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 Ron, Rich Cuff, and the Southgate ARC for the following tips:

Radio Amateur’s Vintage Home Movie Film Sheds Light on Hindenburg Disaster (ARRL News)

Vintage home movie film provided by New Jersey radio amateur Bob Schenck, N2OO, was the highlight of a PBS documentary about the Hindenburg disaster. The film, shot by his uncle Harold Schenck, may provide clues as to what initiated the disastrous 1937 fire that destroyed the airship Hindenburg and claimed 35 lives as the German zeppelin was landing at Lakehurst, New Jersey. Harold Schenck tried to interest government investigators in his film, shot from a different angle than newsreel footage that begins only after the fire was well under way, but it was largely overlooked. “Nobody ever asked for it,” Bob Schenck explains in the documentary.

The Schenck film is the highlight of a PBS “NOVA” documentary, Hindenburg: The New Evidence, that investigates the issue in considerable depth in an effort to unlock the secrets of the cold case. The program aired on May 19 and remains available for streaming.

“My dad had bought this nifty Kodak camera — a wind-up movie camera, 8 millimeters — and he couldn’t come [to the Hindenburg landing] because he worked,” Bob Schenck recounted during the documentary. “So, he asked my uncle and my mom if they would take some shots and see the Hindenburg land.”

Bob Schenck approached Dan Grossman, an expert on airships, including Hindenburg, in 2012 during a commemoration of the disaster that forever memorialized radio reporter Herbert Morrison’s plaintive on-air reaction, “Oh, the humanity!” The NOVA documentary not only shares Schenck’s footage, which provided new clues to re-examine the cause of the explosion. The documentary also reviews scientific experiments that helped investigators come to a fresh understanding of what set off the fire. [Continue reading…]

Will chip shortage hit ham radios ? (Southgate ARC)

Glenn O’Donnell K3PP of Forrester Research notes the chip shortage may have a more serious impact than first thought and gives Amateur Radio rigs as an example of what might be affected

Self-described as a “ham radio nut,” O’Donnell discussed one of his hobbies to explain how the sway of tech titans could impact smaller companies as industries compete for limited resources.

“In this hobby, the newer radio “toys” are advanced technology, but the hottest radio might sell 5,000 units per year. If Apple wants 100 million chips, but the little ham radio company wants 5,000, Apple wins!” O’Donnell said.

Read the article at
https://www.techrepublic.com/article/global-chip-shortage-the-logjam-is-holding-up-more-than-laptops-and-cars-and-could-spoil-the-holidays/

NPR at 50: A Highly Selective History (Washington Post)

The network’s half-century evolution from an audio experiment to a media powerhouse

Today NPR is one of Washington’s most familiar and influential media companies, operating out of a gleaming, ultramodern broadcast facility on North Capitol Street. Its radio programs, online content, and podcasts reach millions of people around the world. But when it launched 50 years ago, in April 1971, National Public Radio was a decidedly scrappy enterprise.

How did a modest radio project from a bunch of audio idealists evolve into the multimedia behemoth that we now spend countless hours listening to? To celebrate NPR’s anniversary, we’ve put together a look at its history and transformation. Please note: If you would like to imagine the whole thing being read to you in the voices of Nina Totenberg and Robert Siegel, we won’t object. Click here to read the full article…

SAQ Grimeton Transmission on July 4th (Southgate ARC)

The annual transmission event on the Alexanderson Day with the Alexanderson Alternator from 1924, on VLF 17.2 kHz CW with the call sign SAQ, is scheduled for Sunday, July 4th, 2021.

The Alexander Grimeton Association are planning to carry out two broadcasts to the world from the old Alexanderson alternator SAQ. Only required staff will be in place, due to the ongoing pandemic.

Transmission schedule:

Startup and tuning at 10:30 CET (08:30 UTC) with a transmission of a message at 11:00 CET (09:00 UTC)
Startup and tuning at 13:30 CET (11:30 UTC) with a transmission of a message at 14:00 CET (12:00 UTC)

Live Video from World Heritage Grimeton Radio Station
Both transmission events can be seen live on our YouTube Channel.
The live video starts 5 minutes before the startup and tuning.
https://mailchi.mp/aff85163e64f/alexanderson-day-2021?e=2c0cbe870f

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Engineers devise two-way radio on a single chip

Two-way communication requires, of course, both send and receive capabilities. But putting them in the same device requires a filter between the send and receive circuits to provide signal isolation.

Without a significant filter, communication would be impossible.

“Your transmit signal is [10 to the power 14] times stronger than your receive signal,” said Alyosha Molnar, associate professor of electrical and computer engineering (ECE). “That’s 100 trillion times stronger – that’s a really hard problem.”

But researchers in Molnar’s lab have offered up a solution.

Molnar and collaborator Alyssa Apsel, professor of ECE, have devised a method for both transmitting and receiving a radio signal on a single chip, which ultimately could help change the way wireless communication is done.

Their work is described in “A wideband fully integrated software-defined transceiver for FDD and TDD operation,” published online Jan. 27 in the Institute of Electrical and Electronics Engineers’ Journal of Solid-State Circuits. Doctoral student Hazal Yüksel and Dong Yang, Ph.D. ’15, are co-lead authors.

Separating the send and receive bands is difficult enough, but the problem is compounded by the ever-increasing number of bands in the latest devices. From GPS to Bluetooth to Wi-Fi, each band requires a filter to stop the strong transmit signals from drowning out reception.

Molnar and Apsel have come up with an ingenious way to separate the signals. Their idea lies in the transmitter – actually a series of six subtransmitters all hooked into an artificial transmission line. Each sends its signal at regular intervals, and their individually weighted outputs are programmed so that they combine to produce a radio frequency signal in the forward direction, at the antenna port, while canceling out at the receive port.

The programmability of the individual outputs allows this simultaneous summation and cancellation to be tuned across a wide range of frequencies, and to adjust to signal strength at the antenna.

“In one direction, it’s a filter and you basically get this cancellation,” Apsel said. “And in the other direction, it’s an amplifier.”

“You put the antenna at one end and the amplified signal goes out the antenna, and you put the receiver at the other end and that’s where the nulling happens,” Molnar said. “Your receiver sees the antenna through this wire, the transmission line, but it doesn’t see the transmit signal because it’s canceling itself out at that end.” […]