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Getty Images/Caiaimage/Rana Dias

The FCC tentatively plans to allow AM stations in the United States to convert their transmissions to all-digital on a voluntary basis, using the MA3 mode of HD Radio. The five commissioners in November unanimously approved a Notice of Proposed Rulemaking that proposes technical standards for all-digital AMs, including adoption of the NRSC-5-D Standard, and asks for comment on the impact of all-digital operations on analog stations and listeners. 

The proceeding was prompted by a petition in March from Bryan Broadcasting Corp., as RW has reported.

MANY QUESTIONS

Below are highlights of the 33-page NPRM. At press time the final text had not been published, but details had been published before the FCC vote and were not expected to change in substance:

The NPRM opens with background about the state of AM and its various challenges; the benefits of digital transmission; and the history of in-band on-channel technology including the hybrid (MA1) service mode. 

It then described technical testing by NAB Labs (now Pilot), noting that field testing found that all-digital transmission resulted in a clearer, more robust signal, with greater daytime coverage than a hybrid signal, but that lab testing raised concerns about possible co-channel interference and the ability of all-digital signals using standard transmission equipment to stay within the HD Radio emissions mask.

The NPRM then detailed the experience of Hubbard Radio’s WWFD(AM) in Frederick, Md., which operates MA3 full-time under an experimental license. It noted that Hubbard experienced significant improvement in audio quality and signal robustness in the all-digital mode, but that its facilities first had to undergo considerable upgrades, and that the station continues to experience transmission issues that limit all-digital capabilities, such as the ability to transmit song and artist visual metadata.

The FCC then set out a list of areas it wants to hear comments about. 

Regarding the predicted benefits of all-digital AM broadcasting, it asks dozens of questions about improved audio quality, auxiliary data, improved useable signal coverage, increased programming choices (such as music) and energy and spectrum efficiency. 

It also asked for comment on potential interference, including adjacent-channel, co-channel, digital-to-digital and nighttime interference. 

[Dave Kolesar recognized for converting WWFD(AM) to full-time, all-digital transmission]

It set out proposed operating standards, including power limits, emissions mask requirements, a new carrier frequency tolerance standard, a notification requirement for stations converting to all-digital and EAS requirements, and asked for comments on all of that.

It further wants to know about the costs of conversion for AM licensees, the readiness of the public to transition to all-digital reception and the rule changes needed to implement the proposal.

SOME SPECIFICS

Specifically about the potential benefits, the FCC tentatively concluded that all-digital operation would improve the audio quality of AM broadcasts. “Compared to hybrid mode, all of the modulated transmitter power is dedicated to the digital carriers, in theory resulting in a significantly more robust reception even in the presence of a stronger analog co-channel signal.” 

But it listed some qualifications — for instance, that NAB Labs had reported some interference from bridges and power lines that caused the all-digital signal to drop out, and one instance of apparent nighttime interference to all-digital reception from first-adjacent stations operating in hybrid mode. 

So it asked for input on numerous questions around signal quality, such as whether all-digital operation would provide listenable signals at relatively low signal strength levels or at the outer listenable fringes of the all-digital signal coverage, particularly where a co-channel signal is encountered. It asked about the reception capability of digital receivers over analog, as well as the impact of power lines and other potential noise sources.

Regarding the work by NAB Labs work and the reports from WWFD, the FCC said that this research “confirms the overall value and feasibility of all-digital broadcasting” but noted that those results have not been evaluated by the National Radio Systems Committee. And it asked whether certain areas need more research, including RF mask compliance, the effects of noise on all-digital coverage area and potential co-channel and adjacent-channel interference.

[Read our ebook: Digital Radio Developments]

The NPRM then digs into other areas over 33 pages. Here’s just a sampling:

Auxiliary data — Backers say all-digital will let AMs provide services like stereo audio, song and artist ID, and emergency notifications with text and images. The FCC asked, among other things, whether it should allow flexibility regarding the use of additional channel capacity as it does with hybrid stations, and specifically whether there’s potential in the AM service for future multicast channels.

Signal coverage — Do people agree with the FCC that based on available evidence, an all-digital signal offers the potential of greater useable signal coverage than analog or hybrid? The commission also asked whether it should monitor that a station’s digital coverage corresponds to its previous analog coverage, and if not, what it should do.

Energy efficiency — Will all-digital operation offer greater energy efficiency and utility cost savings for AM broadcasters? 

Spectrum efficiency — Will all-digital operation help realize the full potential of digital technology for spectrum efficiency? What are the implications of using current 20 kHz AM channel assignments in all-digital mode?

Interference — The NPRM’s many questions around interference include whether the existing framework for interference protection is sufficient, or whether there are concerns unique to all-digital that should be accounted for in rules governing groundwave and skywave protection of AM stations. 

Will all-digital cause interference to co- and adjacent-channel analog stations? Shouldn’t all-digital present fewer interference concerns than hybrid mode? 

Is the FCC right in thinking that co-channel interference is more of a concern than adjacent-channel? What does the industry think of existing research about the potential impact of all-digital signals on co-channel analog stations, in and outside their protected contours?

[Letter: Digital Radio vs. 5G]

The FCC noted that when it first authorized nighttime operation for AM stations, it had stated that “the benefits of full-time IBOC operation by AM stations outweigh the slightly increased risk of interference …” The FCC asked whether that earlier reasoning applies to the potential for co-channel interference as a result of all-digital operation.

How might the likelihood of co-channel interference from all-digital stations be minimized; and how should the FCC resolve impermissible interference if it occurs?

What about digital-to-digital interference? Is it true that if all AM stations were digital, co-channel interference would be less, thus potentially increasing groundwave coverage for a given power level and carrier frequency? If the all-digital mode increases the power and bandwidth occupancy of the digital carriers, how might this affect adjacent-channel digital transmissions? What would be the impact of all-digital stations on hybrid ones? 

Nighttime operations — Should the FCC allow AM all-digital at night, given that propagation characteristics vary markedly between daytime and nighttime? How would all-digital affect potential interference caused by skywave propagation? What additional study and testing might be needed?

Receivers and consumers — Are consumers ready? Is 55 million HD Radio-equipped cars a sufficient number? Are non-car receivers readily available and affordable? How many HD Radio receivers sold in the past are still in operation? 

[Symposium Examines Changing Radio Landscape]

The FCC also wants to know about the impact of all-digital on listeners with analog-only receivers. “What is the estimated size of this audience, and their estimated frequency of use of such receivers? In a market with very few stations, a single station’s conversion to all-digital could reduce options for analog-only listeners.” Should the FCC require a station converting to all-digital to show that it is not the only full-service aural service within its community of license county? Would preserving the long-term economic viability of an AM station and the public benefit of improved service to some listeners justify the present-day loss of service to other listeners? Should the FCC require a converting station to notify its listeners, and in what way?

The NPRM also includes discussion about operating rules; emissions mask compliance (with the FCC noting that “the NRSC has not evaluated it and NAB Labs testing indicated that all-digital stations might have difficulty complying with it”); how signal power should be measured; what carrier frequency tolerance standard to adopt; the impact on EAS and TIS/HAR operations; the likely costs to station of converting; and other factors that might encourage more widespread adoption of all-digital broadcasting within the AM service.

The final NPRM text had not been published at press time, and comment deadlines were not yet set. The first deadline would be in or after late January. Search for “All-Digital AM Broadcasting Revitalization of the AM Radio Service” in MB Dockets No. 19-311 and 13-249.

The post FCC Takes Your Questions on AM All-Digital appeared first on Radio World.

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Dismissed the Petition for Reconsideration

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We’ve written about electrolytic capacitors lately. I found a funny video of what happens when you mistakenly connect the “+” voltage to the negative terminal of an electrolytic in a simple flasher circuit. Take a look online at https://tinyurl.com/rw-work-cap (and don’t try it at home).

No identities of where this submission originated. After all, we’ve all probably experienced this or seen it happen to someone not respecting that “+” symbol.

****

While we’re on the subject of capacitor education, have you heard of ultra-capacitors? A brief tutorial explains the ultra-capacitor and its ability to store tremendous amounts of energy. Watch it at https://tinyurl.com/rw-work-cap2.

Also discussed is ESR, Equivalent Series Resistance, which we’ve covered in this column. ESR is a small internal resistance that limits current. In the case of the ultra-capacitor, the ESR is an amazingly low 7 milli-ohms! This means the ultra-capacitor can discharge hundreds of amps.

Capacitors of this size are used to dump hundreds of amps quickly; one application is handling the sudden stops and starts in electric cars. In the experiments in the video, you can see them used to vaporize bits of metal and circuit board traces. These are powerful components, not to be played with, as you will see. In addition to explaining some capacitor theory, the video demonstrates how dangerous innocuous components like capacitors can be. 

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Paul Sagi writes from Malaysia that the company SDRplay has released a software update that allows you to scan a wide swath of bandwidth using a software-defined radio. For those new to this technology, SDRs replace traditional components like mixers, filters and amplifiers inside a receiver using software on a personal computer to replicate those component effects.  

This new software permits rapidly scanning in 10 MHz (or less) chunks over the SDRplay’s frequency range. It’s a software-defined spectrum analyzer! See www.rtl-sdr.com/tag/spectrum-analyzer-2 for more info.

Paul writes that years ago he had equipment on the bench and physically adjusted tuned circuits. Now that function is all handled in software, which makes sense; tuning a filter simply changes the mathematical function of the filter, and computers now have the capability to perform the math quickly enough.

**** Fig. 1: Home Depot has a clamp assortment every engineer can use.

My Telos colleague (and SBE board member) Kirk Harnack found a virtual bonanza for engineers at Home Depot! It’s a 22-piece reinforced spring clamp set, made out of fiberglass nylon. The best part? The set costs less than $10 for 22 clamps! These aren’t cheap clamps, either. They have non-slip grip handles and vinyl tips to protect the work they are gripping. 

At homedepot.com, enter 302755768 in the search field to find this.

Readers who have seen my Workbench presentations for the SBE may remember using the spring clip on a clipboard to hold components while soldering. With the variety of sizes in this set, there’s a clamp for any size job.

[Scarlet Knights’ Station Gets a Fresh Start] ****

You know how important it is to conserve your resources, even if it’s cool air. Kevin Wagner is the operations director for Eagle Communications in St. Joseph, Mo. Not long ago, Kevin invested in a new, smaller transmitter, and the upgrade left him with a large empty room.

Fig. 2: Plastic flaps contain the cool air at a transmitter site.

The snag was that he was now cooling all that empty space. He needed an inexpensive means to reduce the size of the conditioned area. Sure, he could have built a wall, but what if a future tower lessee required the empty space to be cooled again? Fig. 2 show’s Kevin’s solution.  

You see these plastic flaps used in refrigerated storage areas in supermarkets; they keep the cool air contained, but the overlapping flaps can be parted to permit entry into the cooled area. Plus, the fact that the plastic flaps are clear, you can see if someone enters the building while you are working.  

These freezer curtain strip sets run between $80 and $200, depending on your size requirements. Search “freezer curtain strips” on Amazon or Google.  

****

Readers enjoyed the EAS loop antenna project we told you about from Ken Beckwith, EMF field engineer. Several readers have inquired about the physics behind the wiring method used; Ken has been gracious enough to explain. 

The question dealt with grounding the shield of the conductors. In Ken’s design, the shield on the wiring is the primary of a transformer that actually receives the AM signal. The wire conductors form the secondary of the transformer, and provide the signal to the RF connector going to the receiver. If the shield was not grounded, there would be no voltage generated in the loop. 

Not everyone knows all the tricks and tips you’ve used for years. Share your ideas in the pages of Workbench — help other engineers while you qualify for SBE recertification credit. Send tips and high-resolution photos to johnpbisset@gmail.com.

John Bisset has spent 50 years in the broadcasting industry and is still learning. He handles western U.S. radio sales for the Telos Alliance. He holds CPBE certification with the Society of Broadcast Engineers and is a past recipient of the SBE’s Educator of the Year Award.

The post They Don’t Call Capacitors “Old Sparky” for Nuthin’ appeared first on Radio World.

The author is project directory for WorldDAB.

Bernie O’Neill

Today, there are more than 25 DAB+ audio services available to listeners in Poland, eight of which are exclusively available on DAB+ digital radio. That said, much of the radio landscape in the country has remained unchanged, and despite a number of stations launching on DAB+ in recent years, the geographical share of DAB+ in the country is the same as it was when it first launched just under five years ago.

However, as confirmed by KRRiT [the National Broadcasting Council of Poland] at the WorldDAB General Assembly 2019 at the start of November, all this is about to change as Poland prepares to resume the development of its DAB+ network over the next few years.

Poland’s (national and regional) public broadcasters are currently operating the only multiplex in the country, but as revealed at WorldDAB’s flagship event in Brussels earlier this month, a new, three-step expansion plan is set to start in October 2020 and conclude in October 2022.

As part of this plan, which for the most part will focus on highways and other main roads, population coverage is set to reach 68.2% by the end of the first, 77% by October 2021 and over 81% by the end of the third phase, in October 2022.

Speaking at the General Assembly, KRRiT strategy expert Krystyna Kuhn touched on KRRiT’s five-year regulatory strategy for the period leading up to 2022, pointing to the growth of DAB+ and the launch of two new multiplexes as one of the key priorities for the National Broadcasting Council of Poland.

DAB+ digital radio first launched in Poland in 2013, with two transmitters going into operation in Warsaw and Katowice — two the most populated agglomerations in Poland — and covering over 17% of population.

In October 2015, Poland’s DAB+ network included 24 transmitters in 17 locations across the country, covering over half (55.5%) of Poland’s population and a third of its territory, and it now seems the Polish radio industry is ready to take another step forward towards digitisation.

November also saw the first licences for regular transmissions on local multiplexes being granted for the cities of Warsaw, Katowice, Poznań, Rzeszów, Częstochowa, Toruń and Tarnów.

And despite an apparent lack of DAB+ marketing campaigns, the new international DAB+ logo is increasingly being used by key stakeholders in Poland, while the number of receiver sold in the country continues to grow — there are now over 100.000 DAB+ receivers in the market, excluding devices sold over the internet.

The post DAB+ Development Resumes in Poland appeared first on Radio World.

Digigram says its IQOYA *VIP software brings flexibility to the way users manage, connect and deliver content for radio.

A scalable solution, IQOYA *VIP provides comprehensive audio routing along with IP audio streaming, encoding and decoding. It helps telcos and content delivery networks (CDNs) to design full end-to-end IP audio transcoding and routing functions, it opens doors to “radio-as-a-service” solutions.

In addition, says the company, by offering easy integration of IP streams, it adds value to automation system providers and radio stations.

IQOYA *VIP is hosted on a server in the cloud and brings studio facilities to one’s fingertips. It features simultaneous encoding/decoding, with transcoding capabilities, encoding of multiple audio streams, multiformat IP live streaming (including RTP/UDP, MPEG-TS, and Icecast/SHOUTcast) and stereo audio or multichannel I/O.

IQOYA *VIP runs under Windows or Linux. The service can be operated through a web GUI or a web service API. Once setup, it’s autonomous, hidden inside the system. When used as part of an automation system, IQOYA *VIP works just like any standard audio device.

For information, contact Digigram in France at +33-4-76-52-47-47 or visit www.digigram.com.

The post Digigram IQOYA *VIP Eases IP Radio appeared first on Radio World.

Dave Kolesar
Photo by Jim Peck

The recipient of the Radio World Excellence in Engineering Award for 2019-2020 is Dave Kolesar, CBT, CBNT, senior broadcast engineer at Hubbard Radio. He is recognized for his initiative in converting AM station WWFD in Frederick, Md., to full-time, all-digital transmission, the first AM station of its kind in the United States, and for advancing our industry’s discussion and awareness of the potential uses of the HD Radio MA3 mode. 

The FCC in November proposed to allow all U.S. AM band stations to convert to all-digital if they wish, and is taking comments on the idea now. While many people have played a role in advancing voluntary conversion, Kolesar is recognized for advocating within Hubbard for the experiment, which necessitates turning off a station’s analog AM signal entirely, and then executing it over several years. The experiences and findings at WWFD are an explicit part of the FCC’s NPRM text, and its project continues to produce insights that are likely to be of benefit to other broadcasters.

Kolesar is transmitter engineer for WTOP(FM), Federal News Radio as heard on WFED(AM), and WWFD. He also is program director of The Gamut, the format broadcast on WWFD. Prior to Hubbard, he worked as an electronics engineer in the Information Technology Division of the U.S. Naval Research Laboratory. He holds Master of Electrical Engineering and Bachelor of Science in Physics degrees, both from Catholic University.

We talked with him in late November.

Radio World: What brought you into radio engineering?

Kolesar: It goes all the way back to when I was five or six years old, when my parents bought me one of those Radio Shack AM broadcast station kits. I put it together and it was magic. 

I borrowed my older sister’s record player and her stack of 45s, and I would torture my parents playing DJ and making them listen to me on the radio. 

Growing up in the D.C. area and listening to some of the big radio personalities in the 1980s, I was inspired by all of this. I ended up teaching myself electronics to build bigger studios and bigger transmitters. By the time I was 13, I put on the air this little radio station out of my bedroom. We’ll call it Part 15 and a half. 

The basement studio of what Kolesar, right, calls his “Part 15 and a half” station in 1999, operating by then online. He is with co-host Brennan Kuhns. “Most of the people who passed through the station were musicians, performing live on the weekly Friday night show and causing the show to become a focal point in the local music scene in Prince George’s County, Md. The Gamut on WTOP HD3 and WWFD is a direct descendant of this station.”

I started a campus radio station in high school. I was the engineer of our college radio station. I went to Catholic University in northeast D.C. I kept my station. In college, I took my little hobby venture online and I kept running that even throughout my career.

I tried to get a real job. I worked for the Naval Research Lab for five years as an electronics engineer after grad school, and I still kept my hobby going online. When a job opening at WTOP appeared, I decided to finally give a shot of unifying my hobby and my career. I started working part-time at WTOP; in 2006 I started working full-time. 

Then my career life took another random direction in 2011 when WTOP was sold from Bonneville to Hubbard. The HD3 station on WTOP, which had been, by corporate edict, airing the Mormon Channel, went silent. Joel Oxley, the GM of WTOP, suggested that we put my own internet radio station on the HD3, and that’s how The Gamut was born. 

Eventually it got put on 820 [kHz], so having control of that station, it became easy for me to suggest digital on it.

Installation of a new phasor for WFED in 2008. RW: There must have been a day when you said to somebody, “Hey, I’ve got this idea. Let’s turn off the analog and try out all-digital.” Most AM owners aren’t going to jump at that.

Kolesar: What made the conversation easier was the fact that we had gotten an FM translator for the station. I think it was about Christmas-time 2016. I knew the translator was coming. At a lot of other stations, as soon as they get the translator, especially a music station, listenership migrates immediately to the FM translator, making the AM station little more than a legal justification to put this low-power FM signal on the air.

Knowing that this was in the future of that signal, I thought, “Well, what can we do to make this more than just a legal justification? What can we do to actually have the station add value in the quest for listeners? How can you make this valuable?” 

Onsite in 2008.

Around 2008 or 2009, I’d heard the MA3 tests that iBiquity was running on 1670 on its experimental station, which was diplexed with WWFD. I was already privy to firsthand knowledge of how MA3 could sound and how robust it was and how well it covered. 

The thought occurred to me, well, why don’t we just try that; that way we could use our FM signal and tell people that, “Hey, you know, we’ve got this AM station. When you start to lose reception, flip back to 820 and listen to the station for another 30 or 40 miles while you’re driving.”

And I’ve told people before how I went to the CES in 2017 and approached the Xperi booth.

In order to sell it to management, the process was not as difficult as I’d anticipated, because the FM translator seriously reduced the risk of a digital conversion. Also WWFD is not one of the main signals in the Hubbard D.C. market. It’s up in Frederick; I guess you could say it was never going to be a big moneymaker anyways. It was easier for Hubbard to say, “Let’s take the risk on this smaller asset and see if you can make something of it.” I wasn’t going to convince Hubbard to do it on a 50 kilowatt AM signal first.

I should stress that I’ve been working extensively with Mike Raide at Xperi Corp., who having worked with MA3 himself, didn’t need convincing that this was a great idea. All of these digital AM efforts wouldn’t have happened without him. 

RW: Somebody who runs an AM station will want to know how good it can sound.

Kolesar: An honest assessment, it can sound as good as the best FM HD2 signal that you’ve ever heard. The bitrate for the digital signal is about 40 kilobits, and so that’s about equivalent to probably one of the higher-quality HD2 signals. And with proper audio processing, you can make that sound just as good as an analog FM. 

It’s got frequency response out to 15 kHz; it’s stereo; you have title, artist and album metadata, as well as images such as station logo and album artwork. So not only do you have aural parity with everything else that you might find in a car dashboard, you have visual parity as well.

RW: The FCC has opened an NPRM now. 

Kolesar: I think that it was very wise of the FCC to act quickly on the NPRM. The analog AM audience is not getting any bigger. AM is in a bit of a race against time to reinvent itself before, quite frankly, at least in many areas of the country, it’s forgotten. AM is battling for relevance right now.

Everybody will say content is the problem or content is key, and that’s absolutely true; but the medium itself limits what kind of content can go on it. As a result, AM is at a competitive disadvantage, it’s only conducive to certain types of programming. 

All-digital AM erases that disadvantage; any kind of programming that you could put on FM or even a streaming broadcast or a satellite broadcast can be put on an AM station with digital. 

RW: Do you see a day when this dramatically revitalizes the band, because suddenly AM stations sound a lot better, and big-market stations would start to consider doing it? The answer clearly involves receiver availability, but is there a big-picture upside, or is this more sort of a holding strategy?

Kolesar: Let me tell you where I think receiver design is going. Most terrestrial broadcasts are listened to in vehicle, so we need to talk about what the car radio of the future is going to look like. 

For Kolesar, a key selling point of digital is that “it puts AM in the ecosystem of digital audio delivery into the dashboard.” Here, WWFD “The Gamut” is displayed on the HD Radio receiver of a 2019 Toyota Highlander.

Receiver design is trending towards tuning by visual metadata. You’re going to see receivers that scan the bands and will display the content available in the area as thumbnail icons on a screen. You see the programming that’s available to you, then you’ll see a bunch of station logos. You press the button and you hear programming that is available in your area. Now that programming could be on AM, FM, it could be a satellite program, it could be a stream that you have bookmarked. It won’t necessarily be obvious; it’s just content; but it has to be digital content in order for the receiver to display that metadata. 

The way that you’re listening to an audio program in the car won’t necessarily be inherently obvious; it’s just that digital AM is going to be one solution “under the hood,” to get local content to receivers. It puts AM in the ecosystem of digital audio delivery into the dashboard. People aren’t necessarily going to say, “I listen to AM radio,” it’s just yet another way of delivering content. 

Kolesar did some work at the High Frequency Active Auroral Research Program (HAARP) site in Gakona, Alaska. Early warning radar that shuts down the transmitters when a nearby plane is detected is to the right, with the array in the background.

Since we’ve got all of this broadcast infrastructure in the United States already built for medium-wave transmission, this is a great way to bring it up to date and to keep it relevant in the car. That is what I see as the end game. It will probably go that way with or without AM; this is just a way of making sure that AM is part of that solution.

I imagine there’s going to be a number of stations who see a competitive advantage to going digital early on, stations frankly with not as much to lose; and they will build, like WWFD is building, a new audience from scratch. Then as people start listening to those services, the bigger stations will take note. Probably the last stations to convert will be the established legacy stations with significant analog audiences. 

Right now about 25% of cars on the road are capable of receiving HD Radio. As the program director of a triple A station on AM, I would rather take my chances with that 25% than with the 100% who could get it but would refuse to because of quality. 

RW: What question do you hear the most from industry colleagues?

Kolesar: The biggest concern is receiver penetration right now, because an AM station with a substantial analog audience is going to take a look at the 25% number in the car and say that’s not good enough to switch. If they have an established audience, they may want to wait a few years. 

Over half the cars being sold now have HD built into them, and that number is going to continue to go up, so both through attrition and new sales, the percentage of cars with HD Radios are going to increase. For an established analog player, it becomes a waiting game of at what point would you switch over and perhaps even gain a new audience from people who are willing to hear your programming in higher quality.

Receiver penetration numbers are good enough for new players; established players would probably want to wait a little bit.

RW: What would a typical station expect to spend to update their facilities?

Kolesar: There’s two pieces to look at. There’s your antenna system and there are the transmitters. If you’ve maintained your antenna system and you have a new transmitter or one that’s capable of all-digital operation, your costs of going digital could be very minimal. If you have to do a complete site rehabilitation, you might be spending tens of thousands of dollars, and you might be talking about buying a new transmitter. If you’re a 50 kilowatt AM, that’s well over $100,000. 

I ask people, “Have you done the hybrid mode of HD in the past? If you have, then your antenna system is already compliant for MA3 operation, so you likely will not have to do anything with your antenna system.” Then I ask what kind of transmitter they have. If you’ve got an old tube rig, you’re going to have to buy a new transmitter. If you have something like a Harris DX series, a Nautel NX series or even an XR series, chances are your transmitter is ready or could be easily modified. It really depends on what kind of shape your antenna system is in and what kind of transmitter you have.

RW: If the FCC acts quickly and makes it optionally available to everybody, how many stations would switch?

Kolesar: I truly do not know. You’ll probably see a number of smaller stations, maybe Class B and C stations with translators, switch relatively quickly. 

A number of stations have approached Xperi and me about converting; the stickler is the fact that an experimental is required. Informally we could probably say that the FCC, looking to further the art of AM broadcasting, would be inclined to renew an experimental for MA3 operation; but a station owner may not want to make an investment in something that could be taken away in a year. 

RW: Is it going to add a lot of interference on the band and make noise even worse?

Kolesar: I don’t believe so. Remember, these digital stations are living in the analog allocations world. They still have to meet the same emissions mask, they still have to meet the same power levels, they still have to abide by the same protection scheme. 

Dave Kolesar and his husband Patrick Wojahn visit the WSM transmitter site on a 2013 visit to Tennessee. Note base insulator in rear. Challenging convention is not something new for Kolesar; in 2006 he was among several people represented by the ACLU and Equality Maryland in a marriage equality case considered a landmark in efforts to assure same-sex couples the right to marry.

I can just relay my qualitative experiences with WWFD. For instance, in our nighttime interference-free (NIF) contour, when we were analog, you couldn’t listen to adjacent-channel stations, 810 and 830, because of modulation splatter. When we went digital, all of a sudden you can hear 810 and 830 — not perfectly, because you hear the digital hiss underneath these stations, but the digital-to-analog interference, at least to my ear, is more palatable because it just comes across as background static rather than a splatter that would ruin intelligibility. My personal experience has been that digital-to-analog interference is not as severe as analog-to-analog interference. 

RW: Closing thoughts? 

Kolesar: I think MA1, the hybrid mode of HD Radio, did a disservice to MA3, because MA1 doesn’t work well. At best MA1 is a compromise. It compromises the analog and it certainly compromises the digital. So people have based their perceptions and have hardened their opinions about digital AM based on their experiences with the hybrid mode. In that sense hybrid has done a disservice to the potential of a digital transition for AM. 

The MA3 mode of HD Radio is much more robust because all the power goes into the digital carriers rather than the digital carriers being 30 dB down from the analog signal, as it is in the hybrid.

You have better sound quality. Even though the bitrates are somewhat comparable, the sound quality in MA3 in general is so much better because you can process it specifically for a low-bit rate digital stream; in the hybrid mode you have to process the digital signal similar to how you would process an analog AM signal, so that it would be an easy transition on the ear between analog and digital, and as a result the digital didn’t sound nearly as good because a lot of stations processed their digital portion of the hybrid signal too aggressively. The codec didn’t have that many bits to work with, and it ended up sounding muddy, whereas in this case you really can approach FM-like sound quality with the all-digital mode. 

In summary, the hybrid mode did a disservice to the all-digital mode. And now there’s a bit of re-education that has to go on in terms of selling people on the notion of digital AM.

Comment on this or any story to radioworld@futurenet.com.

Past recipients of the Radio World Excellence in Engineering Award are Andy Andresen, Mike Starling, John Lyons, Clay Freinwald, Jeff Littlejohn, Gary Kline, Milford Smith, Barry Thomas, Paul Brenner, Marty Garrison, Wayne Pecena, David Layer, Mike Cooney, Larry Wilkins and Russ Mundschenk.

The post Kolesar Sees the Promise in All-Digital on AM appeared first on Radio World.

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Media Bureau issues Order resolving complaints and admonishing licensees for violation of section 315(e)(2) of the Communications Act of 1934, as amended (Act)

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