Radio Waves: Stories Making Waves in the World of Radio
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 Rich Dalton and Dennis Dura for the following tips:
The JacoBLOG Junk Drawer – The AM Radio Edition (Jacobs Media Strategies)
Is there a bigger buzzkill blog topic than AM radio?
In a an era where digital has transformed radio broadcasting’s content and revenue focus, the last thing anyone wants to talk about in 2023 is lowly AM radio. But like that old drunk uncle who shows up at the reunion, AM is still part of the radio family.
In its heyday, AM ruled the radio roost. It wasn’t until the late 70’s when FM surpassed AM in total listening, and later profitability. Before then, AM was the behemoth. And the biggest and best in class could be magically heard in dozens of states each night. Weather, atmospherics, and bodies of water all factored into AM reception.
Many Baby Boomers vividly recall laying in bed at night, precariously tuning in a faraway AM station carrying a ballgame or even broadcasting progressive music. Or grabbing a portable transistor radio – like the one sitting in our junk drawer – taking it to a sporting event and having a great audio soundtrack from legends like Vin Scully, Ernie Harwell, or Jack Buck. [Continue reading…]
Former FEMA Leaders Continue Push for AM Preservation (Radio World)
Say the removal of AM radios from cars is “a grave threat to future local, state and federal disaster response and relief efforts”
The laundry list of current and former government officials advocating for the safeguarding of AM radio in electric vehicles continues to grow.
On Feb. 26, seven former leaders of the Federal Emergency Management Agency penned a letter to Secretary Pete Buttigieg of the Department of Transportation advocating for the preservation of the senior band and urging regulators to take action to protect the nation’s public safety.
“Because of the great distances that its signal carries, and due to its resiliency during even the worst natural disasters, the success of the National Public Warning System hinges on the use of AM radio,” the collective of former FEMA leaders wrote. “However, should EV makers continue removing AM radios from their vehicles, this vital public safety system will no longer function as intended.”
The dialogue between automakers and AM advocates has grown signficiantly in recent weeks. As we reported earlier, the Alliance for Automotive Innovation sent a reply to Sen. Ed Markey after he asked individual car companies about their commitment to broadcast AM radio in electric and other future vehicles. In the days following, Markey, the alliance, the National Association of Broadcasters and, now, FEMA officials and and an FCC commissioner have continued a public discourse.[Continue reading…]
AM Devitalization (All Access)
Been to a shopping mall lately?
It’s not pretty. Vacancies dot even the most successful malls. The lesser malls feel abandoned, like modern ruins, isolated and scary. One mall near us is so barren, they’ve marked off part of one end and use it for pickleball. Even the mall walkers are gone. If a mall can’t draw mall walkers in South Florida, that’s a harbinger of doom.
The reasons that big indoor malls aren’t thriving anymore aren’t a secret. Habits changed. Tastes changed. People shop online now, or go to discounters like Walmart or Target. Department stores have fallen out of favor. Teens don’t hang out in the food court anymore; they’re congregating on TikTok. What’s left are traditionalist shoppers who want to try stuff on or handle it before buying, or people who want to see stuff in person before firing up the Amazon app and buying it there. Other than Apple stores and a few other chains with loyal customers, there’s not a lot to draw people to the mall anymore, and what’s left is kinda creepy. Some malls are now mostly occupied by local businesses trying to make a go of it, and things like gyms and churches and DMV offices. I got my Florida driver’s license in a half-repurposed mall. It was strange. [Continue reading…]
Boffins concoct interference-busting radios (The Register)
Radio interference can be a pain to deal with, regardless of whether it’s a rogue baby monitor interrupting your Wi-Fi or a stadium full of smartphone signals drowning each other out.
However, brainiacs at MIT say they’ve developed a radio chip that can see through the noisiest RF hellscape by actively blocking unwanted frequencies before they can scramble messages.
The chip was developed to address the growing challenges associated with 5G and other wireless communications standards. It takes inspiration from several adjacent domains – including digital signal processing and applied electronics – explained Negar Reiskarimian, assistant professor of electrical engineering and computer science at MIT.
The work, presented at the International Solid-State Circuits Conference (ISSCC) last week and detailed in a recent blog post, combines a number of existing technologies into a novel radio chip, which researchers say can contend with RF interference 40 times higher than existing wideband receivers. What’s more, they say the method doesn’t require large, bulky filtering equipment.
Even in its current development stage, the chip is small enough – just 0.65mm square – for use in mobile devices, according to Reiskarimian and Soroush Araei, an MIT grad student working on the project. And while 5G is highlighted as a potential application for radios based on the design, they note there’s no reason it can’t be used for other wireless signals like Wi-Fi. [Continue reading…]
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International Solid-State Circuits Conference (ISSCC) applies to 5G phones which is a digital signal. Digital transmission signals use COFDM and forward error correction where additional content related error correction numbers are used to mathematically correct the errors in transmission. To improve the efficiency of the resulting data is shuffled in order prior to transmission and is deshuffled in reception this spreads she errors in time which makes the correction of bursts of interference more efficient. All of these techniques is used in Wifi, 5G, DAB+, DRM, ATSC3.0 TV, DVB-T2, DVB-T and ISDB TV signals. These techniques were made possible by the radio physicists at Australia’s CSIRO who were looking for black holes. All wifi manufacturers were forced by a USA court to pay the CSIRO for breaching patent violations.
An summary since 5G operates between 0.7 – 28 GHz noise levels are much lower than at much lower frequencies. None of the above techniques can be used for AM and FM broadcasting because they are analog signals.
Correction: AM De-vitalization.
Perhaps I am misinformed about All Access being in existence to promote FM radio.
“AM de-vevitalization” ?????
All Access, seems to be a service promoting FM radio. Yes they want to see the radio competition shrink and AM to go away.
I do not understand the push to get rid of long distance radio broadcasting such as AM & SW.
I for one, value my ability to seek out other perspectives besides my local stations and in an emergency, AM is invaluable. I tune in AM radio for vital weather information not FM.
Correction: AM De-vevitalization.
Perhaps I am misinformed about All Access being in existence to promote FM radio.
This was the first digital phone. was a 2G pbone one of which was the first iphone occurred in 2007.
AM started at the same time the T model Ford hit the market. Why do you all stick with analog when the rest of the electronic world has gone digital. When is broadcast radio going to go truely digital without an analog simulcast? 3 low power all digital HD radio transmitters in the medium frequency band does not count as adoption!
Digital Radio Mondiale will operate from any channel frequency from 198 kHz to 230 MHz. Gone will be the lack of high pitched mono sound complete with distortion and noise. The long distances you crave is determined by the frequency of transmission and not on the type of modulation used. India has 3 x 1 million watt DRM transmitters. Each transmitter is carrying 2 sound programs and some data. 47 MHz and above a channel carries 3 sound and a data channel, but a single transmitter can carry 6 such signals. All of this and the electricity consumption is drastically reduced.
Data includes slideshow and large amounts of indexed text. drm.org
Anything that helps minimizing RFI on AM is, of course, always welcome but what we REALLY need is a Brother Stair filter. 🙂
Brother Stair filter can only be inserted if the receiver is a super-hetrodyne design, which converts the received signal to 455 kHz and then filtered and amplified.
New radio designs including mobile phones, infotainment systems , digital TVs and Software Designed Receivers (DSP) convert the incoming frequency to 12 kHz which makes interference supersonic which is inaudible. It is also easier to get a software filter to produce a brick wall drop off at 24 kHz.
The real problem is the radiation of noise from nearly all electrically powered devices as well as electricity line insulators and lightning. When a signal is fed into a mixer which converts the incoming signal to a lower frequency. The mixer input is the incoming signal and a local oscillator. The output is not only the difference between these frequencies, there is the sum of the two frequencies, multiples of the same along with multiples of the two input frequencies. For Digital Signal Processing, (SDR) receivers, the analog to digital converter is also susceptible to the above effects which is why the higher the number of bits the less this problem.
In short, any strong signal can modulate the wanted signal and cause audible interference. Super-hetrodyne receivers have a filter connected to the antenna to remove unwanted signals prior to conversion. SDR receivers need them to, but they add to the cost and bulk of the receiver.
The Federal Communications Commission needs to enforce https://www.ecfr.gov/current/title-47/chapter-I/subchapter-A/part-15/subpart-B on electric vehicles.
AM broadcasting, especially shortwave, is vital in rural and remote areas. FM, DAB+/HDRadio and even satellite do not cut it. Internet access is not everywhere so streaming is not a solution where distances and locality are far from metropolitan areas.
I think AM will live on despite what a lot of ideological nutjobs think.
I agree sir. Thank you. Im a huge fan of AM long hall skip starting at age 8. 1968. Opened the door for me. HF Ham Military air comms. FM E prop. ect. Great hobby. AM will never just be dead. An EMP hit from the sun or foreing country its gone DOA but untill then lets all listen to WSM 650 Nashville. Best county music ever.