdr.martinmarinov.info/beta/AndroSDR17beta.apk

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Beginners Antenna Guide

Akos from the SDR for mariners blog has just written another post that is a guide on constructing and buying beginner level antennas for the RTL-SDR. The post shows how to build a simple ground plane antenna out of wire coat hangers, and also discusses monopoles, telescopic antennas, rubber duckys and discone antennas.

Simple Coat Hanger Groundplane
Wire coat hanger ground plane Antenna
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Upconverter Comparison: Nooelec Ham it Up vs SDR Up 100

A few weeks ago Akos from the SDR for Mariners blog did a review of the SDR Up 100 Upconverter, and he promised to compare it with the Nooelec Ham-it-up Upconverter when it arrived. He has now done the comparison, and written about it on his blog.

For each test he used a gain of 0dB and the same 20 foot random wire antenna. Interestingly, his results show that the SDR Up 100 significantly outperforms the Ham-it-up upconverter. We believe that this may be as the SDR Up 100 has an LNA built into it whereas the Ham it up does not.

Update: Akos has now included comparisons with various RTL gain settings.

upconverterCompare
SDR Up 100 vs Ham It Up
Nooelec vs Up 100 comparison
Comparison Images
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Passive RADAR With a Dual Coherent Channel RTL-SDR

Juha Vierinen from the Kilpisjarvi Atmospheric Imaging Receiver Array has been working on a Dual Coherent Channel RTL-SDR modification. This modification essentially involves using the same clock source for two RTL-SDR dongles, which can be done by desoldering and removing the clock on one dongle, and then using a cable to connect the clock from another dongle to the clock input of the desoldered dongle.

RTL-SDR Dual Coherent
Dual Channel Coherent RTL-SDR Receiver

Juha then was able to use his new dual coherent channel RTL-SDR to create a passive RADAR system. To do this, he connected the two RTL-SDRs to two log periodic Yagi antennas. From this setup he was able to detect airplanes and meteor echoes. An image cap and video showing RADAR detections over time is shown below.

Passive RTL-SDR RADAR
Passive RTL-SDR RADAR
Longer rtlsdr fm radio passive radar video

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SDRLab: An RTL-SDR Interface to LabVIEW for Educational Purposes

If you’re familiar with the LabVIEW software, there is now an RTL-SDR interface called SDRLab by Beküldte Andris. The software is able to capture the I/Q data from the RTL-SDR, and with that you can do educational experiments in LabVIEW, which is great for students. The author has also implemented a FM demodulator.

ha5kfu_sdrlab_release

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Using the RTL-SDR as a Software GPS Receiver

Dr. Carles Fernandez-Prades, Dr. Javier Arribas and Dr. Pau Closas have published an academic paper showing how they were able to implement an RTL-SDR based GNSS (Global Navigation Satellite System) receiver in software.

What they have done is use their open source GNSS software receiver program with a RTL-SDR connected to an active GPS antenna. An active GPS antenna requires DC power to be passed to the LNA in the GPS antenna through the antenna connection, so a Bias-T network is required to ensure DC power does not enter the RTL-SDR dongle.

More information can be found on their webpage here.

Rtlsdr_with_lna_patch_GA27

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Decoding D-STAR Headers with the RTL-SDR

D-STAR or Digital Smart Technologies for Amateur Radio is a digital voice and data protocol used in amateur radio. I was tweeted a link earlier which shows how the RTL-SDR can decode D-STAR text messages and headers (link is in Italian but Google translate can help, and the pictures show more than enough information). By using SDRSharp and stereo mix you can tune to a D-STAR signal, and pass the audio to a command line based decoding program (dstar.exe) which can be downloaded from the above link, which will then decode D-STAR text messages.

dstar7

Here is also an older video showing D-STAR decoding with HDSDR in action.

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