SDR# now with IF Stage Noise Reduction Algorithm

SDR# has recently been updated to include an IF stage digital noise reduction algorithm. Previously digital noise reduction could be done at the audio output stage, but now it can be done to the IF signal as well. Performing digital noise reduction on the IF stage appears to work much better than at the audio stage. Update SDR# by running the install.bat file again.

Here are some comparison audio files tested on a noisy NFM voice signal for listening.

Original Signal

[audio https://www.rtl-sdr.com/wp-content/uploads/2014/03/IF_NR_OFF.mp3]

IF Noise Reduction (set to -12 dB)

[audio https://www.rtl-sdr.com/wp-content/uploads/2014/03/IF_NR.mp3]

Audio Noise Reduction (set to -80 dB)

[audio https://www.rtl-sdr.com/wp-content/uploads/2014/03/AF_NR.mp3]
sdrsharp_if_nr
SDR# IF Digital Noise Reduction Plugin
Tweet
Share
Reddit
Vote
Email

Decoding HOT, EOT & DPU Train Data

On YouTube user Curt Rowlett has uploaded a video showing how he was able to decode HOT, EOT & DPU signals from trains using an RTL-SDR. Head of Train (HOT) and End of Train (EOT) signals are used on trains to transmit telemetry data such as brake line pressure and monitor accidental separation of the train. Distributed Power Unit (DPU) signals are control signals that are used to control remote DPU’s on long trains. DPU’s are locomotives which are placed in the middle or rear of a train to help more evenly distribute pushing and pulling power over the entire train.

Curt used the SoftEOT and SoftDPU software programs to monitor and decode these signals. This software can be downloaded from the softEOT Yahoo! Group after requesting and being accepted into membership.

HOT signals can be found on 452.9375 MHz, EOT signals on 457.9375 MHz and DPU signals on 457.9250 MHz.

Decoding HOT, EOT & DPU Train Data

Tweet
Share
Reddit
Vote
Email

Ham it up Upconverter 3D Printed Case YouTube Giveaway

Over on YouTube Eric William has posted a video about his competition where he is giving away two 3D printed ham-it-up upconverter cases. The ham-it-up is an upconverter that can be used with the RTL-SDR to allow it to receive HF (0-30 MHz) frequencies. To enter the competition you simply need to go to Erics web forum and post about what you use SDR for in the competition thread. The competition is open only for North American viewers and ends on May 19 2014.

Tweet
Share
Reddit
Vote
Email

Transmitting DAB with the HackRF

A RTL-SDR.com reader has written in to let us know about his project involving transmitting Digital Audio Broadcasting (DAB) using GNU Radio and the HackRF. DAB is a digital radio technology that is used to broadcast radio stations. He uses the CRC-DABMUX and CRC-DABMOD software to modulate an audio file into DAB and then uses a GNU Radio python script to write the modulated signal to the HackRF for transmitting.

Tweet
Share
Reddit
Vote
Email

Decoding 2x AIS Channels with SDR Console, AISMon and OpenCPN

YouTube user k2nccvids has posted a video showing him decoding and plotting both AIS channels simultaneously on a Windows PC with free software. To do this he uses SDR Console and two AISMon instances. SDR Console is a general purpose SDR GUI that supports the RTL-SDR. One of it’s major advantages over other SDR software is that it can tune to multiple signals in the same swath of tuned bandwidth simultaneously and output their audio to different virtual audio cables.

k2nccvids used two AISMon instances, each one connected to a separate virtual audio cable outputting AIS audio from SDR Console. He set AISMon to output decoded UDP packets on two different ports. Then he created two UDP listeners in OpenCPN for plotting, one for each port.

Tweet
Share
Reddit
Vote
Email

RTL-SDR Wide Spectrum Analyzer

Over on YouTube claudio giuliani has posted a video of his RTL-SDR Wide Spectrum Analyzer software. The software is written in the basic for gambas language and uses an RTL-SDR software defined radio to plot a wide chunk of the frequency spectrum by sweeping over it. It looks to be similar to the RTL-SDR Scanner software. Currently it is only available for Linux.

RTL-SDR Wide Scanner
RTL-SDR Wide Scanner
RTL_SDR Wide spectrum analyzer

Tweet
Share
Reddit
Vote
Email

RTL-SDR DSD Call Log Recorder

Programmer Tyler Watt has been working on software that automatically logs each call from an RTL-SDR running DSD (Digital Speech Decoder) and then stores it in a time stamped database as an mp3 file. There is also a web front end for the database which allows public users to search and play recorded calls.

Recently Tyler updated his code by rewriting it in PHP and making it multiplatform.

The old version of his web front end in action for his local P25 calls can be viewed here, and the newer one can be found here.

Tweet
Share
Reddit
Vote
Email

Reverse Engineering Radio Controlled Power Outlets with Help from the RTL-SDR

Radio controlled electricity power outlets are outlets that can be turned on or off using a wireless radio controlled remote. Over on the blog leetupload.com the author has written an article showing how he was able to reverse engineer the wireless power outlets radio protocol.

The author used an RTL-SDR and SDR# to listen to the outlets wireless AM transmissions at 434 MHz. He then recorded the signal audio and then used audacity to view the waveform. By analyzing the audio output he discovered that the signal was a Non-Return-To-Zero (NRZ), pulse width modulated (PWM), Amplitude Shift Keying / On Off Keying (ASK/OOK) signal.

Later he was also able to use the RFCat USB dongle to transmit an on off signal from his computer. RFCat is an USB dongle that is capable of transmitting on 433 MHz.

RTL-SDR Software Radio used to Reverse Engineer the Wireless Power Outlet
RTL-SDR RTL2832U Software Radio Audio output Analyzed in Audacity for Reverse Engineering a Wireless Power Outlet
Remote Control Outlet Replay With RFCat

Source Hackaday

Tweet
Share
Reddit
Vote
Email