Tagged: sdr sharp

TechMinds: Testing the ISM Packet Decoder Plugin for SDR Sharp

Over on the TechMinds YouTube channel Matt has uploaded a video demonstrating the use of the ISM Packet Decoder plugin for SDR# which was released a few months ago. The plugin authors website also contains more information about the installation and features of plugin.

The plugin makes use of the well known rtl_433 software behind the scenes, which is a command line based RTL-SDR compatible decoder for various wireless ISM band devices such as weather stations, car keys, tire pressure sensors, doorbells and various other remote controlled devices. The plugin GUI makes using and displaying data from rtl_433 much more convenient.

ISM Packet Decoder Plugin For SDR Sharp - RTL 433

SDR# Frequency Manager + Scanner Plugin Updated to Version 1.6

The widely used Frequency Manager + Scanner Plugin for SDR# has recently been updated to version 1.6. It can be downloaded from sdrsharpplugins.com. Note that this version requires SDR# version 1248 or newer, so run install.bat if you haven’t done so in a while. The new features are as follows:

Frequency Manager

  • The Frequency Description is now displayed in the upper-right corner of the spectrum analyzer, along with the indicator for multiple database entries for that frequency.
  • As a result of moving the above information to the spectrum analyzer, the Frequency Manager panel is now 35% smaller.
  • The Clipboard Monitor now optionally watches the clipboard for frequencies you might have copied from the internet; and if that can be converted to a MHz value it tunes the radio to that frequency.
  • Function Keys F1-F10 can now be used to tune to a preset frequency.


  • A new Minimum Signal Strength Line is displayed on the spectrum display. This, along with real-time display of the current signal’s strength when the scanner is running, let you see at a glance how that signal compares to your scanner settings. In addition you can use customize the line with one of 6 line patterns.
  • Current Signal Strength in dB is displayed in the upper right corner of the spectrum analyzer, just after the Frequency Description.
  • Timeout and Watchdog timers’ indicators are now displayed in the upper right corner of the spectrum analyzer.

SDR# Now with Noise Blanker

The latest version of SDR# has now been updated to include a noise blanker plugin. A noise blanker can reduce impulsive noises like those created by spark gaps and electric motors. Other SDR programs like Linrad and HDSDR have had noise blanker functions for a while so this is a welcome addition to SDR#. Below is a comparison of the noise blanker turned on and off on a noisy CW signal.

To update SDR# to the latest version simply run install.bat again. Take note that updating will remove any plugins you have added to the SDRSharp.exe.Config file so you may wish to save it first.

Noise Blanker Off

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

Noise Blanker On

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

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]
SDR# IF Digital Noise Reduction Plugin

Installing SDR# on OSX

SDR# is the most commonly used Software Defined Radio receiver GUI that is used with the RTL-SDR. Natively, it runs on Windows, but since it is written in C#, it can also run on Mac OSX and Linux with Mono. Installing SDR# on OSX using Mono is a little more complicated compared to simply running it on Windows however.

To help with this, Jan Szumiec has written a simple guide on installing SDR# using Mono on OSX. The guide includes the steps of installing Mono, the Xamarin Studio Mono IDE, the rtl-sdr libraries and then compiling the SDR Sharp sources and symlinking the Mono runtime to the native libraries.

Update: This is no longer possible as the SDR# code is not available anymore.

SDR Sharp on OSX
SDR Sharp on OSX

SDRSharp Frequency Manager Plugin updated to Version 1.4

The commonly used frequency manager and scanner plugin for SDRSharp has been updated to version 1.4. The new features include:

Frequency Manager

  • Frequency Presets – there are now 10 frequency presets you may use to store and recall favorite frequencies.


  • A new Signal Strength Indicator displays a real-time measure of a frequency’s signal strength compared to the Minimum Signal Strength that you set. The indicator shows the signal strength as it bounces below and above your minimum, and also shows when the “Seconds wait for transmission” and “Watchdog” timers have been triggered.
  • The Scanner Configuration window now has two tabs which organize scanner behavior into Rules settings and Performance settings.
  • Snap to next Step Size: a new checkbox lets you force the scanner to tune a scanned frequency to the SDR# step size, or instead allow it to tune to the actual detected peak signal strength of a frequency.
  • Update a frequency’s Date when monitored: a new checkbox that causes the scanner to record the current date for a frequency that is already in your database, when the scanner lands on that frequency.
  • Adjacent Frequency Rejection: a new setting that lets you define the width of the area around a tuned frequency that is used to monitor signal strength after tuning to a frequency. This reduces the influence of adjacent strong frequencies that “splatter” into the tuned frequency’s step size or bandwidth size.
  • Faster scanning speed: Scanning speed has been improved yet again, and is now faster than the improvements in version 1.31. On my equipment I now average 1.6 GHz scanning speed as measured with the built-in benchmark tool on a range scan.
  • Improvements to the busy-frequency detection process.

The updated plugin can be downloaded from http://www.sdrsharpplugins.com.

RTL-SDR used as a Cheap Real Time Spectrum Analyzer

The rtl-sdr dongle can be been used as a super cheap $20 real-time spectrum analyzer. This is great as commercial spectrum analyzers can run from hundreds to thousands of dollars.

First of all, SDRSharp and other SDR software packages are essentially spectrum analyzers themselves. They all have real time frequency spectrum and waterfall viewers. They are however, not exactly portable.

A portable spectrum analyzer is shown by amateur radio hobbyist and blogger OZ9AEC. He has combined an rtl-sdr dongle, a low cost portable Linux computer known as Beaglebone, and an LCD screen, and turned them into a portable spectrum analyzer. OZ9AEC shows a video demo of his project in this video.

A cheap spectrum analyzer can be useful in many situations. For example, Marek Wodzinski uses the rtl-sdr as a spectrum analyzer for optimizing his FPV radio transmissions. Many other people seem to be interested in a rtl-sdr for this purpose too.

A Google groups post discussing use of the rtl-sdr dongle as a spectrum analyzer is here.