Tagged: rtl2832u

RTL-SDR and RDS Spy with HDSDR

On YouTube user pe1etr shows us a video where he uses his RTL-SDR combined with HDSDR, Virtual Audio Cable and RDS Spy to decode a distant RDS signal. RDS Spy is a free advanced software program capable of decoding weak RDS signals contained in many broadcast FM radio stations.

RDS stands for Radio Data System and is a digital signal embedded into broadcast FM signals. It is used by radio stations to display the name of the radio station and current song playing on an LCD screen.

HDSDR & RDS Spy side by side

ViewRF – RTL-SDR Spectrum Analyzer Software for the BeagleBone Black Released

Last month we showed a video of a spectrum analyzer project by Stephen Ong. He used a BeagleBone Black (mini embedded Linux capable computer similar to a Raspberry Pi), a touch capable LCD screen, and an RTL-SDR dongle to create a portable spectrum analyzer.

Now Stephen has released ‘ViewRF’, which is the software that powers his spectrum analyzer. It is released under the GPL licence. Also on his post are the download and install instructions.

Spectrum Analyzer using Beaglebone Black and RTL-SDR

Rain Scatter 10 GHz Reception with the RTL-SDR

YouTube user feri67000 who last month showed us that the RTL-SDR can receive 10 GHz signals with a cheap avenger LNB PLL now shows an interesting experiment where he uses a technique known as rain scatter to receive a 10 GHz beacon with his satellite dish pointed in the opposite direction of the beacon transmitter.

Usually communications at 10 GHz are line of sight only, but by using the rain scatter technique, the 10 GHz signal can be bounced off a precipitation cloud and received with line of sight to the cloud, rather than the transmitter.

rain scatter 10ghz LX1DB beacon

NOAA Weather Satellite Antenna and Software Guide

Over on the SDR for mariners blog, author Akos has written two new beginners posts on getting up and running with receiving and decoding NOAA weather satellite APT images.

The first post discusses antennas that are useful for NOAA satellite reception, and shows how to build a homemade turnstile and QFH antenna. His second post shows a beginners guide to the software that can be used to decode the APT signal in order to obtain a live weather satellite image.

sdrformariners_apt_image QFH Antenna

RTL-SDR Running on an Aria G25

Blogger and ham radio enthusiast F4GKR has written a brief tutorial post on his blog showing how he got an RTL-SDR working with an Aria G25, and in another post some benchmarking results. The Aria G25 is a very small low cost, Linux capable embedded computer, similar to the Raspberry Pi.

He was able to get rtl_tcp running with a 2 MSps sampling rate and found it used about 60% of the CPU.

Aria G25 running the RTL-SDR

New Command Line Utility: rtl_power

A new command line wideband spectrum monitor utility called ‘rtl_power’ has been released by keenerd on Reddit. See the original thread here. This tool let’s you gather signal data over a very wide area of the frequency spectrum, and then that data can be used to find active areas of the spectrum.

Rtl_power is a small CLI tool for logging wide swaths of bandwidth. You can specify any chunk of spectrum, with any FFT bin size and any logging rate. (For sane values of any.)

For example

rtl_power -f 150M:200M:2k -i 10 logfile.csv

will monitor everything between 150MHz and 200MHz. The resolution will be at least 2kHz fine. It will integrate for 10 seconds and dump those numbers to the logfile. The structure of the logfile is:

date, time, Hz low, Hz high, Hz step, samples, dbm, dbm, ...

So it is not quite the traditional CSV file. Each frequency hop gets its own line and the frequencies of each column are extrapolated.

Coupled with a python script, a heatmap can be generated from the excel data.

I’m scanning the region between 150MHz and 160MHz, where there is local emergency services chatter. Each pixel is 10kHz wide and 10 seconds long, over a period of seven hours

rtl_power heatmap

This is command line tool is somewhat similar to the Scanner Metrics SDRSharp plugin, which allows large areas of the frequency spectrum to be monitored from within SDRSharp.

More Comparisons Between the E4000, R820T, FC0013 and Linrad and SDRSharp

A few days ago we posted a video by sm5bsz showing some comparisons between the E4000, R820T and FC0013 tuners, and also a comparison between the special linearity gain mode driver in Linrad and standard Osmocom driver in SDRSharp.

Now sm5bsz, programmer of Linrad and the special gain modes for the E4000 has done another test using only Linrad, which more fairly demonstrates the difference between the various tuners, and the effect of the special gain drivers in Linearity mode. He writes

In this video RTL2832 dongles are compared for sensitivity, spurs and intermodulation. The difference between the Linrad linearity mode and the original Osmocom gain setting is demonstrated as well as spurs in R820T and FC0013.
Which one to prefer depends on the local RF Environment and whether a selective filter is used between the antenna and the dongle.

Note: The Linrad vs SDRSharp video has been removed by the uploader.

Finally in this video, he also compares the standard Osmocom driver to the sensitivity mode available in the modified gain profile drivers. He writes

The sensitivity mode has very poor performance for signals far away from the passband, but it allows about 10 dB better dynamic range for interferences within the passband. Sensitivity mode is for usage with a selective preamplifier while the Osmocom gain mode is a reasonable compromise. The Linrad linearity gain mode is for use without filters in difficult RF Environments.

e4000 sensitivity mode

Linrad can be downloaded from here and the modified Osmocom drivers with linearity and sensitivity gain profiles for the E4000 can be downloaded here. SDRSharp can also use the modified Osmocom drivers with Linearity and Sensitivity modes with this plugin by Zefie.

Perseids Meteor Reflection Observations with the RTL-SDR

In this video YouTube user ek6rsc shows a timelapse of meteor reflection observations during the yearly Perseids meteor shower which occurred in 2013 during August 10-15. To do this he uses an R820T RTL-SDR tuned to 59.25 MHz, and the HROFFT software to do the recording.

Meteors entering the atmosphere can cause radio frequency reflections which may allow extremely distant radio signals to be received briefly. Reception of such a signal may be a good indicator that a meteor has fallen. A good informational guide on meteor scatter with the RTL-SDR can be found in this pdf file by Marcus Leech.

2013 Perseids Aug10-15 radio observations Meteor reflection 59.25Mhz