Tag Archives: Diversity Reception

Ham Radio Workbench episode explores Diversity Reception

The SDRplay RSPduo

I just finished listening to the most recent episode of the Ham Radio Workbench with John Fallows (VE6EY) as a guest.

John is an SWL and Ham Radio operator and speaks at length about how he uses diversity reception to mitigate persistent local RFI (radio frequency interference).

If you have persistent issues with radio interference or if you’ve been curious about using diversity reception for mediumwave and shortwave DXing, I highly recommend listening to this episode. John has been known to frequent the SWLing Post and actually comes into the discussion primarily from an SWL’s perspective.

If you’ve tried diversity reception or a noise-cancelling system like the Timewave ANC-4+ in the past with mixed results, you’ll definitely benefit from listening to John’s best practices.

In addition, John points out that the excellent SDRplay RSPduo is a very affordable way to explore proper diversity reception.

How effectively can you mitigate RFI with diversity reception? Check out this video on YouTube queued up to the point where John does a live demo with his Anan SDR and loop antennas: https://youtu.be/vu8D87aVUTQ?t=2011 (I also recommend watching to full video presentation for even more detail.)

I’ve embedded the audio for the Ham Radio Workbench podcast below, but you can also find it along with show notes on the Ham Radio Workbench website.

Ham Radio Workbench is one of my favorite podcasts; if you like exploring a wide variety of technical topics, I highly recommend checking it out. It’s available on all podcasting platforms.

Also, check out John VE6EY’s YouTube channel and web site/blog.

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SDRplay RSPduo: SDRuno update now adds diversity reception!

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The SDRplay RSPduo

Many thanks to Andy with SDRplay who notes:

We are pleased to announce the release of v1.32 of SDRuno. The purpose of this release is primarily to add MRC Diversity functionality for the RSPduo, but it also contains other fixes and additions based on customer feedback. Diversity functionality is described on P.78 of the SDRuno User Manual.

A full list of the changes can be found in the release notes: https://www.sdrplay.com/docs/SDRplay_SDRuno_Release_Notes.pdf

Issues can be reported to us via our ticket system: https://www.sdrplay.com/support

Comments and feedback can be sent to [email protected] – emails sent to that address are usually not responded to unless we have questions, but are always read and noted.

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Hamvention Highlights: Affordable diversity reception with the SDRplay RSPduo

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Each year at the Dayton Hamvention I enjoy checking out the latest radio products and services. This year (2019) I found an exceptional number of innovations and will share these in Hamvention Highlights posts. If you would like to check out 2019 Hamvention Highlights as I publish them, bookmark this tag: 2019 Hamvention Highlights

Diversity reception with the SDRplay RSPduo

Last year, during the 2018 Hamvention, SDRplay announced the RSPduo, a 14bit dual-tuner SDR. We posted a review of the RSPduo on the SWLing Post.

At the time, SDRplay mentioned that the RSPduo could eventually be used for diversity reception.

Diversity reception is the ability to combine or select two signals, from two (or more) antenna sources, that have been modulated with identical information-bearing signals, but which may vary in their fading/noise characteristics at any given instant.

In short, diversity reception gives one a powerful tool to mitigate fading and noise, and to improve a signal’s overall integrity.

Andy and Mike with SDRplay demonstrated SDRuno’s diversity reception functionality and noted that it will soon roll out as a free upgrade to SDRuno, SDRplay’s open SDR application.

I should note here that the SDRplay booth at the 2019 Hamvention was incredibly busy—no doubt, because the RSPduo must be one of the least expensive, most accessible, ways to experiment with diversity reception. Case in point: the new Elecraft K4D transceiver will support diversity reception, but the price is about $4,700 US; the RSPduo can be purchased for $280 US.

Based on the demonstration, this feature will be quite easy to use and I love how it has been implemented in the SDRuno GUI (graphical user interface).

To learn more about the RSPduo, check out SDRplay’s website or read our review. Of course, when SDRplay releases the diversity reception upgrade to SDRuno, we will make an announcement!

If you would like to follow other Hamvention Highlights, bookmark the tag: 2019 Hamvention Highlights

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On shortwave radio diversity reception

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Many thanks to SWLing Post contributor, London Shortwave, who recently shared this post from the blog, Making It Up:

Shortwave Radio Diversity Reception

Shortwave radio diversity reception provides a way to combine several fluctuating signals and get a solid result. It provided the foundation for most radio news received in America for years.

During World War II, most countries around the world relied on Britain’s shortwave radio broadcasts for the latest news from Europe. In the days before transatlantic audio cables or satellites, distant news traveled fastest by radio. Networks in the America’s, Australia, New Zealand and elsewhere re-broadcast shortwave radio news domestically.

Getting reliable, good quality audio programs over shortwave is always a challenge because of fading. As signals bounce off the ionosphere, they split over multiple paths. Often they fade and flutter, sometimes significantly, as the nature of the layers change with time. Here are several examples of shortwave signals fading, so you know what it sounds like. Skywave radio signals are subject to complex patterns of travel and interference.

Eventually, domestic networks found a clever way to get better audio from these distant signals.

[…]Diversity reception works like this. Instead of one signal, you monitor several signals at once and blend them together. Harold Beverage and RCA pioneered work on shortwave radio diversity reception in 1920’s. Commercial solutions arrived by 1933. Typically, you would use three receivers with three different antennas, spaced 1,000 feet apart. When antennas are widely spaced, signals arrive with different fading. Just combine the signals and let the strongest signal dominate. As long as the fading is not correlated across all three antennas, improvement can be significant.

Diversity reception can be achieved in several ways. The most popular – spatial diversity – is described above. Other methods include frequency diversity – mixing together the same program received on several different channels.[…]

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