Tag Archives: Linux

Radio Waves: Shively Labs Broadcast Antennas, Fedora SWL, F-150 Lightning AM, and Young Listeners on the Decline

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Radio Waves:  Stories Making Waves in the World of Radio

Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributor Dennis Dura for the following tips:

Public radio engineers await fate of major antenna maker (Current)

The potential sale of one of the country’s only major manufacturers of high-power FM broadcast antennas is causing concern among public radio engineers who have long depended on the company for challenging projects such as directional antennas and multistation combiner systems.

Antennas and combiners made by Shively Labs carry the signals of many major stations, from Boston’s WBUR to Dallas’ KERA/KXT to Seattle’s KUOW. Shively’s headquarters in Maine boasts one of the few test ranges needed to fully prepare complex directional antenna systems for real-world performance.

Founded in 1963 by former RCA engineer Ed Shively, the company has been owned since 1980 by Howell Laboratories, an engineering firm that now has a wide range of product lines. Those include water purification systems, dehydrators and an increasing amount of contract work for the U.S. Navy.

While its military and commercial marine business has grown, broadcast antennas have become a smaller piece of the company’s portfolio, said Shively VP Angela Gillespie. [Continue reading…]

How to become a Shortwave listener (SWL) with Fedora Linux and Software Defined Radio (Fedora Magazine)

Catching signals from others is how we have started communicating as human beings. It all started, of course, with our vocal cords. Then we moved to smoke signals for long-distance communication. At some point, we discovered radio waves and are still using them for contact. This article will describe how you can tune in using Fedora Linux and an SDR dongle.

My journey

I got interested in radio communication as a hobby when I was a kid, while my local club, LZ2KRS, was still a thing. I was so excited to be able to listen and communicate with people worldwide. It opened a whole new world for me. I was living in a communist country back then and this was a way to escape just for a bit. It also taught me about ethics and technology.

Year after year my hobby grew and now, in the Internet era with all the cool devices you can use, it’s getting even more exciting. So I want to show you how to do it with Fedora Linux and a hardware dongle. [Continue reading…]

Did AM Radio Just Get Hit By “Lightning”? (Radio World)

There’s something missing from the newest F-150 Lightning truck

These days, the auto industry is as disrupted as broadcast radio. Like the radio companies – a group of independent operators, each moving down a different pathway – automakers are highly individual companies. Continue reading →

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Looking for Linux Mini PC recommendations

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Mintbox Mini

Even though I do most of my blogging from a MacBook Air and use a Windows 10 PC in the shack for SDR work, I’m a huge fan of Linux.

Over the past decade, I’ve used a number of Linux distributions including Puppy Linux, Ubuntu, Linux Mint, and Raspian.

The past few years, I’ve been doing most of my Linux work with a Raspberry Pi running Raspian. I probably own ten or more Raspberry Pi models; some have one dedicated task (like the Raspberry Pirate, my ADS-B feeder, or one that feeds LiveATC) while others, like the Pi4 4GB models, are serving as primary personal computers for my daughters. I’ve been trying to up my command line game so I can continue teaching it to my daughters–the Pi has been perfect for this.

Why a mini PC?

While I love the Raspberry Pi, I would like a dedicated device in the shack that sports more horsepower and a better integrated sound card. I also want something compact.

In the past, I have, of course, resurrected old PCs by installing Linux and I’ve even turned my primary shack PC into a Windows/Linux dual boot system. I’m not the biggest fan of dual boot, though, because I have run into problems when I needed to do a full re-install of Windows and/or Linux–all of that partition management gets tricky for me. I’ve even found a few PCs (guessing it’s the BIOS) that reject the dual boot loading system.

I simply don’t have the desktop real estate for another revived desktop or tower PC.

Spoiled for choice

I like the idea of a Mini PC dedicated to Linux but there are a dizzying array of devices on the market ranging in price from $100-$700. I don’t need a lot of horsepower, just enough to run SDR apps, potentially playback spectrum recordings, stream videos, and occasionally manipulate graphics and images. The Pi can do many of these tasks to an extent, but it’s not always terribly stable.

I’ve been tempted by this mini PC because the reviews seem positive (although I don’t always trust Amazon reviews) and the price is right at $129.

The Lenovo ThinkCentre M90n IoT

I’ve also read positive comments from folks who’ve loaded Ubuntu on a base version of the Lenovo ThinkCentre M90n IoT.

Of course, I know I can also buy Mini PCs that have Linux pre-loaded and part of the proceeds support development of the distro like the Mintbox Mini pictured at the top of this page. I do like the idea of my purchase directly supporting the distro.

I also like the Intel NUC, but once configured it can be a bit pricey for my purposes. I don’t want to exceed $300.

Any recommendations?

If you have any advice, I’m all ears! I’m especially interested in any first-hand experience with a Mini PC model running Linux. Please feel free to comment with your suggestions and links.

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Radio Waves: The Future of On-Air DJs, SDR Comparison, Radios That Never Were, and an Internet Radio Player for Linux

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Radio Waves:  Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers.  To that end: Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Jack Kratoville, Dave Zantow, and Dennis Dura for the following tips:

Live From Everywhere? The American Radio DJ In An On-Demand World (1A)

iHeartMedia owns and operates 858 broadcast radio stations, serving more than 150 markets throughout the U.S. The company reaches over a quarter billion monthly listeners ?in America.

In January, news hit that iHeartMedia was reassessing its ability to adapt to the modern music industry. The company said that it plans to make “significant investments … in technology and artificial intelligence.”

However, its on-air DJs were caught off guard when they found out that the company’s restructuring plan didn’t include them.

Streaming platforms has ushered in the digital age of music where each person make their own playlists. What does that mean for the future of the on-air DJ in the United States?

Click here to listen to the audio.

A comprehensive lab comparison between multiple software defined radios (RTL-SDR.com)

Librespace, who are the people behind the open hardware/source SatNOGS satellite ground station project have recently released a comprehensive paper (pdf) that compares multiple software defined radios available on the market in a realistic laboratory based signal environment. The testing was performed by Alexandru Csete (@csete) who is the programmer behind GQRX and Gpredict and Sheila Christiansen (@astro_sheila) who is a Space Systems Engineer at Alexandru’s company AC Satcom. Their goal was to evaluate multiple SDRs for use in SatNOGS ground stations and other satellite receiving applications.

The SDRs tested include the RTL-SDR Blog V3, Airspy Mini, SDRplay RSPduo, LimeSDR Mini, BladeRF 2.0 Micro, Ettus USRP B210 and the PlutoSDR. In their tests they measure the noise figure, dynamic range, RX/TX spectral purity, TX power output and transmitter modulation error ratio of each SDR in various satellite bands from VHF to C-band.

The paper is an excellent read, however the results are summarized below. In terms of noise figure, the SDRplay RSPduo with it’s built in LNA performed the best, with all other SDRs apart from the LimeSDR being similar. The LimeSDR had the worst noise figure by a large margin.[…]

Radios that Never Were (N9EWO)

Dave Zantow (N9EWO) shares a new page on his website devoted to receivers and amateur transceivers that never quite made it to the marketplace. […]

Shortwave: A Modern Internet Radio Player for Linux (It’s Floss)

Brief: Shortwave is a modern looking open source Internet Radio player for Linux desktop. We take a quick look at it after its recent stable release.

Shortwave is an interesting open-source radio player that offers a good-looking user interface along with a great experience listening to the Internet stations. It utilizes a community-powered database for the Internet stations it lists.

Shortwave is actually a successor of the popular radio app for Linux, Gradio. Its developer Felix joined GNOME and discontinued Gradio to create Shortwave from scratch in Rust programming language. If you were using Gradio as your preferred Internet radio station player, you can import the library as well.

Recently, Shortwave released its first stable version and seems to push new updates after that as well.[…]

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Tudor demos his portable Raspberry Pi-powered AirSpy HF+

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Many thanks to SWLing Post contributor, Tudor Vedeanu, who has kindly shared details about his portable Raspberry Pi system which now can run the AirSpy HF+ SDR.

Tudor writes:

I bought the RPi to use it as a Spyserver for my Airspy HF+ SDR.

My main radio listening location is a small house located on a hill outside the city and there is no power grid there (it’s a radio heaven!), so everything has to run on batteries and consume as little power as possible.

My first tests showed that the Raspberry Pi works very well as a Spyserver: the CPU usage stays below 40% and the power consumption is low enough to allow it to run for several hours on a regular USB power bank. If I add a 4G internet connection there I could leave the Spyserver running and connect to it remotely from home.

Then I wondered if the Raspberry Pi would be powerful enough to run a SDR client app. All I needed was a portable screen so I bought the official 7” touchscreen for the RPi.

I installed Gqrx, which offers support for the Airspy HF+. I’m happy to say it works better than I expected, even though Gqrx wasn’t designed to work on such a small screen. The CPU usage is higher than in Spyserver mode (70-80%) but the performance is good. Using a 13000 mAh power bank I get about 3.5 hours of radio listening.

I made a video showing how it works:

Click here to view on YouTube.

This is fantastic, Tudor. Thanks for taking the time to put together a video for us. I’ve just ordered the latest Raspberry Pi 3 (Model B+). It has slightly more horsepower than the previous Pi3. Tudor, you’ve inspired me to grab the 7″ touch display as well and try my hand at running the AirSpy HF+ portable.

I’m not sure if the Raspberry Pi 3 will be able to record spectrum without hiccups, but it’s certainly worth a try.

As you tweak your system, please keep us in the loop!

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