This weeks video on the TechMinds channel explores the various online web SDRs that are available to access for free. Accessing these online SDRs does not require any hardware apart from a PC and internet connection, although of course you are then receiving signals from a different location to yourself.
In the video he shows how to access the SDR# Spy Server Network which mostly consists of Airpsy and RTL-SDR units, the SDR-Console V3 Server network which consists of a wide array of different SDRs, the browser based WebSDR network which is mostly soundcard based SDRs but also RTL-SDR and other SDRs, and finally the KiwiSDR network which is made up of KiwiSDRs.
Using Software Defined Radio Without SDR Hardware - WebSDR
Over on his YouTube channel Frugal Radio has released the second episode in his 2020 SDR Guide series. In this video, Frugal Radio shows how to connect to remote SDRs such as KiwiSDR OpenWebRX, WebSDR, SDR-Console v3 Servers, and SDR# SpyServers. He shows how to use these remote SDRs to monitor long range aviation channels, amateur radio operators, and VHF Public Safety channels in the US. He also demonstrates how to decode HFDL signals from aircraft using WebSDR and free software, and verifies the aircraft locations via online tracking sites.
2020 SDR Guide Ep 2 : How to use over 500 remote SDRs free online (webSDR, KiwiSDR & HFDL decode)
OpenWebRX was first developed by Andras Retzler and is and open source program that allows users to make RTL-SDRs, KiwiSDRs and other SDRs accessible over the internet via a web browser. Recently the OpenWebRX public directory at SDR.hu, also run by Andras, has been closed. In the past we've posted about Andras' decision to move on from OpenWebRX and how sdr.hu went from public access to requiring an amateur radio callsign to access. Now Andras has decided to take the final step and close sdr.hu for good. The sdr.hu website now reads:
The SDR.hu project has been finished
I'd like to say a big thanks to everyone who joined my journey with this project!
I hope you had a good time listening on the site, and learnt some things about SDR. The purpose of this site was to provide a technological demonstration for amateur radio operators about Software Defined Radio, and I hope this goal has been reached. As this website was a one-person hobby project, with my tasks and responsibilities growing, and my focus moving to other projects at which I hope to make a greater positive impact, I'm unable to further develop SDR.hu and protect it from abuse.
Furthermore, I think this site has some good alternatives now. Nevertheless, in my opinion amateur radio receivers should be shared with strict access control in the future.
If you have more questions, feel free to consult the FAQ.
73!
Andras, HA7ILM
We want to note that although KiwiSDR makes use of OpenWebRX, the KiwiSDR project is not affected by this closure as they use a custom fork of OpenWebRX, and there is an official KiwiSDR directory at kiwisdr.com/public, a map version at map.kiwisdr.com, and an SNR score directory at snr.kiwisdr.com. Unfortunately the one major drawback is that these directories do not list public RTL-SDRs or other SDRs running OpenWebRX as only sdr.hu did that.
Also, although Andras has stopped development on OpenWebRX, a fork of the project led by Jakob Ketterl (DD5JFK) is alive and well at github.com/jketterl/openwebrx and openwebrx.de.
Back in early January we posted about how the popular web based SDR and RTL-SDR compatible receiver software known as OpenWebRX was officially discontinued by the original author. However, thanks to it's open source licence, code contributor Jakob Ketterl (DD5JFK) has been able to continue developing the code and is taking over as the lead developer on his own fork of the code.
Recently he released version 0.18.0 of OpenWebRX which includes a few major upgrades including the much needed shift to Python 3, and the inclusion of multiple new decoders for DMR, D-Star, YSF, NXDN, FT8, FT4, WSPR, JT65, JT9, APRS and Pocsag.
Hello fellow radio enthusiasts,
with great excitement I would like to announce the availability of OpenWebRX Version 0.18.0 as public release. This is the first release of the project in some time, and the first release since I started working on it, so I’m more than happy to bring this to you.
What’s new? Quite a lot, actually. For those that haven’t had the chance to follow the progress of the project in the past months, here’s a quick overview:
Most of the server code has been rewritten for better flexibility, stability and performance. The project is now fully based on Python 3.
Large parts of the frontend code have been updated or polished.
The new core now supports multiple SDR devices simultaneously, as well as switching between multiple profiles per SDR, allowing users to navigate between multiple bands or frequencies.
Added support for demodulation of digital voice modes (DMR, D-Star, YSF, NXDN).
Added support for digital modes of the WSJT-X suite (FT8, FT4, WSPR, JT65, JT9).
Added support for APRS.
Added support for Pocsag.
Bookmarks allow easy navigation between known stations.
Background decoding can transform your receiver into an automatic reporting station, including automatic band scheduling.
The integrated map shows digimode spots as well as APRS and YSF positions.
OpenWebRX 0.18.0 is available via the following channels:
Please check out our updated Setup Guide along with the rest of the documentation on the Wiki!
Questions, ideas, problems? Get in touch with the community at [email protected]!
Best regards and vy 73s
Jakob DD5JFK
We're so glad to see that this excellent software isn't dead in the water and is in fact thriving. We will continue to follow the Jakob's and the OpenWebRX communities' future developments. If you are interested, you can follow OpenWebRX development on the OpenWebRX groups.io forum.
In the blog post, they show how it's possible to use a RTL-SDR and Raspberry Pi running OpenWebRX to remotely monitor the radio spectrum over the internet. This of course has been done many times before, however, the novel thing here is the use of the Balena cloud platform which makes installing and managing the Raspberry Pi running OpenWebRX much easier.
Balena has a has a special balenaOS image that is first burned on the Raspberry Pi's SD card. The OS image is pre-generated with your home WiFi details, so upon boot it automatically connects to the internet and can be accessed on the balenaCloud dashboard. At that point you can easily remotely push the pre-made Balena "sdr-spectrum-monitor" docker image to the Pi from the Balena online dashboard. This docker image has OpenWebRX and the RTL-SDR drivers already installed on it. It's then a simple matter of connecting to OpenWebRX via the local IP address as you would normally.
This is quite a nice system as it avoids needing to perform the "fiddly" steps of setting up WiFi, connecting to the Pi, determining the Pi's IP address, and installing the RTL-SDR drivers and OpenWebRX software manually.
Balena also has a very simple way to make the OpenWebRX server accessible from outside your network. The only steps required are to set a port variable in the Balena cloud dashboard, and enable the "public device URL" option. No need to fiddle around with unblocking ports or dynamic DNS services.
Balena.io appears to be free for personal use, allowing you to add and manage up to 10 devices before needing to pay.
RTL-SDR & OpenWebRX Installed and Managed via Balena Cloud.
The KiwiSDR is a US$299 HF SDR that can monitor the entire 0 - 30 MHz band at once. It is designed to be web-based and shared, meaning that the KiwiSDR owner, or anyone that they've given access to can tune and listen to it via a web browser over the internet.
OpenWebRX is code originally created by András Retzler and a modified version runs on the KiwiSDR devices. This code is what allows them to be accessed online by a browser and was popularized by it's use in the KiwiSDR. The original code can also be used by other compatible SDRs such as the RTL-SDR.
Recently András released news that he is discontinuing work on OpenWebRX due to interest in other projects, but it will remain on GitHub as open source code. András also notes that the security of OpenWebRX will soon be in question as it utilizes Python 2, which has been designated end of life on January 1 2020. In addition, if you've been following OpenWebRX since the beginning, you'll know that in the past OpenWebRX was involved in an legal/ethical issue over open source licencing with KiwiSDR. Although the problems with KiwiSDR were resolved amicably, Andras also references his frustrations with similar situations to do with his code being forked again and again.
We note that maintenance and development of the KiwiSDR OpenWebRX code will continue as they are considered separate projects. Due to some confusion, we importantly reiterate that the KiwiSDR product is unaffected by OpenWebRX being discontinued. Although KiwiSDR is based on OpenWebRX they use their own custom branch of the software that is maintained by the KiwiSDR owners and not by András.
András also runs the popular sdr.hu OpenWebRX/KiwiSDR directory, which was/is considered the main directory for finding and accessing public KiwiSDR and other SDR devices running OpenWebRX. Recently the directory was restricted, and now can only be accessed by those with a ham radio callsign. It is unclear why this decision was made as sdr.hu was very popular with shortwave listeners and radio newbies who are typically not hams. But the sdr.hu FAQ notes "The purpose of the site is to serve amateur radio. I decided to restrict access to the receiver list in order to protect the site and its purpose in the long term."
Over on YouTube Corrosive from the SignalsEverywhere channel has uploaded a new video that shows how to install the the PlutoWEB Firmware on a PlutoSDR, which allows OpenWebRX to run directly on the PlutoSDR itself. OpenWebRX is a SDR streaming platform that enables people to connect to the SDR remotely over the internet. Multiple users can access the SDR at the same time as well. Many public OpenWebRX servers running on KiwiSDRs can be found at sdr.hu as the KiwiSDR uses it by default.
The PlutoSDR is a low cost (typically priced anywhere between $99 - $149 depending on sales) RX/TX capable SDR with up to 56 MHz of bandwidth and 70 MHz to 6 GHz frequency range. It also has an onboard FPGA and ARM Cortex-A9 CPU which can be used to run programs on the PlutoSDR itself.
Corrosive's video shows us how to install PlutoWEB which is an unofficial firmware package for the PlutoSDR. It comes preinstalled with many programs such as OpenWebRX and dump1090. He then shows how to set up OpenWebRX and then shows a demo of it in action.
Thanks to Zoltan (aka Veryokay on YouTube) for submitting information about his Inmarsat STD-C EGC live stream setup. His setup allows him to access the Inmarsat STD-C signal from anywhere in the world over the internet, thanks to the use of an OpenWebRX server. Inmarsat STD-C is a geostationary satellite service that provides information for search and rescue, as well as news, weather and incident reports for mariners. We have a tutorial from a few years ago which shows some example messages. OpenWebRX is an efficient SDR streaming server platform that allows you to access RTL-SDR's and other SDRs from anywhere in the world via an internet connection.
In his setup Zoltan uses a Raspberry Pi 3, RTL-SDR Blog V3, L-band LNA and L-band antenna for receiving and processing the signal. Power is provided via a Power over Ethernet (PoE) adapter, and the whole thing is placed outside, in a weatherproof plastic lunchbox.
The video shows the hardware, and then goes on to describe the software setup, along with a demonstration of the OpenWebRX stream. More information as well as the link to his publicly accessible OpenWebRX Inamrsat STD-C stream can be found on his blog post.
