Radio

Where There's No Distance or Gravity

Doc Searls — Tue, 15 Jan 2019 13:00:00 +0000

The more digital we become, the less human we remain.

I had been in Los Angeles only a few times in my life before the October day in 1987 when I drove down from our home in the Bay Area with my teenage son to visit family. The air was unusually clear as we started our drive back north, and soon the San Gabriel Mountains—Los Angeles' own Alps (you can ski there!)—loomed over the region like a crenelated battlement, as if protecting its inhabitants from cultures and climates that might invade from the north. So, on impulse, I decided to drive up to Mount Wilson, the only crest in the range with a paved road to the top.

I could see from the maps I had already studied that the drive was an easy one. Our destination also was easily spotted from below: a long, almost flat ridge topped by the white domes of Mount Wilson Observatory (where Hubble observed the universe expanding) and a bristle of towers radiating nearly all the area's FM and TV signals. The site was legendary among broadcast engineering geeks, and I had longed to visit it ever since I was a ham radio operator as a boy in New Jersey.

After checking out the observatory and the towers, my son and I stood on a promontory next to a parking lot and surveyed the vast spread of civilization below. Soon four visiting golfers from New York came over and started asking me questions about what was where.

I answered like a veteran docent, pointing out the Rose Bowl, Palos Verdes Peninsula, Santa Catalina and other Channel Islands, the Hollywood Hills, the San Fernando Valley, the Jet Propulsion Laboratory, Santa Anita Park and more. When they asked where the Whittier Narrows earthquake had happened a few days before, I pointed at the Puente Hills, off to the southeast, and filled them in on what I knew about the geology there as well.

After a few minutes of this, they asked me how long I had lived there. I said all this stuff was almost as new to me as it was to them. "Then how do you know so much about it?", they asked. I told them I had studied maps of the area and refreshed my knowledge over lunch just before driving up there. They were flabbergasted. "Really?", one guy said. "You study maps?"

Indeed, I did. I had maps of all kinds and sizes at home, and the door pockets of my car bulged with AAA maps of everywhere I might drive in California. I also added local and regional Southern California maps to my mobile inventory before driving down.

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Creating an Internet Radio Station with Icecast and Liquidsoap

Bill Dengler — Mon, 15 Jan 2018 14:34:13 +0000

by Bill Dengler

Ever wanted to stream prerecorded music or a live event, such as a lecture or concert for an internet audience? With Icecast and Liquidsoap, you can set up a full-featured, flexible internet radio station using free software and open standards.

Icecast is "a streaming media (audio/video) server that currently supports Ogg (Vorbis and Theora), Opus, WebM and MP3 streams. It can be used to create an internet radio station or a privately running jukebox and many things in between. It is very versatile in that new formats can be added relatively easily and supports open standards for communication and interaction."

Liquidsoap is "a powerful and flexible language for describing your streams. It offers a rich collection of operators that you can combine at will, giving you more power than you need for creating or transforming streams. But Liquidsoap is still very light and easy to use, in the UNIX tradition of simple strong components working together."

When combined, Icecast and Liquidsoap can create a flexible, feature-rich internet radio station. In this article, I describe how to configure Icecast to host an internet radio station. Then, I explain how to install and configure Liquidsoap to connect to Icecast, adding random (or sequential) music playback with smart cross-fading, prerecorded randomly inserted announcements and jingles, a song request system and support for live streams, with automated recording and seamless switching between live and automated programming. I also show how to configure the server to serve your stream in MP3, Ogg and Opus formats for maximum player compatibility.

Icecast, Vorbis and related projects are maintained by Xiph.Org, a nonprofit organization that develops open multimedia standards and software. To ensure that you are running the latest version of Icecast, with all (or most) features, you should install from an official Xiph.Org repository. Visit the list of official repositories here, and follow the instructions on that page to add the Icecast repository for your distribution. Then, install using your system's package manager. On Debian-based systems (such as Ubuntu), you may be asked to "configure Icecast" during package installation; select "no" as you will configure the server manually if you are following along with this article.

Open the Icecast configuration file using your preferred text editor. On Debian-based systems, the file is located at /etc/icecast2/icecast.xml. The location on other systems may differ; check your package's documentation for the correct path. The configuration file is in XML format and is divided into several sections. First, enter your server's location and email into the location and admin fields, respectively—for example:

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Radio Free Linux

Alan Peterson — Tue, 22 Nov 2016 11:24:52 +0000

by Alan Peterson

You would have a difficult time today finding a radio station that was all-live and did not have some kind of computerized, automated means of storing and playing audio.

In a bygone era, hands-on media management of records and tape cartridges ("carts") was the way of the world. Through the years, turntables, CD players and "cart decks" gave way to mechanized playback of content by banks of reel-to-reel machines under crude sequential control. The earliest fully computerized "audio on hard drive" systems for radio stations and networks ran generally under DOS, evolving into the elaborate Windows-based systems in use everywhere today.

So What about Linux?

Do a web search for "Linux radio station", and the pickings are slim indeed, with most sites promoting instead ham radio software or streaming audio players, and a handful devoted to setting up a streaming web radio station—including one such optimistic article in Linux Journal some 15 years ago (see "Running a Net Radio Station with Open-Source Software", January 2001).

Unfortunately, much of this documented interest took place a decade or more in the past via domains like opensourceradio.com that are no longer with us. A few projects persevere, but a good number of postings are similarly dated. The fact is, there are more Linux-based ways to stream and listen to radio stations than there actually are the means to broadcast and control them.

Fortunately, the choices today are getting better. Transmitter manufacturer Nautel incorporates Linux in its AUI. Broadcast automation and media management systems, such as Airtime and DIY-DJ, were designed around Linux from the start. Many Windows-based commercial automation systems seem happy when networked with Linux servers. But, as for in-studio hands-on control of program execution, there still is a way to go.

Off to Washington

In and around the nation's capital, actual over-the-air radio programming driven by Penguin power is a reality, and you already may be listening to it wherever you are.

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Epiq Solutions' Sidekiq M.2

James Gray — Mon, 26 Sep 2016 11:00:00 +0000

by James Gray

Following on its resounding success with its Sidekiq MiniPCIe card, wireless communications systems specialist Epiq Solutions recently added the Sidekiq M.2 state-of-the-art, small form-factor, software-defined radio (SDR) card. Epiq Solutions explains that the Sidekiq product line provides a breakthrough small form-factor SDR transceiver solution ready for integration into systems that support either MiniPCIe or now the M.2 card form factors.

Compared to the Sidekiq MiniPCIe card, this next-generation product provides benefits such as a 20% size reduction, double the data throughput with its Gen2 PCIe interface, full 2x2 MIMO RF interface and increased FPGA resources with a Xilinx Artix-7 FPGA. Other features of the Sidekiq M.2 card include RF tuning range of 70MHz to 6GHz, up to 50MHz RF bandwidth per channel, flexible RF front end supporting two operating modes, 2.1 W typical power consumption and PDK including software API and FPGA source code.

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