Paolo Romani (IZ1MLL) has recently released version 3.0 of his SDRSharp PDF Guide which we posted about last in March of this year. As before the document is a detailed guide about how to use SDRSharp, which is the software provided by Airspy. While intended for Airspy devices, SDRSharp also supports a number of third party SDRs, including the RTL-SDR, and it is the software we recommend starting with when using an RTL-SDR.
The guide is now 61 pages long, and covers all the settings, UI customization, included and third party plugins, and use of some external decoders.
In the previous episode Rob from the Frugal Radio YouTube channel showed us how to decode HF ACARS using PC-HFDL and an HF capable SDR such as the Airspy HF+. In that episode he mentioned that it is possible to decode HF ACARS using a WebSDR as well.
In this weeks episode, Rob shows us how to do just that, making use of WebSDR receivers and the PC-HFDL software. Like the previous episode we see how to plot the aircraft HF ACARS position data on Google Earth and how to read and interpret some example messages received.
In Rob's latest episode of his excellent aviation communications series on his Frugal Radio YouTube channel he shows how to decode aircraft HF ACARS (HFDL) using a software defined radio. HFDL is short for "high frequency data link", and is a method aircraft use for sending text and data communications to ground stations. It is an alternative to VHF or satellite ACARS communications methods.
In the video he shows how he's been able to receive HFDL from all over the world using a simple HF dipole antenna and an Airspy HF+ Discovery. He goes on to show how to find HFDL signals, and how to decode signals using SDR# and the PC-HFDL software. Finally he shows examples of aircraft received, and how to interpret some of the information being received, including location information.
How to decode HF ACARS (HFDL) free with your SDR - Monitoring Aviation Communications Episode 8
Airspy is currently holding a 20% off summer promotion which runs from June 28th until Julty 4th 2021. The sale is active at all participating resellers, which includes our own store where we have the YouLoop on sale for US$27.96 including free shipping to most countries in the world, instead of the usual US$34.95. Please note that due to new EU VAT collection laws, EU customers must purchase the discounted YouLoop from our eBay or Aliexpress stores.
The YouLoop is a low cost passive loop antenna for HF and VHF. It is based on the Möbius loop design which results in a high degree of noise cancelling. However the main drawback is that it is a non-resonant design, which means that it works best when used with ultra sensitive receivers like the Airspy HF+ Discovery.
Over on YouTube Rob from Frugal Radio has uploaded a video reviewing our new L-Band Patch antenna which we released for sale late last month. The patch is currently on a release sale for US$44.95 including free standard airmail shipping to most countries. We will be ending the sale this Wednesday at which point the price will go to US$49.95, still with free standard airmail shipping to most countries. The patch can be purchased from our web store at www.rtl-sdr.com/store.
In the video Rob demonstrates the patch receiving Inmarsat signals strongly, and decodes a few AERO signals using JAERO. He shows that the patch works on any RTL-SDR with bias tee capability as well as an Airspy Mini. Lastly he compares the unit against the SDR-Kits patch.
We note that we are also supplying a kit for a giveaway to Frugal Radio subscribers that we will announce in an upcoming video coming out a few days time.
RTL-SDR updated L-band patch antenna review - perfect for your SDR radio!
UPDATE: Giveaway information now available in the latest video below.
SDR# (SDRSharp) is one of the most popular free software defined radio programs available with RTL-SDR support. Recently it has been updated to version 1811 and the new version brings improved performance and also improves RTL-SDR compatibility with some systems. The changelog reads:
Date: Mon Mar 29 15:03:09 2021 +0200
More DSP optimizations;
Many fixes for RTL dongles (mainly workraounds for old libs);
Revert to libusb 126.96.36.19904 for backward compatibility;
Revert to portaudio 2016 for backward compatibility;
Check the latest and greatest SDR# release with more performance optimizations and better processing quality for #airspy devices. The #rtlsdr crowd will also be happy with the improved compatibility.
@lambdaprog (the SDR# programmer) has also tweeted showing how well SDR# can run on a 10 year old i7 4700 laptop with the new performance improvements. With a huge 160 MSPS baseband IQ file, the software is seen to be using very minimal CPU.
Over on their YouTube channel GNU Radio have uploaded a recent talk by Aaron Rossetto titled "A Look at Project 25 (P25) Digital Radio". The talk explains the North American public safety P25 system in great depth, and is a good watch for anyone looking into details on how the system works in a deeply technical way. He later shows some examples of his P25 decoding and recording setup. Slides can be found here, and the video is posted below.
Agenda: In this presentation, I will introduce Project 25 digital radio, with a strong emphasis on its use in North American public safety trunked radio systems, and to describe experiments monitoring and decoding P25 traffic using GNU Radio code.
In the past we've posted several times about how 1.42 GHz Hydrogen Line amateur radio telescopes used with RTL-SDRs or other SDRs for Hydrogen line observations of the galaxy. Recently Hackaday ran a post highlighting a project from "PhysicsOpenLab" describing an 11.2 GHz radio telescope that uses an Airspy SDR as the receiver.
Celestial bodies emit radio waves all across the radio spectrum and typically observations can be made anywhere between 20 MHz to 20 GHz. Choosing an optimal frequency it is a tradeoff between antenna size, directivity and avoiding man made noise. For these reasons, observations at 10-12 GHz are most suitable for amateur radio telescopes.
The posts by PhysicsOpenLab are split into two. The first post highlights the hardware used which includes a 1.2m prime focus dish, and 11.2 GHz TV LNB, a wideband amplifier, a SAW filter, a bias tee, and the Airspy SDR. The LNB converts the 11.2 GHz signal down to 1.4 GHz which can be received by the Airspy. Once at 1.4 GHz it's possible then to use existing commercial filters and amplifiers designed for Hydrogen line observations.
The second post explains the GNU Radio based software implementation and the mathematical equations required to understand the gathered data. Finally in this post they also graph some results gathered during a solar and lunar transit.
Finally they note that even a 1.2m dish is quite small for a radio telescopic, but it may be possible to detect the emissions from the Milky Way and other celestial radio sources such as nebulae like Cassiopeia A, Taurus A and Cygnus A a radio galaxy.