Category Archives: Software Defined Radio

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?

U Twente antenna damaged

Many thanks to SWLing Post contributor, Dan Robinson, who shares the following item from BCL News and Richard Langley:

Antenna of Twente SDR receiver damaged // Bclnews
http://www.bclnews.it/2017/10/06/antenna-of-twente-sdr-receiver-damaged/

The antenna was damaged yesterday during a storm. As posted on the WebSDR website:

“The antenna currently is not working properly. After a preliminary repair of rain/storm damage on October 5, it seems reception has faded away again during the night. We’ll try to fix this soon, weather and spare-time manpower permitting.”

(Richard Langley via dxld yg)

Radio Deals: HRO Superfest 2017 sale includes the SDRplay RSP2

I just received the following sale via an email from Ham Radio Outlet:

All of these are great prices, but I’m especially attracted to the SDRplay RSP2 for $139.95 and the CX-210N for $29.95.  If you’ve been on the fence about purchasing an RSP2, this is the lowest price I’ve seen for one.

Click here to view these deals at Ham Radio Outlet.

The GR-227: Gospell introduces a new SDR digital radio car adaptor

Many thanks to SWLing Post contributors Ed and Richard Langley for sharing information about the latest receiver from Gospell: the GR-227 digital radio car adaptor.

According to Radio World:

[…]The compact GR-227 can be added to car stereos, via a USB cable, in order to receive digital radio programs and corresponding data. Based on software-defined radio technology and using the xHE-AAC audio codec, the GR-227 is compatible with both modes of the Digital Radio Mondiale standard as well as the DAB/DAB+ digital radio standards.

According to Gospell, the GR-227 works with car stereos that are fitted with a USB port. Using the firm’s patent-pending technology, the adaptor behaves like a thumb drive when plugged into a USB port, making it compatible with most in-car receivers.

In addition, the GR-227 also features the Gospell Smart Tune App for Android. When partnered with an Android-powered car stereo, this lets users play back the broadcast audio program or benefit from data services.[…]

Read the full article at Radio World.

Richard comments:

“They call it an adaptor but perhaps it’s just an Android-controlled SDR receiver supplying audio output via a USB port, which could be connected to a computer or any other audio device with a USB audio input capability.”

I think he may be correct in that assumption because it may be the only way to get cross-manufacturer compatibility in a device like this.

The product information sheet noted that the receiver is supplied with a “triple band active antenna.” No doubt, the GR-227 will require adding a small external antenna to your car.

Still: an interesting product for sure! Perhaps the price point will be more reasonable that of previous DRM receivers? We’ll post updates from Gospell with the tag: GR-227

Servosila develops a robot with onboard SDR package

(Source: Servosila Press Release)

Servosila introduces a new member of the family of Servosila “Engineer” robots, a UGV called “Radio Engineer”. This new variant of the well-known backpack-transportable robot features a Software Defined Radio (SDR) payload module integrated into the robotic vehicle. Servosila introduces a new member of the family of Servosila “Engineer” robots, a UGV called “Radio Engineer”. This new variant of the well-known backpack-transportable robot features a Software Defined Radio (SDR) payload module integrated into the robotic vehicle.

“Several of our key customers had asked us to enable an Electronic Warfare (EW) or Cognitive Radio applications in our robots”, – says a spokesman for the company, “By integrating a Software Defined Radio (SDR) module into our robotic platforms we cater to both requirements. Radio spectrum analysis, radio signal detection, jamming, and radio relay are important features for EOD robots such as ours. Servosila continues to serve the customers by pushing the boundaries of what their Servosila robots can do. Our partners in the research world and academia shall also greatly benefit from the new functionality that gives them more means of achieving their research goals.”

Coupling a programmable mobile robot with a software-defined radio creates a powerful platform for developing innovative applications that mix mobility and artificial intelligence with modern radio technologies. The new robotic radio applications include localized frequency hopping pattern analysis, OFDM waveform recognition, outdoor signal triangulation, cognitive mesh networking, automatic area search for radio emitters, passive or active mobile robotic radars, mobile base stations, mobile radio scanners, and many others.

A rotating head of the robot with mounts for external antennae acts as a pan-and-tilt device thus enabling various scanning and tracking applications. The neck of the robotic head is equipped with a pair of highly accurate Servosila-made servos with a pointing precision of 3.0 angular minutes. This means that the robot can point its antennae with an unprecedented accuracy.

Researchers and academia can benefit from the platform’s support for GnuRadio, an open source software framework for developing SDR applications. An on-board Intel i7 computer capable of executing OpenCL code, is internally connected to the SDR payload module. This makes it possible to execute most existing GnuRadio applications directly on the robot’s on-board computer. Other sensors of the robot such as a GPS sensor, an IMU or a thermal vision camera contribute into sensor fusion algorithms.

Since Servosila “Engineer” mobile robots are primarily designed for outdoor use, the SDR module is fully enclosed into a hardened body of the robot which provides protection in case of dust, rain, snow or impacts with obstacles while the robot is on the move. The robot and its SDR payload module are both powered by an on-board battery thus making the entire robotic radio platform independent of external power supplies.

Servosila plans to start shipping the SDR-equipped robots to international customers in October, 2017.

Web: https://www.servosila.com

YouTube: https://www.youtube.com/user/servosila/videos

About the Company

Servosila is a robotics technology company that designs, produces and markets a range of mobile robots, robotic arms, servo drives, harmonic reduction gears, robotic control systems as well as software packages that make the robots intelligent. Servosila provides consulting, training and operations support services to various customers around the world. The company markets its products and services directly or through a network of partners who provide tailored and localized services that meet specific procurement, support or operational needs.