Online SDRs: Impacting the Way We Listen to Shortwave

Online SDRs: Impacting the Way
We Listen to Shortwave

(This post is an edited version of an article I wrote for "The World of Shortwave Listening" column of The Spectrum Monitor magazine - December 2019 issue. Further details on this excellent publication are available at www.thespectrummonitor.com)

Here in southeastern Australia, I still love playing with what some jokingly call “real radios”. I gain much joy from operating my collection of gear - Yaesu FTDX3000, FRG100, FRG-7, Kenwood TS2000, R5000, Tecsun PL-680 and Sangean ATS909. There is something about sitting down to a wall of rigs, routed through a small mixing desk, and attached to a variety of switchable antennas that I find deeply satisfying, offering hours of great fun.

We are all aware of the monumental impact that the Internet has brought to the world. The all-pervasive presence of the web has affected just about everything we do and will continue thus forevermore. Even the simple act of switching on a radio and tuning around to listen for a distant shortwave station thousands of miles away now has Internet options. Who would have thought this just 30 years ago?

Global Tuners

Hams being hams, we soon found that the Internet could be utilized for experimental online radio operations with availability being extended to access by the general public. Some will remember the 1990s with excursions into JavaRadio and DXTuners, which later morphed into GlobalTuners (circa 2007). Indeed, GlobalTuners (https://www.globaltuners.com/) is still around today, providing listening opportunities using a range of physical and Software Defined Radios (SDR) through their URadioServer software connections to the Internet. You can stream a range of receivers from Icom, AOR, Yaesu, and JRC, plus an increasing number of SDRs such as the RTL and SDRPlay. There is something magical about controlling someone else’s radio over the Internet. GlobalTuners and its predecessors have provided listeners with a great service for many years now, especially amongst utility and aero DX enthusiasts. However, the interface is quite dated by today’s standards - there is no waterfall display, the latency in tuning to new frequencies can be annoying, and the limitation of permitting only one user at a time to operate a radio means that GlobalTuners is showing its age.

WebSDR

A popular online service enjoyed by shortwave listeners and amateur radio operators is the WebSDR software, authored and maintained by PA3FWM, which can be found at http://websdr.org/. Developed in 2008 and reactivated in

The WebSDR at the University of Twente, Netherlands.

2012 after a hiatus of nearly two years, the WebSDR at the University of Twente at Enschede in the northeastern part of the Netherlands is a favourite amongst shortwave listeners. With its frequency range from 0 to 29.160 MHz, a zoomable and adjustable waterfall, a well-chosen range of bandwidth filters, variable noise reduction, the usual AM/SSB/CW/FM modes, a separate S-meter plot over time, and other features, this receiver provides comprehensive coverage of broadcasters both in Europe and beaming to Europe. The antenna is a mini-whip based on the design by PA0RDT, sitting on top of a well-grounded metal roof at 65 feet. That setup provides wonderful, mostly noise-free reception.

At the WebSDR website, you will also find numerous other SDRs available scattered across other parts of the globe. Many are maintained by hams so they focus on specific frequency ranges within and around the HF ham bands, plus some VHF and UHF coverage. As you scroll through the list, you will see just about every type of antenna in use - including verticals, dipoles, loops, yagi beams, and even a log periodic antenna. The great advantage and a game-changer that these WebSDRs have over GlobalTuners is that many listeners can tune the receivers simultaneously - there’s no waiting around for another user to complete their listening session.

The little KiwiSDR is the mainstay receiver
used on the SDR.hu website.

KiwiSDR   

UPDATE: Since this blog post was written, the SDR.hu project has closed down. However, the http://kiwisdr.com/public/ website is still providing a great service - Rob

In more recent times, the KiwiSDR website has provided free access to a wonderful range of global online SDRs. http://www.kiwisdr.com/). There are numerous features for listeners to play with on the site including adjustable waterfall, high/low-cut filter adjustment, easy BFO tuning, variable noise gate, variable AGC, and a list of extensions for decoding WSPR, FSK, FAX, NAVTEX, SSTV and other modes. A few receivers are time-limited but most of those are fairly generous. Occasionally, receivers will be taken offline for software updates, testing or if the ham is using the antenna for his own transmitting activities. The only other downside is that the receivers are restricted to between two and eight users at any one time, however, a few operators now offer multiple receivers at their location. Some of the better installations (e.g. with better performing antennas, lower local noise, etc) are more popular with users who fill up all the available slots, so a waiting period is sometimes the result.

Different Uses for Online Receivers

With access to all these fabulous online receivers dotted across the globe, how can we best use them to enhance our radio activities? Below are some ways that I utilize these invaluable resources.

I enjoy monitoring international broadcasters. I check their choice of frequencies for specific transmissions, listen to see how well their broadcasts are being heard in the targeted zone, and if their signal suffers any co-channel or adjacent channel interference from other broadcasters. I find this especially useful around the two major changes of the A and B transmission seasons at the end of March and the end of October each year. Often, I am surprised at the collisions occurring between two stations transmitting to the same region on the same frequency. Even broadcasters beaming to quite different parts of the world on the same frequency can cause mutual interference in their own targeted regions. With so much vacant space to choose from on the SWBC bands these days, it astonishes me just how much broadcasters can still get in the way of each other! The choice of frequencies used will change for the summer and winter seasons. Checking the propagation path between the transmitter and receiver can provide some interesting observations on ionospheric conditions at specific times of the day, month and solar cycle. Yeh, I know, it’s a bit nerdy but, hey, that’s just me!

Radio Guinée, in Conakry, Guinea Republic
arrives with a good signal at an online SDR in Brazil.

These days much is written in some of the shortwave-focused Facebook forums about the current poor propagation conditions. There are many people whinging about the lack of signals on the higher shortwave frequencies, and perhaps with good cause! But it is worth remembering that when the bands are dead in your part of the world at a certain time of day, they may very well be great in another part of the globe. I like to compare reception conditions in my own neck-of-the-woods on the same bands in other places. In the process, I have learned much about the best times of day and night for listening on specific bands in, say, Africa and the Middle East. Yep….also nerdy!

But the most obvious reason for using remote receivers is for the simple joy of tuning in and enjoying broadcasts that cannot be heard in my part of the world. In southeastern Australia, there are many broadcasts that we miss. In the 70s and 80s, nearly every major European country offered services to Australia and New Zealand on a daily basis in time windows coinciding with our evenings and mornings. In the 90s, we began to notice that those services we had come to rely upon were disappearing one-by-one. But now with remote receivers, those European nations still operating on shortwave are easily accessed. And, of course, all types of low powered stations such as the domestic Latin American broadcasters or the flea-powered European pirate operators are heard with receivers right on location.

Handy Ham Tool

For those of us with amateur radio licences, these remote receivers are fabulous for checking the quality and strength of our transmissions. I regularly monitor the signal quality of both my SSB and digital transmissions with local receivers close by. My transmissions are recorded, played back and assessed for any evidence of distortion, overmodulation and any unpleasant tone quality. Receivers further afield are useful for judging both how far my signal is travelling and the prevailing propagation conditions, providing me with live and realistic feedback. I can actually hear for myself if my signal is really a “5 and 9”!

Recently, I hooked up a WSPR beacon kit for antenna testing and monitoring of propagation conditions. 200mW into a variety of antennas and running over 24 hours with results providing invaluable feedback via the WSPRNet aggregator site (http://wsprnet.org). But, as mentioned earlier, some of the remote KiwiSDRs now have a WSPR decoding extension built right into the online receiver. And it appears to work quite well. So, if a ham in another location is not monitoring a specific band at the time my beacon is transmitting, I can utilize one of the SDR.hu receivers in a location some hundreds or even thousands of miles away.

Ethical Reception Reporting and Online Receivers

However, I have one negative observation regarding how some people are using online receivers. It concerns what I consider to be the misplaced ethics of reporting and QSLing stations using the Internet as the conduit. Recently, there have been a few SWLs in one continent sending reception reports to very low powered pirate stations on another continent using a remote receiver in the city of the pirate broadcaster. Of course, we can expect that these stations are happy to accept reception reports - they are delighted to see that people are responding to their broadcasts and writing with email requests for eQSLs. But if, for example, 10 people scattered around the world use the same remote receiver to hear the one pirate station and send off reception reports, the broadcaster is effectively accumulating 10 reports from the one online receiver that may be located in the next suburb or town!

Call me old-fashioned but in my view, those listener emails do not constitute a true reception report in the traditional sense. After receiving responses from the pirate stations, some listeners then head to over to Facebook to brag about their eQSL. Personally, I don’t think this is in the spirit of DXing, which has always been about long distance listening. Sending a report to a very low powered station you heard on the Internet from a receiver near the transmitter is not my idea of DXing or the QSL hobby. I suspect some readers will disagree with me, but that’s OK. To each his own!

A world map shows the distribution of online receivers available at the KiwiSDR website.

My Favourite Online Receivers 

So what are some of the better remote SDRs for serious listening? Things to consider when selecting receivers include good antennas, perhaps even multiple switchable antennas, low noise (low-RFI) environments (very important), and no front-end overload from strong local signals (often a problem in Europe from the powerful transmitters of international broadcasters). Here is a sample list of just a few of my favourite receivers:

• Brazil: http://177.20.168.179:8073/ Lots of receivers to choose from in Brazil, including this one operated by two local hams in the little inland town of Pardinho in the state of São Paulo. Running off a G5RV antenna, this receiver is ideal for monitoring domestic SW and MW Latin broadcasters.
• Finland: http://oh6bg.ddns.net:8073/ There are a number of good receivers in Finland, including this one made available by my friend Jari OH6BG (of VOACAP fame). Located right by the sea the site is also a working ham DX contest station, has an impressive array of antennas, and is in a low noise environment. Great for Europe, Asia and into South America.
• India: http://bengaluru.twrmon.net:8073/ There are several stations to choose from including this one operated by Trans World Radio. It has good ears for Asia.
• Netherlands: http://websdr.ewi.utwente.nl:8901/ I have already mentioned it above, but the SDR at the University of Twente is still one of the best receivers for checking out the European LW, MW and SW scene as well as further afield into Africa and the Middle East.
• New Zealand: http://kiwisdr.northlandradio.nz:8073/ If you are looking for some action in the Pacific, Northland Radio is one of the very best receivers for both SW, AM and ham listening! Low RFI, a good antenna and a fabulous location at the very top of New Zealand’s North Island ensures reception from across the Pacific, into Asia and the Americas. Part of a private maritime coast radio station (Callsign: ZMH292), so it occasionally suffers splatter QRM from its own transmissions on the maritime frequencies. Read about this unique station at https://northlandradio.nz/
• Qatar: http://midskiwi.ddns.net:8073/ This location is great for checking stations out of the Middle East while also useful for listening to Asia and Europe.
• Sweden: http://sm2byc.ddns.net:8073/ Owned by Mauritz SM2BYC, this receiver is great fun to operate if your interests lie in the mediumwave (AM) and longwave parts of the radio spectrum. The antenna switch (located under the Extension dropdown menu) offers three antennas and a choice of direction!

Of course, there are 90+ receivers in the US and 20+ in Canada. And there are many online receivers across Europe, including 75+ in Germany alone. From many points on the Earth, you can listen to remote receivers located in Russia, Japan, Vietnam, China, Indonesia, South Africa, Kuwait, and more. With around 650 receivers to choose from at the KiwiSDR website, there are bound to be many that you will enjoy discovering. Most of these radios, the costs of Internet access and streaming data charges are all self-funded. So you can show your appreciation to the owners of these receivers by voting for your favourites. Hopefully, this encourages them to remain online over the long term.

Whether you choose to continue with the so-called “real radios” or explore the exciting world of online SDRs, or be like me and make the most of a combination of these two options, the most important thing is that you enjoy this wonderful hobby!

73 and good DX to you all!

Rob Wagner VK3BVW

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© Rob Wagner, Mount Evelyn DX Report, and contributors 2012-2019