Tag Archives: DSP

Radio Waves: AM Buzzkill, AM FEMA Push, AM Devitalization, and RFI-Blocking Chips

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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Checking out the Xiegu GNR1 Digital Audio Noise Filter

By Jock Elliott, KB2GOM

Call me a retro-crank, an old-schooler, but part of the joy of listening to shortwave is that the signals sound like they have come from far away. There is nothing like hearing the music, the news, the commentary “filtered through the shortwaves” . . . as Edward R. Murrow once put it.

At the same time, I am a content DXer (thanks David Goren for that phrase; it fits perfectly what I do).  Merely hearing some scratchy, barely audible signal won’t scratch the itch; I want to hear what is being broadcast clearly enough to make sense of it.

And when something particularly catches my ear, there are times when I would like to minimize the noise.

That’s where the Xiegu GNR1 Digital Audio Noise Filter comes in. According to the Radioddity website (they loaned me the unit for testing) — https://www.radioddity.com“The Xiegu GNR1 digital audio noise filter is an audio processing device integrating digital noise reduction and digital filtering. It can be widely used in the external audio processing sector of all types of wireless receiving equipment such as radio transceiver, receiver, radio, to effectively reduce the background noise, improve the signal-to-noise ratio, and improve the signal identifiable degree.”

What I found is a mixed bag. I had some difficulty getting the unit to work at first when I plugged my headphones into the headphones jack on the front panel. Once I plugged the phones into the SP #2 jack on the rear panel, I found the GNR1 will, indeed, reduce the noise on a relatively “fat” shortwave broadcast signal, rolling off the static with no digital artifacts and making the signal more pleasant for long-term listening. And you can use the high cut filter and low cut filter to tailor the sound to suit your ears, and they work quite well for that purpose.

On weaker signals, however, the GNR1 did not provide as much help in reducing noise or sometimes could not hear the signal at all.

For example, at my location east of Troy, NY, I can hear the Canadian time station CHU on 3330 nearly all the time. Today I could hear the time “pips” but down in the noise. I plugged in the BHI Compact In-Line Noise Eliminating Module (which I reviewed elsewhere), and I could hear the time station better, along the with the trickling water sound that is an artifact of the BHI noise reduction algorithm. But with the GNR1, it was as if the CHU time station had disappeared, no matter what adjustments I made to the device.

Bottom line, I can provisionally recommend the GNR1for reducing noise with no artifacts and tailoring audio on strong shortwave broadcast signals, but not for weak signals.

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Advice on cancelling locally generated noise

An SWLing Post reader recently contacted me with the following question:

“What devices work well to cancel out local RFI? I’ve been told that both the Timewave ANC-4 and a number of BHI products are all worth considering.”

Unfortunately (or fortunately, for me) I’ve no experience with outboard DSP or noise cancelling devices because I live in such an RFI-free area.

I know this reader already has a Wellbrook Loop, but he’s looking for a way to even increase noise mitigation further at his home listening post.

Post Readers: Can you help guide him?  Please comment with your experience. Is a product like the Timewave or BHI the next logical step? If not, what is?

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Phil demonstrates the BHI NEIM1031 Noise Eliminating In-Line Module


Many thanks to SWLing Post contributor, Phil Brennan, who writes:

[Recently] one of your contributors mentioned that he purchased a BHI DSP unit at a discounted price. I purchased one (a different model to the one in the previous post) some months ago before I headed away travelling.

The post reminded me that I had made a small video demonstrating the DSP unit on my FRG7. The video shows me tuning the DSP on a broadcast of Voice of the People on 3912 khz. While QRM at my place isn’t too bad, it’s still present and the DSP does aid in clearing up a signal.

Voice of the People is usually jammed by the DPRK and the DSP also assists in reducing the roar of the jammer. Of course one can go to far with DSP and the audio can suffer from that underwater sound.

Thank you, Phil! The FRG-7 is an ideal receiver for something like the BHI module since it precedes on-board DSP. The great thing about an in-line module, of course, is that it can be used with a variety of receivers.

Click here to view the BHI NEIM1031 MKII on BHI’s website.

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Very Scarce Kneisner + Doering KWZ-30 DSP Receiver Surfaces on Ebay

Hailing from Germany, the KWZ-30 communications receiver was one of the first DSP receivers available. This collectable and high performance receiver is rarely seen for sale, but one is now available for a $1890.00 Buy-It-Now price from a Russian Ebay seller. Even with the few dings visible on the radio’s case, it’s likely worth the asking price to a collector.


The extensive Fenu-Radio web site has a nice capsule review of the KWZ-30, including some excellent photos.

At the $1890.00 price of this KWZ-30, you could buy a dozen SDRPlay receivers, or roughly a couple of the highly rated Perseus SDRs. Assuming available funds, is the KWZ-30 a receiver you would add to your radio shack? If so, why… or why not?

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

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The ShouYu SY-DP-330: a retro, x-bass shortwave radio


The Professor recently sent me a link to the ShouYu SY-DP-330–stating it must be the “big brother” of the ShouYu SY-X5. Indeed it is! The DP-330 sports all of the features found in the SY-X5. It is very large in comparison, though, and runs on four D batteries. The DP-330 even comes with a remote control–most likely for the built-in MP3 player.

On a side note, the DP-330 is in the only shortwave radio advert I’ve ever seen that also features a giant mega-mechanical monster robot. Classy!

Do any readers have the DP-330? Please share your comments.

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Chorus 4: The DSP chip that supports AM, FM, DAB, DAB+, HD Radio and DRM

FrontierSiliconThe London-based digital solutions company, Frontier Silicon, has announced a new DSP radio chip that offers a wide array of available modes and is even DRM ready.

I have seen no specifications for this chip yet, and do not know if it covers the shortwave radio spectrum.

Still, this might be the perfect chip to allow radio manufactures to design an inexpensive, fully digital product in countries where digital platforms are gaining strength (anywhere from the UK to India, for example).

Many thanks to Rob De Santos for apprising me of this. I’ll post the specifications when they become available. Read the full press release below:

(Source: Frontier Silicon Press Release)

Chorus 4 a single-chip solution, integrating four previously separate chips

London, 17th December 2013

Frontier Silicon announces details of Chorus 4, its next generation digital radio chip. Chorus 4 is a single-chip solution, which integrates four previously separate chips to deliver significant cost and energy consumption savings.

Chorus 4 is the fourth generation chip from Frontier Silicon. The chip is designed to encourage the continued advance of digital radio around the world by supporting all major global digital radio standards. Chorus 4 provides solutions for multiple devices, including consumer radios, the automotive aftermarket and, for the first time, smartphones and tablets. The company’s previous solutions have already powered over 20 million digital radios worldwide.

The key features and benefits of Chorus 4 are:

  • Low cost, single chip solution: integration of RF front-end, baseband, application processor and DAC (“four chips in one”) delivers significant cost savings which enable high quality, entry-level price point digital radios
  • Ultra-low power consumption – one month’s listening for 5-6 hours a day on a portable radio with four D cell batteries (comparable to FM performance)
  • Multiple solutions for portable and table-top radios, smart-device docks, wireless speakers, hand-held receivers, sound-bars and audio systems
  • Automotive aftermarket – solutions for head units, integrated convertors and low cost adapters
  • Smart devices – enables digital radio solutions for mobile phones and tablets
  • Bluetooth connectivity – connecting smart devices and digital radios to enable hybrid radio (with interactivity and additional content delivered via IP), music streaming and remote control
  • Integrated service guides – new software will enable listeners to select stations from a single list of digital and analogue stations regardless of platform
  • Multiple radio standards – including support for AM, FM, DAB, DAB+, HD Radio and DRM

Digital Tick compliant – Chorus 4 solutions meet all technology requirements of the UK minimum specifications for both domestic and automotive digital radio devices.
Frontier Silicon CEO, Anthony Sethill, said

“Chorus 4 represents a step change for the digital radio market. After ten years of development on this and previous solutions, we now have our fourth generation chip – an integrated, single chip offering enhanced functionality, lower cost and significantly greater energy efficiency. Chorus 4 will power multiple devices, including low cost automotive adapters and devices with Bluetooth connectivity. For the first time, digital radio in mass deployment smartphones will become a viable proposition. As a multi-standard chip, Chorus 4 will address emerging opportunities around the world. I look forward to working closely with broadcasters, transmission operators and device manufacturing partners to address these exciting opportunities.”

About Frontier Silicon Limited

Frontier Silicon is the world’s leading supplier of integrated circuits and modules for digital radio and connected audio products. Frontier Silicon is part of the Toumaz Group, a pioneer in low-power wireless semiconductor and software technologies for the consumer audio and wireless healthcare markets.

The group is headquartered in London, England, with design centres in Oxford, Cambridge, Hong Kong and Romania. The company also has sales and technical support teams in Hong Kong, China and Japan.

Frontier Silicon’s audio products offer solutions for DAB/DAB+, Internet radio and connected audio – from silicon through software to production-ready platform designs.

Customers supplied by Frontier Silicon include Argon, Bang & Olufsen, Bose, Bush, Denon, Dual, Geneva, Goodmans, Grundig, Hama, harman/kardon, Hitachi, JVC, Magic Box, NAD, Onkyo, Panasonic, Philips, Pinell, Pioneer, Pure, Revo, Roberts, Ruark Audio, Sangean, Sanyo, Sharp, Sony, TEAC, TechniSat, Tivoli Audio and Yamaha.

Frontier Silicon is a trademark or registered trademark of Frontier Silicon Ltd.

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