Tag Archives: SDR Spectrum Recordings

My Radio Spectrum Archive HOPE XII presentation on Hackaday

Wow! Thank you, Hackaday:

HOPE XII: TIME TRAVEL WITH SOFTWARE DEFINED RADIO

by: Tom Nardi

It’s easy to dismiss radio as little more than background noise while we drive. At worst you might even think it’s just another method for advertisers to peddle their wares. But in reality it’s a snapshot of the culture of a particular time and place; a record of what was in the news, what music was popular, what the weather was like, basically what life was like. If it was important enough to be worth the expense and complexity of broadcasting it on the radio, it’s probably worth keeping for future reference.

But radio is fleeting, a 24/7 stream of content that’s never exactly the same twice. Yet while we obsessively document music and video, nobody’s bothering to record radio. You can easily hop online and watch a TV show that originally aired 50 years ago, but good luck finding a recording of what your local radio station was broadcasting last week. All that information, that rich tapestry of life, is gone and there’s nothing we can do about it.

Or can we? At HOPE XII, Thomas Witherspoon gave a talk called “Creating a Radio Time Machine: Software-Defined Radios and Time-Shifted Recordings”, an overview of the work he’s been doing recording and cataloging the broadcast radio spectrum. He demonstrated how anyone can use low cost SDR hardware to record, and later play back, whole chunks of the AM and shortwave bands. Rather than an audio file containing a single radio station, the method he describes allows you to interactively tune in to different stations and explore the airwaves as if it were live.[…]

Continue reading the full article at Hackaday.

Don shares spectrum recordings from northern Peru

Many thanks to SWLing Post contributor, Don Moore, who writes:

I’ve been traveling through northern Peru and I’ve made some SDR recordings along the way – medium wave, long wave, and some shortwave meter bands. I hope to eventually get through them all!

I have also uploaded some recordings to a shared Google drive so that other DXers can hear what the bands sound like in northeastern Peru, on the edge of the Amazon jungle. Maybe some of the blog readers would be interested in this. You will need the below link to see the SDR files and an explanatory document. I plan to add a few more once I get another hotel with a good Internet connection again.

Click here to download.

Fantastic, Don!  Thank you for sharing your spectrum recordings!

Post readers: If you don’t already have HDSDR installed on your PC, you’ll need to grab it here. HDSDR is free and can playback these spectrum recordings. Once installed, simply press the “play” button on the HDSDR console and point HDSDR to the downloaded spectrum file. You’ll be tuning through Peruvian spectrum in no time!

Also, check out Don Moore’s excellent blog: http://www.donmooredxer.com 

Shortwave Archives, Spectrum Archives and the Radio Preservation Task Force meeting

This week, I’m looking forward to participating in the three day Radio Preservation Task Force meeting in Washington, DC.

The Radio Preservation Task Force (RPTF), a project of the National Recording Preservation Board of the Library of Congress, will be held on November 2nd, 3rd, and 4th, 2017 at the Library of Congress, Woodrow Wilson International Center for Scholars, and the University of Maryland.

I’ve been invited to serve on the RPTF Material & Digital Curation panel where I’ll have an opportunity to talk about our work with the Shortwave Radio Audio Archive and a new project I’ve been working on: the Radio Spectrum Archive.

The Radio Spectrum Archive

For several years, I’ve been championing the concept of archiving radio spectrum recordings.

As many of you know, through the use of software defined radios (SDRs), we can record not just one individual broadcast from one radio station at a time, but we can record an entire broadcast band, all at once. Each recording can easily contain dozens of stations broadcasting simultaneously. Later, via an SDR app, recordings can be tuned and listened to as if they were live. We believe spectrum recordings will be valuable material for the future historian, anthropologist, enthusiast, etc.

Screen shot of the RSA homepage.

I’ve published a new website for the Radio Spectrum Archive and I encourage you to check it out as it outlines our mission, goals and challenges. I also include a video demonstration using a spectrum recording from 1986 (originally recorded on a HiFi VCR!).

Note that the website is a work in progress, there are still sections to add including bios of our spectrum archive team.

Click here to check out the Radio Spectrum Archive website.

Though I didn’t mention this in my Patreon campaign post earlier this week, the Radio Spectrum Archive is yet another important radio project you are supporting with your pledge. This week, for example, extra funds help me with travel expenses associated with the RPTF conference (many thanks to a kind friend who is hosting me at his home for four nights, saving me several hundred dollars!).

If you have the means and would like to support the SWLing Post, the Shortwave Radio Index, the Shortwave Radio Audio Archive, and the Radio Spectrum Archive please use the link/button below to become a Patron. If you’d like more details or support options, check out this recent post.

Become a Patron!

And to all of you who have supported us through Patreon and with one time gifts: thank you, thank you, thank you!

If you’re not in a position to become a patron or coffee fund supporter, no worries! Just enjoy our radio sites and resources!

One more note: Due to travels and a heavy workload over the next couple of weeks, please allow extra time for replies to correspondence and comments. Thank you so much!

SDR Spectrum to Radio: Can someone please make this device?

The venerable RF switch box from the 1970s/80s allowed game consoles and computers to use analog TVs as monitors.

As I’ve mentioned in the past, I actively record and index radio spectrum recordings via my various software defined receivers. Indeed, I have at least 50 TB of SDR spectrum recordings at the moment–and that number is growing!

I was just chatting with SWLing Post contributor, Mark Fahey, and a familiar topic came up: the idea of an RF switch box for radios.

The concept is a piece of hardware that re-modulates–converts digital spectrum data from a digital storage device back to analog RF– and injects a signal into a real tabletop radio.

As Mark described:

“This is just like early computers and Atari-like games consoles did to allow the “computer” to display on a lounge room TV. The games console tricked the TV into thinking it was tuned to a TV station on “Channel 1 (or whatever the console outputted the video to).”

Radio time travel machine!

How cool would it be to take a spectrum recording from 2008, play it through your Hallicrafters SX-100, Kenwood R-1000 or Alinco DX-R8T, and tune through the 31 meter band? You’d receive Radio Australia, Radio Bulgaria, Radio Netherlands Worldwide, Radio Canada International, Voice of Russia and many other broadcasters that are no longer on the air. Indeed, there’s a strong possibility you might uncover DX you didn’t catch when the recording was first made.

I’m enough of a radio geek to know that I would thoroughly enjoy travelling back in time once in a while with a classic radio.

Additionally, this device would make it much easier for museums to create kiosks where visitors could tune through recordings of, say, important events in history.

Can it be done?

I know the technology is out there.  In fact, if you’ve ever been to a large hamfest where Icom, Yaesu or Kenwood have a number of their transceivers “on the air”–so customers can try out transceiver features–they are using a device called a “radio time machine.”

Icom uses recorded IF instead of live antenna input so customers can experience “contest conditions” while evaluating a radio.

The Radio Time Machine injects recorded analog RF, from a HiFi VCR, into the antenna ports of a vendor’s various transceivers. The recordings are typically of a ham radio band during a contest–that way, the customer can get a sense of how well the rig would perform under crowded band conditions.

These devices have limitations: while their bandwidth is ample to tune through the CW or phone portion of a ham band, it’s much too narrow for most broadcast bands. They’re also fed the recording from an analog HiFi VCR.

The device Mark and I dream of would convert digital spectrum files–from a WinRadio, Perseus, Elad, SDRplay, Airspy or other SDR–into analog RF any radio with an external antenna port could tune.

SWLing Post readers: you’re a diverse and knowledgeable community–please comment if you know what it would take to develop such a device and how it could be done. Is this a dream or could it become reality?