Category: RTL-SDR

Khanfar Spectrum Analyzer: Signal Analysis Tools for the RTL-SDR

Thank you to M. Khanfar for submitting news about the release of his new spectrum analyzer, sweeper, and FM Radio demodulator tools for the RTL-SDR. The tools are freely released, however, they do not seem to be open source.

THIRD PARTY SOFTWARE VIRUS WARNING: We just want to note that Khanfar's software shows a few positive results for viruses on VirusTotal. These are most likely false positives, but please use this software at your own risk, especially as it is not open source.

The first tool M. Khanfar is releasing is the Khanfar Full Spectrum RTL-SDR Sweeper tool, a wideband spectrum analyzer for the RTL-SDR. It allows the RTL-SDR to produce a spectrum sweep over a large bandwidth by rapidly re-tuning the frequency and plotting each 2.4 MHz live sweep sequentially. This is the same concept used by previous tools like rtl_power and Spektrum.

Khanfar RTL-SDR Sweeper
Khanfar RTL-SDR Sweeper

The second tool released is the Khanfar Advanced Spectrum Analyzer. This tool allows you to view the live spectrum from an RTL-SDR in various visualization modes.

Khanfar Spectrum Analyzer
Khanfar Spectrum Analyzer

The third tool is Khanfar-FM-Radio, a text-based wideband and narrowband FM demodulator for the RTL-SDR.

Khanfar WFM-NFM Demodulator
Khanfar WFM-NFM Demodulator

M. Khanfar notes that all tools can open multiple instances of themselves, allowing them to be used use multiple RTL-SDR dongles on the same machine.

In the video embedded below, M. Khanfar shows his three software applications in action.

Khanfar Spectrum Analyzer

A 3D Printed V-Dipole Guide for the RTL-SDR Blog Dipole Kit

Thank you to Denis for submitting his 3D printable V-dipole guide for our RTL-SDR Blog Dipole Antenna set. The guide holes the dipole at a 120-degree V-shape angle, which is ideal for receiving polar-orbiting satellites such as NOAA and Meteor at 137 MHz. 

Back in 2017, Adam 9A4QV wrote about how a V-Dipole could be used as a very simple yet effective antenna for receiving weather satellites. Since then, it has become a popular beginner's choice for receiving weather satellites.

In the past, we've also seen other 3D-printed V-dipole holders, such as this one by f16v1per. However, f16v1per relies on cable ties to hold the elements in place, whereas the design by Denis simply slides in place.

If you don't have an RTL-SDR Blog Dipole Antenna, you can also build a V-dipole out of an electrical terminal block and a different 3D-printed part, as shown in this previous post.

3D Printed V-Dipole Holder
3D Printed V-Dipole Holder

Saveitforparts: Listening in on Russian Soldiers Hijacking US Military Satellites

Over on the saveitforparts YouTube channel, Gabe has uploaded a video showing how he uses WebSDR streams to show how Russians, including Russian soldiers, are using old US Military satellites for long-range communications around Ukraine.

In the '70s and '80s, the US government launched a fleet of satellites called "FLTSATCOM," which were simple radio repeaters up in geostationary orbit. This allowed the US military to easily communicate with each other worldwide. However, the technology of the time could not support encryption or secure access. So security relied entirely on only the US military's technological superiority of being the only one to have radio equipment that could reach the 243 - 270 MHz frequencies in use by these satellites. Of course, as time progressed, equipment that could reach higher frequencies became commonplace.

In the video, Gabe explains how many Russian soldiers involved in the Ukraine war are using these legacy satellites to communicate with each other. He notes that apart from voice comms, some channels are simply Russian propaganda and music, as well as some channels that appear to be jammed. Gabe also notes that the "UHF Follow-On Satellite" (UFO) satellites that were launched as recently as 2003 are also being hijacked, as they also have no encryption or secure access.

In the past, we also posted a previous video by Gabe about attempting to receive these satellites from his home in North America. However, on that side of the world, the satellites are being hijacked by Brazilian pirates instead.

Russia Is Hijacking US Military Satellites

Skies-ADSB Updated to V2.0.3

Back in 2022, we first posted about the release of skies-adsb, a browser-based app that uses ADS-B data from an RTL-SDR to provide a 3D view of the air traffic around your area. Recently skies-adsb has been updated from version 1 to version 2, bringing with it several improvements.

The new improvements include:

  • Generate custom GeoJSON map layers from Natural Earth, FAA, and OpenStreetMap data
  • Aircraft trails visualization
  • Enhanced map renderer with multi-layer vector support:
    • Aerodromes
    • Airspaces
    • States / Provinces
    • Counties
    • Urban areas
    • Roads
    • Rivers
    • Lakes
  • New aircraft follow camera controls

The YouTube video below by the author demonstrates some of the new features.

skies-adsb v2 release - RTL-SDR ADS-B 3D plane tracking app

Saveitforparts Checks out the Discovery Dish

Over on his YouTube channel 'saveitforparts,' Gabe has uploaded a video checking out and reviewing our Discovery Dish product that we successfully crowd-funded on CrowdSupply back in December 2023.

Discovery Dish is designed as a low-cost way to dive straight into backyard satellite experiments, including receiving L-band and S-Band weather satellites as well as Inmarsat satellites. It also offers an easy entry into making galactic Hydrogen line observations.

The dish is a 70cm prime focus dish, that can easily be broken down into three parts for easy storage and transport. The feeds are fully integrated, meaning that the feed antenna, LNA, and filtering are all in one unit and built into a waterproof enclosure. This means there is no need to purchase individual components and figure out waterproofing.

In his video, Gabe unboxes the Discovery Dish, builds it, and uses the L-band feed to receive a few images from GOES 16, Meteor M3, Meteor M4, and METOP weather satellites. He goes on to successfully test reception with the S-band feeds on NOAA weather satellites, before testing out the Inmarsat feed and successfully receiving signals. Finally, Gave notes that he hopes to test out the Hydrogen Line feed in a future video.

Checking Out The Discovery Dish - A Simple & Easy-To-Use Satellite Antenna For Everyone!

Video on the Basics of SDR for Hackers

On YouTube, An0n Ali posted a video providing a good overview of the basics of using a software-defined radio for hacking. The video introduces RTL-SDR and how it can be used to listen to unencrypted communications, the HackRF and how it can be used for replay and jamming attacks, and the Flipper Zero, noting how it is a more beginner-friendly entry into the world of RF security.

SDR Basics for HACKERS!

A USB-C Mod for RTL-SDR Blog V3/V4 Dongles

Over on GitHub, umbertoragone has uploaded some schematics for a USB-C modification he's made for RTL-SDR Blog V3 and V4 dongles. The modification removes the stock USB-A plug on the dongle, and instead replaces it with a USB-C connector mounted on an adapter PCB.

The repo contains all the gerbers, BOM, and assembly details required to replicate the modification. He notes that he is also selling a pre-made USB-C adapter board over on his Tindie or Lectronz store for US$4 (currently out of stock).

Let us know in the comments if you would be interested in seeing an official USB-C version of the Blog V3 and V4 line of dongles. Previous polling has indicated that USB-A is still the preferred choice by a wide margin, but attitudes may have changed over the years.

A USB-C Modification for RTL-SDR Blog V3 and V4 dongles.
A USB-C Modification for RTL-SDR Blog V3 and V4 dongles.

Locating an Intermittent Interferer with a KrakenSDR

Over on YouTube Thomas Brinkoetter has uploaded a video demonstrating his experience with the KrakenSDR, and how he used it to find an intermittent interferer that he set up for a test. The video was prepared to support the RF Interference and Mitigation class at the IWCE trade show Las Vegas March 17 and 18th 2025.

If you weren't already aware, KrakenSDR is our 5-channel coherent radio based on RTL-SDRs, and it can be used for applications like radio direction finding. It can currently be purchased either directly from our krakenrf.com website, or from Crowd Supply or Mouser.

The test involved his wife keying up a repeater for one second out of every 15 seconds. In the video Thomas was able to successfully locate the transmitter with an antenna array and KrakenSDR mounted in his vehicle.

Locating an intermittent interferrer with the Kraken SDR