Shortwave listening and everything radio including reviews, broadcasting, ham radio, field operation, DXing, maker kits, travel, emergency gear, events, and more
Many thanks to SWLing Post contributor, Mike (KA3JJZ), who writes:
Have you ever heard of the SW Radiogram digital broadcasts? These are produced by Dr. Kim Andrew Elliott and started way back when as the VoA Radiogram. They are now carried on 2 other stations (WRMI and WINB) on a schedule (check every week for a summary of images) that you can find on the SW Radiogram website;
These tests consist of both text and images. Currently MFSK32 and 64 have been used, and an occasional ‘secret’ mode has been slipped in at the end of the transmission. The last time this was done, the mode was PSK125R.
You might ask how you can receive these broadcasts, and what you need to decode them. We have 2 wiki articles that go into great detail – one for PCs, and one for Android devices – here;
Yes, you can copy these broadcasts using an Android powered phone or tablet using an application called TIVAR. John VK2ETA has written a quick start guide which is available on the SourceForge website as well as the RadioReference wiki (the links are provided in the article)
These articles are written for folks who are just getting their feet wet, so the above articles touch on radios (no, you don’t need to use an expensive radio, though many do), antennas, propagation and more. The most popular software is FLDigi, but if you happen to have MultiPSK or DM780 (part of Ham Radio Deluxe), they can be used as well. Links are given for the software and any available support.
Along with Tumblr, SW Radiogram has both a Facebook and Twitter page (where members often post decoded images) here…
Thank you, Mike! Yes, I’m a big fan of the SW Radiogram–the community that has formed around this particular shortwave program is quite amazing. Thanks for all of the tips!
Many thanks to SWLing Post contributor, Ed, who writes:
SWLing Post readers might be interested in learning about Gospell’s newly-announced DRM receivers and active antenna products. The GR-22 “pocket-sized” “full-wave” receiver that’s supposed to be available for purchase by June 2020 seems especially interesting.
(Source: Gospell Press Release)
Gospell to announce the DRM monitoring system and imminent release of portable DRM receiver, and more
Chengdu, China – Gospell, a leading supplier of pay TV system and equipment, satellite TV receiving products and microwave products, announces its product lineup for IBC 2019. The company will debut several new products featuring DRM (Digital Radio Mondiale) for both consumer and industry market, including:
GR-22 – Portable DRM/AM/FM Receiver
GR-227 – DRM Car Adapter
GR-301 – DRM/AM/FM Monitoring Receiver
GR-310 – Audio Broadcast Monitoring Platform
GR-AT3 – High Performance Active HF Antenna
GR-22 is a sleek and classy portable radio from Gospell, the contemporary stylistics of exterior design fits in your personal style, crystal clear DRM digital radio and AM/FM brings practicality and comfort to your daily enjoyment. Despite its pocket-size, it’s a nifty full wave band receiver packed up in a tiny body that enables you to explore a wide variety of radio stations. It is also future-proofed for the next generation DRM-E technology. You have access to all the presets, station names, program details and even Journaline news on the easy to ready large LCD in a simple and intuitive way. Sleep timer set your radio to automatically switch off or wake up at your convenience. Listen to your favorite radio programs anywhere you like with 4 x AA batteries or connect it to mains. GR-22 is a multi-functional radio that is flexible to your listen habits. GR-22 will be available for purchase on Q2 2020.
GR-227 is a car digital radio adapter that utilizes most advanced interference and noise cancellation technology to receive digital radio in car while achieving the best audio quality and serve it to the car audio system over aux cable or by transmitting over an unused FM frequency. The receiver is fully compatible with DRM standard that is being deployed over the world, with its latest audio codec xHE-AAC. Based on software defined radio technology, GR-227 is ready for the emerging DRM-E standard that extends the DRM broadcast to FM band.
GR-301 is a high performance monitoring receiver that supports DRM, AM and FM. GR-301 supports the collection of key parameters of audio broadcasting, including SNR, MER, CRC, PSD, RF level, audio availability and service information. The collection and uploading of parameters meets DRM RSCI standards. The GR-301 can work independently or be deployed with other receivers to become a node in the service evaluation network. The GR-301 supports the xHE-AAC audio codec and is capable of handling the latest DRM-E standard through software upgrades.
GR-310 is a management platform designed for audio broadcast monitoring and receiver control purposes, it manages the geographically distributed GR-301 receivers. The platform can formulate receiving schedules, configure the receivers to perform receiving tasks, perform real-time browsing of the reception status, store historical data, and visualize the statistic data in a intuitive way. In addition to monitoring and analyzing data, the GR-310 platform also supports real-time audio monitoring and configuration of alarm conditions, alarms will be triggered when rules are met.
GR-AT3 is a high-performance active monopole antenna with reception frequency ranges from 0.3 to 50MHz. It is designed to work in harsh environments with respect to strong man-made noise and stern natural conditions. It is compact and easy to install, supplied accessories enable rapid installation. The antenna is comprised of a wide band amplifier in an IP67 waterproof aluminum body together with an active element made of a stainless-steel. The solid construction ensures durability and maintenance-free operation.
“We’re constantly working to ensure we’re bring the latest technology in our product”, says Haochun Liu, assistant to general manager, “These products underscore the Gospell’s commitment to providing easy access to high quality information at affordable prices. Both consumer and industry can benefit from it.”
Gospell will be exhibiting at IBC 2019 in the Amsterdam International Broadcasting Convention (IBC) Hall 3 C67, September 13-17. To schedule a meeting at IBC 2019 or access a sample of the featured IBC showcase, email [email protected]
About Gospell
Established in 2001, Gospell Digital Technology Co Ltd (GOSPELL). is a hi-tech enterprise with R&D, manufacturing, business consultancy and planning, trade, delivery, project implementation and after sales service, acting as a complete DTV and triple-play solution provider for Digital TV/OTT related projects. Headquartered in GOSPELL INDUSTRIAL PARK at Chenzhou, Hunan Province for CPE related production manufacturing, GOSPELL also has its office in Shenzhen for business/marketing management and administration, in Chengdu for R&D and headend/transmitter system production/debugging and Customer Service Center, and in 12 cities in China as well as international offices in India, Africa and Mexico.
Thank you for sharing this, Ed. Looking through the press release, I don’t see any DRM radios where they note shortwave reception, however, the GR-22 is being called a “full wave band receiver.” Perhaps “full wave” is their way of indicating shortwave reception?
It looks like the GR-22, and all of the products listed above, are squarely targeting the new DRM market in India.
Pirate radio stations are appearing on unlicenced DAB digital multiplexes in Dublin and Cork, and more are planned for other cities in Ireland.
The “FreeDAB” platform, now carrying around ten stations, was born out of frustration over the procedures in place to broadcast legally on DAB in Ireland.
During the recent 12-month legal DAB multiplex trial operated by ‘éirdab’ in Cork, a radio station wanting to broadcast via this method would need to pay upfront for a five-year Section 71 licence (a list price of €14,000 (plus VAT)) and wait up to five months for the application to be processed.
But waiting five months for a licence and paying five years up-front to be on a 12-month trial are just two of the issues holding back DAB in Ireland.
The technology required to broadcast a multiplex is now easier to acquire and is mostly controlled by software whilst costs to broadcast illegally via the multiplexes also appear to be very low.[…]
Many thanks to SWLing Post contributor, Bill Patalon, who shares a link to the following article on Extreme Tech:
Last Tuesday at 1744 UTC (1:44 PM EDT) UR3RM, a ham radio station in Ukraine blindly sent out a message on 7040.138 kHz. It was automated. It was text. Maybe someone would hear it. Maybe not.
The “maybe not” part is easy to understand because UR3RM’s transmitter was putting out one milliwatt, .01 watts. To put that in perspective, a Class 2 Bluetooth transmitter, the ones good for around 30 feet, run 2.5 milliwatts.
UR3RM was using a mode called WSPR for Weak Signal Propagation Reporting. Unlike most of ham radio, this is a one-way mode. Not only is there little expectation anyone will be listening, but there’s even less that the signal would make it back. Radio propagation isn’t always a two-way path.
WSPR’s biggest selling point is you can do it on the cheap. It’s easy to set yourself up for not much more than $100 and often a whole lot less. And, though a ham radio license is needed to transmit, anyone can put up a receiver. And the US ham license test is multiple-choice, all published and online.[…]
[…]For years, NASB members have wanted to replace (or at least augment) the poor audio quality of analog SW with the crystal-clear sound of digital SW radio, specifically the Digital Radio Mondiale standard developed in Europe that is now being used in China and India.
[…]There are some DRM radios in use now, which is why some NASB members are offering limited DRM broadcasts alongside their regular analog SW transmissions.
“But the current generation of DRM SW receivers cost about $100 each, whereas you can buy a cheap analog SW radio for as little as $10,” said Dr. Jerry Plummer, a professor at Austin Peay State University in Clarksville, Tenn., and frequency coordinator for U.S. SW station WWCR. “Given that the audiences being targeted by NASB members are largely in the third world, the lack of inexpensive DRM receivers keeps them listening tDRMo analog shortwave.”
[…]Given the NASB’s interest in low-cost DRM receivers, it was no coincidence that Johannes Von Weyssenhoff was invited to speak at the annual meeting. Von Weyssenhoff said his StarWaves manufacturing firm (www.starwaves.de) has the technology, capability and existing prototypes to build DRM radios for $29 each, but only if the sale order is large enough to deliver economies of scale. (He also estimated $18 DRM modules could be built for installation in other radio models.)
“Twenty-nine dollars is doable at volumes staring at 30,000 receivers,” Von Weyssenhoff told Radio World. “Even smaller quantities would be possible at this price for very simple radios — for example, without graphics displays — but these would be special projects that had to be discussed individually. But even more advanced radios with Bluetooth or premium designs will be possible to offer at a reasonable price,” he said — as long as the sales orders was in the tens of thousands or more.[…]
Many thanks to SWLing Post contributor, Mike Ladd (KD2KOG), who shares the following guest post. Note that the following tutorial is also available as a PDF (click here to download).
Basics to decoding Inmarsat L-Band signals using the RSP SDR
by Mike Ladd
Note: CHECK WITH YOUR LOCAL LAWS BEFORE DECODIING ANY SIGNALS FROM THE INMARSAT SYSTEM
(some text taken and edited from the RTL-SDR Blog website)
This document is not a definitive guide to Satcom, L-Band transmission or the Inmarsat system. This is a collection of information that I have found scatter throughout the internet and re-compiled into a document, this document. My aim is to help you get started and hopefully guide you in the right direction. Expect typographical mistakes, inaccuracies, or omissions
Inmarsat is a communications service provider with several geostationary satellites in orbit. Inmarsat provides services such as satellite phone communications, broadband internet, and short text and data messaging services. Geostationary means that the Inmarsat satellites are in a fixed position in the sky and do not move.
The Inmarsat 3-F(x) satellites have transponders transmitting data in L-Band (1.5 GHz) that can be decoded.
The modes we will cover in this document are Aeronautical (Classic Aero or ACARS) and Inmarsat-C (STD-C) using an RSP1a, RSP2/2pro or RSPduo connected to the SDR-Kits modified L-Band patch antenna. The Inmarsat system is not limited to only these types of networks. We are limited to the decoders available. https://en.wikipedia.org/wiki/Inmarsat
Two of the most popular decoding applications are JAERO used for ACARS and Tekmanoid STD-C Decoder used for decoding STD-C NCS transmissions on the Inmarsat 3-F(x) satellites
Virtual Audio Cable: A virtual audio cable allows you to pipe audio from application (SDRuno) into another application (a decoder like JAERO) digitally. I will assume SDRuno is already installed with your device attached and functioning properly.
You can now download a virtual audio cable package.If you already have a virtual audio cable package installed, you can skip to the next section. If you don’t have a virtual audio cable application installed, you only need to choose one and only install one of the two, either one works fine
Close any running apps, install the virtual audio cable and reboot your computer. When your computer boots back to your desktop, your computer will now have a virtual audio cable pair installed on the system.
You can verify by going to your Control Panel and double clicking the Sound icon. VB-Cable and Virtual Audio Cable will only install a single virtual audio cable pair, one is for the input (Recording) and one is for the output (Playback). A single pair is all that is needed (as shown below).
JAERO
(some text taken and edited from the JAERO website)
JAERO is a program that decodes ACARS (Aircraft Communications Addressing and Reporting System) messages sent by satellites (in this case Inmarsat) to Airplanes (SatCom ACARS). This is commonly used when airplanes are well beyond VHF range.
JAERO also allows for decoding and demodulation of voice calls, due to local laws and privacy, I will not show or discuss how to do this. You can find more information about that JAERO feature online.
JAERO can be downloaded from the link provided on the first page of this document. After downloading the installer, simply double click the setup file and install it on your primary drive.
Tekmanoid STD-C Decoder
(some text taken and edited from the USA-Satcoms website)
Inmarsat STD-C is a data or message-based system used mostly by maritime operators. An Inmarsat C terminal transmits and receives on L-Band to various geosynchronous satellites that service each major ocean region.
The Tekmanoid STD-C decoder will decode STD-C Inmarsat EGC (enhanced group call) and LES (land earth station) messages. Some of these messages contain private information. Reception of these messages may not be legal in your country; therefore, your local laws should be checked.
The Enhanced Group Call (EGC) service is a message broadcast service with global coverage (except the poles) within the Inmarsat-C communications system. Two of the services provided are:
FleetNET and SafetyNET
FleetNET is used to send commercial messages to individuals or groups of subscribers (for example, individual companies communicating with their own Mobile Earth Stations (MES). SafetyNET is used for broadcasting Maritime Safety Information (MSI) such as Navigational warnings, meteorological warnings, meteorological forecasts and other safety related information (including Distress Alert Relays) from official sources.
The LES station acts as an interface (or gateway) between the Inmarsat space segment and the national/international telecommunications networks.
The Tekmanoid STD-C decoder requires Java JRE in order to run. The link for the Java runtime environment is on page 2 of this document. For information contact the developer direct [email protected]
There are alternatives to using the Tekmanoid STD-C decoder, but in my opinion the other decoders available do not perform as well on low end systems or even work without needing “helper” applications to be installed. Tekmanoid STD-C decoder is very easy to use and works great on my low-end system using minimal system resources.
Putting all the pieces together
ACARS and STD-C messages will transmit via the Inmarsat satellite deployed within your coverage area/region, you will need to choose the Inmarsat satellite that is closest to your coverage area.
Note that only different frequencies are used between ACARS transmissions and STD-C transmissions. You will only need to receive from one of the available 3-F(x) Inmarsat satellites.
L-Band ACARS transmissions are in the 1.545 GHz range but STD-C messages are on fixed frequencies (shown on page 8)
Since STD-C transmissions are broadcasted on fixed frequencies, we want to monitor the TDM NCSC channel, again these are fixed for the following Ocean Regions. Choose the region closest to your location (page 9).
Inmarsat satellite: Inmarsat-4 F1 (IOR) Direction: 25° East Frequency: 1.537.10 GHz
Inmarsat satellite: Inmarsat-4 F1 (POR) Direction: 143.5° East Frequency: 1.541.45 GHz
I will assume you have located the Inmarsat satellite that covers your region. I suggest using a compass on your mobile phone to pinpoint the general direction. The direction is in ° (degrees). I am referencing true north, not magnetitic north (traditional analog compass). https://en.wikipedia.org/wiki/Magnetic_declination
You can also download an app for your smartphone called Satellite AR (Android and IOS). After you locate the correct direction of the Inmarsat satellite, you will want to place the L-Band patch on a flat metal surface. I have read that the receive pattern of this patch antenna is z (about 85-90°, straight up). Point the top of the antenna facing the Inmarsat satellite. Using the roof of my car worked just fine, just remember to point the front of the antenna at the satellite.
Launch SDRuno and click the PLAY button, remember that if the RSP(x) is in ZERO IF mode, give frequency separation between the VFO (top frequency) and LO (bottom frequency). In LOW IF mode this is not needed. I suggest running a sample rate of 2 MHz, larger bandwidths are not needed.
The SDR-Kits patch antenna requires that the RSP(x) Bias-T be enabled. The Bias-T option is enabled within the MAIN panel of SDRuno. See the SDRuno manual located here. https://www.sdrplay.com/docs/SDRplay_SDRuno_User_Manual.pdf view page 17.
Select the Virtual audio cable as the output in SDRuno, this is selected via the RX Control panel. SETT. button and clicking on the OUT tab.
Have SDRuno’s Volume slider (RX Control) at about 35-40%
Upper sideband is recommended but I found the best mode to use for L-Band ACARS or L-Band STD-C decoding is DIGITAL with a filter width of 3k.
Be sure to set a proper step size (right click the RX Control frequency readout). The step size is not important for STD-C transmissions because these signals are only on one frequency for the satellite in your region but L-Band ACARS signals will be on many frequencies. Setting the proper step size will avoid issues when you point and click on signals you want to decode using the JAERO decoder.
You will want to center the signal with a little breathing room within the AUX SP filter passband. The filter slopes are very sharp. Keep the signal centered and away from the extreme edges (red markers).
Select your virtual audio cable within the decoder’s audio input preferences.
The Tekmanoid STD-C decoder sound properties are located under Settings in the toolbar menu.
JAERO’s sound settings is located under the Tools menu and Settings.
For STD-C decoding use the frequency from page 8 of this document, remember we only want to monitor the TDM NCSC channel in the Tekmanoid STD-C decoder.
For JAERO decoding, I suggest you start in the 1.545 GHz portion and observe the constellation in the JAERO decoder.
The signal to noise ratio (SNR) needed for successful decoding in these decoders will need to be greater than 7dB. When working with a weak satellite signasls, try decimating the signal using SDRuno’s decimation feature. (MAIN panel, DEC).
I hope this document helps you get started decoding Inmarsat L-Band transmissions from the I3-F(x) satellites. I am sure I missed some key features, remember this is only a primer/basics to decoding these types of transmissions.
Warmest of 73,
Mike-KD2KOG
Many thanks for sharing your tutorial here on the SWLing Post, Mike! This looks like a fascinating activity that really requires little investment if one already owns an RSP or similar SDR. I’m certainly going to give L-Band a go! Thank you again!
