Tag Archives: Hackaday

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.

Thai cave rescue employed ham-designed 87 kHz transceiver

(Source: Hackaday via bernieS)

Unless you live in a cave, you’ve probably heard a little about the thirteen people — mostly children — trapped in the Tham Luang Nang Non cave in Thailand. What you may have missed, though, is the hacker/ham radio connection. The British Cave Rescue Council (BCRC) was asked for their expert help. [Rick Stanton], [John Volanthen] and [Rob Harper] answered the call. They were equipped with HeyPhones. The HeyPhone is a 17-year-old design from [John Hey, G3TDZ]. Sadly, [G3TDZ] is now a silent key (ham radio parlance for deceased) so he didn’t get to see his design play a role in this high-profile rescue, although it has apparently been a part of many others in the past.

The HeyPhone is actually considered obsolete but is still in service with some teams. The radio uses USB (upper sideband, not universal serial bus) at 87 kHz. The low frequency can penetrate deep into the ground using either induction loop antennas like the older Molephone, or — more commonly — with electrodes injecting RF energy directly into the ground.

You can find a very detailed article about the radio from 2001 if you want more details. The system is somewhat dated, but apparently works well and that’s what counts.[…]

Click here to read the full article at Hackaday.

Google’s 96.4 kilowatt experimental transmitter

spaceport-virgin

Many thanks to SWLing Post contributor, Dan Robinson, for sharing the following story:

(Source: Hackaday)

[…]In a publication released last week, Google asked the FCC to treat some information relating to radio experiments as confidential. These experiments involve highly directional and therefore high power [96.4 kilowatt] transmissions at 2.5 GHz, 5.8GHz, 24GHz, 71-76GHz, and 81-86GHz. These experiments will take place at Spaceport America, a 12,000 foot runway in the middle of New Mexico occasionally used by SpaceX, Virgin Galactic, and now Google.

For the most part, this document only tells the FCC that Google won’t be causing harmful interference in their radio experiments. There few other details, save for what bands and transmitters Google will be using and an experimental radio license call sign (WI9XZE) that doesn’t show up in the FCC database.[…]

Read the full article at Hackaday…

Click here to read FCC File No. 0142-EX-PL-2016 (Google Public Redacted Version).

Jagadish Chandra Bose and the invention of radio

Jagadish Chandra Bose in Royal Institution, London

Jagadish Chandra Bose in Royal Institution, London

Many thanks to SWLing Post reader, A Black, for sharing the following article from the excellent Hackaday blog:

J.C. BOSE AND THE INVENTION OF RADIO

The early days of electricity appear to have been a cutthroat time. While academics were busy uncovering the mysteries of electromagnetism, bands of entrepreneurs were waiting to pounce on the pure science and engineer solutions to problems that didn’t even exist yet, but could no doubt turn into profitable ventures. We’ve all heard of the epic battles between Edison and Tesla and Westinghouse, and even with the benefit of more than a century of hindsight it’s hard to tell who did what to whom. But another conflict was brewing at the turn of 19th century, this time between an Indian polymath and an Italian nobleman, and it would determine who got credit for laying the foundations for the key technology of the 20th century – radio.

Appointment and Disappointment

In 1885, a 27-year old Jagadish Chandra Bose returned to his native India from England, where he had been studying natural science at Cambridge. Originally sent there to study medicine, Bose had withdrawn due to ill-health exacerbated by the disagreeable aroma of the dissection rooms. Instead, Bose returned with a collection of degrees in multiple disciplines and a letter of introduction that prompted the Viceroy of India to request an appointment for him at Presidency College in Kolkata (Calcutta). One did not refuse a viceroy’s request, and despite protests by the college administration, Bose was appointed professor of physics.

Click here to continue reading on Hackaday…