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While it hardly qualifies as cutting-edge technology, the project described here did provide a solution to an annoying problem I have faced several times: How do you get a decent off-air signal from an AM station, where the studio is in a modern curtain-wall office building and is located at or beyond the 5 mV/m contour of the station?

I saw evidence that several engineers had explored solutions in the past. The hardware was still around when I arrived. A very nice (and pricey!) commercially-made shielded loop was installed on the roof with inside phantom power for its preamp in the studio racks seven floors down. That didn’t really work. A better antenna signal could be had from the coax shield than from the actual loop antenna and preamp output.

Another iteration was the installation of pre-amplified loopstick antennas, taped to the window glass in one of the studios with coax routed back to the rack-mounted receivers. This, too, yielded a marginal signal — enough to tell if we were on the air, but not useful for critical evaluation at all.

Yet the stations both had very usable, listenable signals on my car radio parked in the building driveway.

A COMMON PROBLEM

As is always the problem with metal-skinned buildings, the openings in the exterior walls behave like sections of waveguide at frequencies below cutoff — virtually all of the field is cancelled. I concluded that no inside solution would ever work satisfactorily. Long runs of coax also weren’t working.

How could the car radio result be replicated in the building? To do that, I borrowed old technology and married it with some moderately-priced new technology to build what I believe is a solid solution.

Fig. 1: Home-brew shielded loop antennas.

I fabricated two shielded loop antennas from home center components as shown in Fig. 1. Inside the tubing is 10 turns of ordinary hookup wire. I used some multi-conductor wire and joined the ends to make one long wire length (see Fig. 2). Recall that the purpose of a shielded loop is to make the antenna responsive to only the magnetic component of the transmitted signal.

Fig. 2: Multi-conductor wire with the ends connected together was used to make the actual loop conductors. Note the variable capacitor used to resonate the loop.

The shield is there to prevent successful capacitive coupling with electrostatic fields. Since the electrostatic fields from AM stations (and from most sources of interference) are vertically polarized, the electrostatic field induces voltage in only the vertical pieces of conduit. That same electric field exists inside the tubing as well and induces a voltage on the wire turns inside.

So how does this shielding help? Because the electric field in the vertical tubing sections induces voltage in the wire turns in opposite directions on either side of the loop. Thus the electrostatic contribution (in a perfect world) cancels. The gap in the conduit at the top of the loop (Fig. 3) is to avoid having the shield look like a shorted transformer turn, thus cancelling the magnetic component as well.

Fig. 3: A gap in the top of the loop creates the necessary electrostatic break, just like on your FIM.

This is how your field intensity meter works. Regardless that the meter scale is calibrated in volts per meter, it is a magnetic device. The relationship between the electric field and the associated magnetic field is a known constant (120π)t  and the Potomac folks figure you won’t be using the meter in other than an air environment, a pretty safe bet. Loop orientation works just like your field meter as well, with distinct nulls and maxima as you rotate it.

To provide just a bit of pre-selection to the loop, I added a small transistor-radio-style variable capacitor bought from an eBay seller. I calculated my ten turns to have about 200 microhenries, but with the capacitance contributed by the tubing and other unquantifiables, who knows?

My variable cap has two sections, each about 220 picofarads. I paralleled the sections and wired loop and capacitor as a tank circuit — the miracle of adjustable components. Just turn the dial until it works! Tune for maximum smoke. The result is a broad resonance, but helpful for me, since my location is in the 50+ mV/m field of two other AM stations.

To couple each loop to a receiver, I used some randomly chosen ferrites found in a drawer and made a small ferrite loaded transformer for each loop antenna. I figured the impedance of the loop would be low. I guessed maybe an ohm or two. So, a 1:5 turns ratio would get me somewhere in the 50-ohm neighborhood.

NON-CRITICAL DESIGN

As you’ve probably guessed by now, nothing in this design is particularly critical. The radios are ordinary Panasonic in-dash models bought on eBay for about $20 each. This, too, is anything but critical.

Now, with two steerable antennas, I have a decent signal from both stations. But how to get that RF down seven floors to the studio? The answer is not to try. Instead, I installed my two car radio receivers in a weatherproof box (see below) and clamped the whole business to a railing on the roof.

The signals from two AM stations, as well as power, are carried on a piece of Cat-6 cable following the telephone riser path down the seven floors and into our leased space. Power comes up on two paralleled pairs, and baseband audio is coupled from the radio speaker outputs on the other two pairs.

The radios I used are bridge amplifier designs, meaning that the speakers are driven in a balanced, differential way, but I used small audio transformers for isolation anyway. Preserving balance yields undiminished audio quality downstairs. I also added a local headphone jack for each, allowing confirmation of proper operation before leaving the roof.

The whole business was installed into what Amazon calls a “black, tactical, weatherproof case” as shown in Fig. 4. We’ve all seen these used for sensitive electronics that must be shipped. They have snap locks and gasketed lids. I just ordered a generously sized one and installed the shelves you see. The loop antennas attach using ordinary 3/4-inch plumbing components with the antenna coax fished through. I added reinforcement where the pipe flanges attach. Finally, the whole assembly is U-bolted to the railing.

Fig. 4: The Panasonic receivers were mounted in a black, tactical, weatherproof case.

WHAT ABOUT POWER?

Powering the system remotely involved a little I-squared-R thinking. The Cat-6 run overall was about 250 feet. Paralleled Cat-6 conductors at that distance worked out to be about 5 ohms overall. I had no idea what current the radios drew and, barely visible in the pictures, is a small lead-acid battery also in the enclosure. It’s there to hold up the radios’ channel memory if the downstairs power needs to be disconnected for some reason. It needs to remain charged.

Finally, there’s a small 12-volt fan in the box as well. I guessed 2 amps for the radios which, with 5 ohms on the way, means my 12 volts will be 2 volts on the roof. I could have done some bench measurements and built a supply, but when I can buy a 30-volt 3-amp adjustable supply with metering and overcurrent protection on Amazon for $60, why bother? The supply is pictured in Fig. 5.

Fig. 5: This $60 variable supply was perfect for powering the receivers and keeping the battery trickle-charged.

With the battery disconnected, the supply voltage was gradually raised until the receivers saw about 13 volts. I then noted the current. When the battery was connected, the voltage came down to about 12.8 and the current increased by about 50 milliamperes. That seemed a reasonable amount for trickle charging one of the 7 amp-hour batteries commonly used in UPS devices. We’ll see.

Anyway, the completed project, which is shown in Fig. 6, was simple, straightforward, not too terribly expensive, and solved a long-standing and annoying problem. For engineers it doesn’t get any better than that.

Fig. 6: The completed rooftop installation.

Frank McCoy is chief engineer of Salem Communications’ Chicago cluster. Got an idea for a hands-on engineering article? Email rweetech@gmail.com.

The post Receivers in a Box on the Roof appeared first on Radio World.

Inovonics has released firmware updates for five of its INOmini receiver-monitor models. The company says the update “improves the internal reference clock” as well as addresses other issues since the June release of these products.

The new firmware is available at each product’s description page and is also aggregated on the Downloads section. The models with available updates are:

• INOmini 661 DAB+ Firmware
• INOmini 673 FM/RDS Receiver
• INOmini 674 AM Reciver
• INOmini 676 NOAA Receiver
• INOmini 679 HD Receiver

Read instructions for downloading and installing the updates here.

 

The post Inovonics Updates INOmini Firmware appeared first on Radio World.

All four commissioners and the chairman of the Federal Communications Commission stand behind the decision to propose hefty fines against two Boston-area individuals accused of allegedly operating radio stations without a license.

At its December meeting, the FCC proposed two forfeitures — one of $151,005 and the second of more than $450,000 — an action that marks the largest fine ever proposed by the FCC against a pirate radio operation.

[Read: Failing to Notify FCC of Primary Station Change Proves Costly]

The commission proposed a forfeiture of $453,015 against Gerlens Cesar, the operator of Radio TeleBoston, for allegedly broadcasting three unauthorized transmitters on two different frequencies. According to the FCC, Cesar allegedly simulcast Radio TeleBoston on three unauthorized transmitters on two different frequencies, which had the potential to cause interference in various locations in and around Boston and at different channels on the FM dial. As a result, the commission proposed the maximum penalty amount for all three transmitters.

Cesar had been notified that his broadcasts were illegal, but the FCC said he continued to broadcast Radio TeleBoston from multiple transmitters and frequencies.

In a second action, the commission proposed a fine of $151,005 against Acerome Jean Charles who the FCC accused of being the long-time operator of an unlicensed radio station in Boston called Radio Concorde. Despite several FCC warnings, Jean Charles apparently continued to broadcast radio signals without authority at power levels that require an FCC license.

In the case of Radio Concorde, the FCC received a complaint from a local Boston-area broadcaster who said that Radio Concorde’s broadcast on 106.3. MHz from the Mattapan neighborhood in Boston was interfering with the station’s new FM transmitter station at 106.1 MHz. The complaint was investigated by field agents from the FCC’s Enforcement Bureau who repeatedly warned Jean Charles that his alleged broadcast were in violation of FCC rules.

According to the FCC, Jean Charles ignored repeated warning from FCC field agents. He has been given an opportunity to respond to the commission’s Notice of Apparent Liability before further action is taken.

According to FCC Chairman Ajit Pai, the two Notices of Apparent Liability send a strong signal that the FCC will not tolerate unlicensed radio broadcasting. In each case, he said, the pirate radio operator in question was given multiple warnings that he was violating the law. In each case, therefore, the commission moved to proposing the maximum forfeiture amount permitted under the Communications Act.

“The harms of unlicensed radio broadcasting are serious: pirate stations interfere with licensed stations — whose owners have invested time and money in providing lawful service to the public — and can also cause interference to critical public safety systems,” he said.

Pai pointed out the other “legal alternatives” to unlicensed broadcasting including former windows for low-power FM construction permits, permits for vacant FM allotments as well as internet streaming.

Both Chairman Pai and Commissioner Michael O’Rielly praised the efforts of the Enforcement Bureau, saying that field staff members “relentlessly pursue these rogue, illegal actors” even as the plague of pirate radio operations continues to persist for the FCC.

“[P]irates not only harm legitimate broadcasters and their listeners in multiple ways, but also put their own audiences at risk by failing to broadcast any emergency alerts or abide by consumer protection regulations,” O’Rielly said.

Although O’Rielly admitted that the FCC may never see a single dollar from these illegal operators, “our goal must be to use our enforcement authority to help shut down the perpetrators, those aiding and abetting, and any landlord willing to house such activities.”

 

The post FCC Proposes Record-breaking Forfeitures to Pirate Radio Operators appeared first on Radio World.

According to the latest WorldDAB market report, more than 82 million consumer and automotive DAB/DAB+ receivers had been sold in Europe and Asia Pacific by the end of Q2 2019. This, it shows, is up from 71 million one year earlier.

The new data gives an overview of DAB receiver sales, road and population coverage, household penetration and the number of national stations on DAB/DAB+ compared to FM. The report covers Australia, Belgium, Denmark, France, Germany, Italy, the Netherlands, Norway, Switzerland and the United Kingdom. It also also details the rollout status in 24 emerging markets including information on trials and population coverage.

Key findings from the WorldDAB report include:

• More than 40 million receivers have been sold in the U.K., with 65% of households having at least one DAB receiver
• In Switzerland, 65% of all radio listening is via digital platforms, and 35% of all listening is on DAB+. Switzerland has also confirmed digital switchover will take place no later than the end of 2024
• Italy, France, Netherlands and Belgium all show positive signs of growth in the last year
• In Norway, following its digital switchover in 2017, radio listening is now back to similar levels as achieved in 2016

“2019 has been an exceptional year for DAB+ radio. By mandating digital terrestrial capabilities in all new car radios, the European Electronic Communications Code is transforming the European radio landscape. This year we have seen DAB+ launches in Austria and Sweden, and next year France will launch national DAB+. In the Asia Pacific region, Australia is seeing its highest ever levels of DAB+ in new cars, and Tunisia is the first country in Africa to launch regular DAB+ services,” said Patrick Hannon, WorldDAB president. “A record 12 million DAB receivers were sold worldwide in the last 12 months, and we expect this figure to grow in 2020 as DAB+ uptake continues to rise.”

To download the latest infographic, click here.

The post WorldDAB Reports DAB Receiver Sales at 82 Million appeared first on Radio World.

We reported in May that URCA, The Utilities Regulation & Competition Authority in the Bahamas, had shuttered Sportsradio 103(FM), owned by Navette Broadcasting.

At the time, the broadcaster claimed that the decision was “unlawful and unconstitutional,” and that it was “eager” to have a date in appeals court to defend itself and prove its “rightful claim” to the 103.5 FM radio license. There is a question now, however, about whether that day will ever arrive.

In recent developments, Kahlil Parker, Navette Broadcasting’s attorney, said to the appellate court that the decision to close its client’s broadcast company was a “unilateral decision” and “without due process of law.”

The company had originally filed two appeals but then requested to begin judicial review proceedings. Navette ended up withdrawing the first two appeals, but then the court dismissed Navette’s application for the judicial review proceedings.

Parker said he subsequently — and tardily — filed a notice of appeal against that decision. He did so late, he said, because he erroneously thought the judge’s verdict was a final judgment and that he couldn’t appeal it. When he realized however that he was mistaken, he belatedly requested the appeal.

Now, according to reports, URCA’s lawyer argues that Navette shouldn’t be granted time to appeal due to its “continuous refusal” to “abide” by the appeal process.

As a result, Navette Broadcasting still does not know whether it will be sanctioned for unintentionally not carrying out the appeal process correctly, or if it will be granted more time to state its case.

The post Navette Broadcasting Awaits Day in Court appeared first on Radio World.

Announces procedures, deadlines, and minimum opening bid amounts for the upcoming auction of FM Broadcast construction permits

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There have been plenty of articles written about small single-board computers including in the RW family of magazines (most recently, https://tinyurl.com/rw-pi-2). Getting started with the Pi or Arduino is easy because there is so much ready-to-run software available.

This article begins a series focusing on simple, practical, cost-effective and reliable uses of the Raspberry Pi and Arduino in the broadcast environment.

This first article will serve as a brief introduction for those who haven’t started “Making Pi” yet. Here’s your first warning: The people who make these little systems love bad puns and plays on the device names.

HATS ON!

When the Raspberry Pi foundation released their first system-on-a-chip (SOC) in 2012, they had no idea how overwhelming the response would be. The credit-card-sized computer once meant to be an easy entry point for British students to get into programming and computer science has burgeoned into a whole community of add-on boards (“hats”), screens and extras that people all around the world are using for all kinds of things.

Raspberry Pi computers have ARM processors on them and most Linux distributions that support those processors will run on them. There are also Windows 10 IOT (Internet of Things) embedded platforms that will run on them as well.

The most popular operating system for it by far is Raspbian, which is a derivative of Debian Linux. The Raspberry Pi foundation also has an OS image called NOOBS, which will allow you to install a number of different options on it as well.

Getting started is as easy as buying a Pi, a case and its accompanying necessities, which you might already own, namely a microSD card, a 5V-2A wall-wart-type supply with a micro USB connection, an HDMI cable and a USB keyboard and mouse.

Several starter kits are available that include cases, power supplies and NOOBS already installed on a microSD card. If you already have access to a microSD card, it is simple enough to go to www.raspberrypi.org and download any of the OS images that they have there. There are also details on how to get the image onto the card.

FEEL THE BURN

My particular preference is to use a program called Etcher, which will take any OS image and burn it to flash memory (including USB thumb drives). We’ll have an article about my Linux distribution of choice (DietPi) for Raspberry Pi in a future article.

One of the first real-world uses of the Pi in our studios was as a network AirPrint server to allow wireless device printing. Prior to smartphones and tablets, when we received a new computer, I would have to install print drivers for any network printers, and we had several throughout the building. On top of that, IOS and Android phones and tablets needed a way to print email and other documents in the same way as their computer counterparts. See Fig. 1.

Fig. 1: Our Raspberry Pi happily running a network AirPrint server.

When the Raspberry Pi came along, I saw an opportunity to provide a cost-effective designated computer that would simply provide all of that on the network and relieve my print driver installing duties at the same time. I downloaded the latest Raspbian version that was available and transferred the image to the microSD card.

With power, HDMI, Ethernet, mouse and keyboard connected, I plugged the unit in and let it install itself. The install, as expected, prompted to set time zones, language defaults, etc.

The default user and password is “pi” and “raspberry,” respectively. It goes without saying that network security concerns should motivate you to change the default password. Using the Raspberry Configuration GUI will allow you to make those changes.

You can also enter a terminal, type sudo raspi-config and enter the password, and do it that way. You’ll want to change a number of things including the Raspberry Pi’s host name and also the ability to connect to the Pi via secure shell and VNC by enabling them in the interfacing options. You will probably want to set a static IP address as well.

For the print server, there were several packages that needed to be installed: samba, cups, cups-server, avahi-discover and (if you have an HP printer) hplip. Samba will allow windows network sharing. “CUPS” stands for “Common Unix Printing System” and provides the actual print server packages. Avahi-discover is what allows IOS and Android to find the print server and all of the printers that are available. Finally, hplip as the name implies, supports HP printers.

At the command prompt in an xterm window, you simply enter sudo apt-get install samba cups cups-server avahi-discover hplip and the APT package manager will add those packages to your base install.

Linux has “conf” files and in this case, there are two that may need to be adjusted. Samba’s configuration file is located at /etc/samba/smb.conf and the CUPS configuration file is located at /etc/cups/cupsd.conf. Depending on the way your network is configured, you may need to edit those files. The way to do that at the CLI is to use sudo nano /etc/samba/smb.conf or sudo nano /etc/cups/cupsd.conf. From there, you can scroll through the files to see if there is anything that may need to be changed to suit your network.

The last two things to do before adding printers to the server is to make sure that the “pi” user is an admin for CUPS with the command sudo usermod -a -G lpadmin pi and that the CUPS server is accessible from anywhere on the network with the command sudo cupsctl  –remote-any. Lastly, reboot the pi with the sudo shutdown -r now command.

If you’ve made it this far, the sprint to the finish line is upon us. Now that we have done all of that, we can access the CUPS server locally via a web browser with your setup still connected to a display at http://127.0.0.1:631 or http://static-ip-address-you-gave-the-pi:631 from any device on the network. You’ll enter the site with the user “pi” and the password you supplied earlier. See Fig. 2. Once you click the administration tab, you can begin adding printers. Most network printers will be discovered automatically and you just need to choose them and the CUPS server will typically have a driver that will work for the given printer.

 

Fig. 2: The CUPS server home page.

WE’VE GOT RESOURCES

If you find that a driver is not available for a particular printer, many manufacturers provide drivers in the form of a PPD file. A PPD file (Postscript Printer Description) provides the CUPS server with everything it needs to setup the printer. You can generally find them on the manufacturer’s support page for the printer in question.

Once the file is downloaded, when adding the printer, choose the printer you want to add and when it presents the drivers that are available, you can provide the PPD by browsing to your download folder. Continue this process until you have added all of the printers that you want to be served over your network.

As you are reading this, you might easily fall victim to the belief that this is beyond you.  I can assure you that it will take longer to download the Raspbian operating system image and burn it to the microSD card than it will to get this print server up and running on your Raspberry Pi.

One real advantage is that if it doesn’t work out exactly as I have described, the community of people that have done this very thing and many other things with the Pi is truly massive. This is just one of the ways that a Pi has solved a problem we were having.

When you consider the power savings, the compact form factor and the ability to connect to it without having a monitor by using Secure Shell or VNC, it really makes it a perfect platform for network services like printing.

More to come next time. Email your comments or suggestions for this series to rweetech@gmail.com.

Todd Dixon is assistant engineer for Crawford Broadcasting Company in Birmingham, Ala.

The post Pi for Everyone and Everything appeared first on Radio World.

The author is membership program director of the National Federation of Community Broadcasters. NFCB commentaries are featured regularly at www.radioworld.com.

The holiday season seems to bring many of us around to thoughts of far-away family. Memories of parents, grandparents and elderly neighbors almost universally prompt us to kick ourselves a bit. Mom was right: you should be checking in more.

Those holiday visits are a great metaphor for public and community radio’s bond with its listeners. Just like in our own lives, those people senior to us are influential, even if we are not thinking of them all the time. For radio, where growing audience is the never-ending quest, younger individuals become the gravitational pull for our attention. Yet our foundations come from those people we at times forget.

How can community radio lean in on its older demographic, while remaining inclusive of new, younger listeners?

To be clear, the legacy listener is here to stay — for now, at least. Dozens of surveys, going back years, have indicated that noncommercial radio trends toward older audiences. And though millennials and Generation Z are tuning in too, it is the 40-and-older group that tends to most often listen and donate.

[Read: Community Broadcaster: Will 2020 Elections Doom Radio Fundraising?]

Sensing the growth in older audiences, noncommercial stations do as much as they can to cater to these listeners. Tune in to virtually any community radio station and you will find programs spinning music from the 1990s, 1980s and earlier. Oldies and “classic” music shows are alive and well on community radio in cities across America. Current recently profiled a program positioning its pledge drive around healthy living for retirement aged Americans and beyond.

Such programming may be much more than just a niche or trend, however. Community and public radio listenership and giving is further complicated by the graying of the United States. With the number of Americans over 65 years of age closing in on 50 million, the country itself is at a cultural and political crossroads.

All this sounds like John Coltrane (read: AMAZING) if you are into public and community radio. However, due to the passage of time, the good times will not last. For nonprofits like community radio, dialogs about long-term sustainability and finding innovative ways to get new donors into the fold are ongoing conversations.

With its podcasts, NPR has tapped into the consciousness of younger listeners by delivering something timeless — relevant, insightful, interesting content — in a format the audience likes on a platform they love, smartphones. However, NPR continues to deliver the news and public affairs programming its traditional audience relies on and donates to see continue. This approach seems to be the model of the moment.

For some community radio stations, getting younger listeners is a big priority. But, before fracking their program schedules and putting on EDM, stations would benefit by examining that podcast model. Attracting new audiences is more than doing “something” (such as playing music that managers may assume is liked by these demographics) but about the entire exercise. Who are the hosts? Are they credible? How does the station listen to these new listeners? How is it building trust and relationships? Meanwhile, your station must also balance out the needs of your established donors. How are you messaging your efforts? How are you listening? How are you impressing upon the audience their value while presenting your vision for the station’s future?

This question of audience is a weighty one for noncommercial stations. It is heavy because of the many assumptions we make, especially of community radio, and perhaps ourselves. We want to welcome those youth who will be that station’s base in the coming years. We expect they are interested. Yet the long-time supporters need love too.

The post Community Broadcaster: Generation Shift appeared first on Radio World.

By 1971 my only radio experience was with a carrier current college station, but in my 20-year-old brain I was ready for the big time! When I saw an ad in the paper for a disc jockey I didn’t bother mailing in an application but instead got into my car and headed for a town called Berkey, Ohio.

With a map spread out on the seat next to me in my VW I drove a long way out into the country, passing nothing but farms and fields. Finally I found the address but there was nothing there but a shack, a few cars in the gravel lot, and a tower. I thought this must just be the transmitter site, but seeing no other building I knocked on the door.

A young woman let me in and after I introduced myself she said, “You’re the first to apply for the job. I’ll get the program director for you!” So this little building in a cornfield was a radio station! Shortly a guy about my own age came out to the lobby and told me his name was London. I didn’t realize that he was on the air at the time and had come out to chat while a record was playing. He invited me back into the studio with him where I spent an hour or so. London explained that the call letters were WGLN(FM) and the format was country music. During our brief time together he hired me (Yay!) and I found myself officially employed at my first commercial station, starting the following Monday.

[Read: Adventures in 1970s AM: Curses! Locked Out!]

After I had been working there for a while the wave of euphoria began to wear off and I learned some of the finer details about WGLN. My salary was $1.87 an hour, and even in the early ’70s that was not wonderful. The station was climate-controlled: in the summer we sweated like dogs and in the winter we wore every piece of clothing we owned to keep from freezing.

I don’t want to sound ungrateful, but there were other issues with the station. The bathroom was located in the same tiny closet where we stored the logs and other legal documents, and there was no lock on the door. If someone had asked me if the toilet worked I would have answered “mostly.” Once when I walked down the driveway to the street where our mailbox was located I looked down and saw a snake between my feet. The parking lot was never shoveled in the winter so we parked out on the paved road.

Our owners were two farmers from the equally rural Delta, Ohio. Apparently they thought it would be a swell idea to brand WGLN as “The Home of the Jones Boys,” and they bought a jingle package suffused with that phrase. Musically it was happy hoedown time, and we were stuck with jock jingles for John Paul Jones, Deacon Jones and Davy Jones for example. Each time a DJ left, his replacement had to use the same name jingle as his predecessor. I considered myself a whiz with a razor blade, but there was no way I could edit anything usable out of those jingles, which were reminiscent of the country swing band “Spade Cooley and his Buckle Busters” circa 1935.

I was not a complete stranger to country music but neither was it my métier. When I mispronounced the name of an artist my listeners called in to correct me. And sometimes callers would relate their personal experiences with the stars. One animated fan spoke of meeting Merle Haggard in the restroom of a truck stop in Indiana. “He washed his hands.” Good to know!

A former waitress wanted me to know that Buck Owens was a regular guy, polite and friendly, and he left a big tip. Another brush with greatness. But I learned a lot from people on the phone during my stint at WGLN. When I told a brief story on the air about buying shoes a man called in during the next record to say he didn’t care about all that “happy horse s**t,” suggesting I shut up and play the music. Point well-taken, sir!

While on the air one afternoon with my mic open I heard a tremendous crash of glass which sounded like it came from the roof. I brilliantly ad libbed something like “what was that?” and played a commercial. I found out later that an engineer had scaled our transmitting tower to replace a giant light bulb near the top, and oops, he dropped it.

And on it went for about a year and a half, my time as a Jones Boy. The people at the station were all friendly and helpful, but I knew that this was just a stepping stone on the way to real stardom in AM top 40.

Or so I thought.

Ken Deutsch is living in semi-retirement in sunny Sarasota, Florida and has written for Radio World since 1985. After 34 years he is still learning about writing and radio. His book of these tales is available, Up and Down the Dial. 

The post Adventures in 1970s Radio: How Desperate Was I? appeared first on Radio World.

The authors are senior broadcast engineer for Hubbard Radio and manager of broadcast engineering at Xperi Corp., respectively. WWFD is serving as a real-world testbed for the MA3 mode of HD Radio, which the authors say provides more coverage and less adjacent-channel interference than hybrid MA1.

Over the past 50 years, many AM stations struggled to continue to serve their listeners as they moved into the suburbs and exurbs, far from the stations’ transmitter sites. And the weaker their signals became, the more vulnerable they were to noise from power lines, TVs and other electrical sources.

In Part 1 of this article we explored why today’s AM HD Radio technology hasn’t done much to level the playing field with FM, satellite and streaming services such as Spotify. One major reason is because the current system uses the MA1 waveform. Although that provides HD Radio capabilities such as high-fidelity audio and track data, it may do so in only part of a station’s coverage area.

An HD Radio screen display of WWFD’s PSD.

Another drawback is that MA1’s digital carriers require three times more bandwidth than the analog signal, so they create more adjacent-channel interference — an annoyance that’s among the reasons why people choose alternatives such as FM, SiriusXM or Pandora. By providing a better listening experience for some stations, MA1 actually undermines others.

The MA3 waveform avoids those drawbacks because it’s an all-digital signal, whereas MA1 is a hybrid of analog and digital. MA3 minimizes the interference problem and extends HD Radio’s capabilities to the vast majority of an AM station’s coverage area.

Since July 16, 2018, WWFD in Frederick, Md., has served as a testbed that vendors, broadcasters and the FCC can use to understand how upgrading a station to MA3 affects antenna systems, transmitters and engineering practices. Our previous article described the upgrade process in detail, both from a technical and a business perspective.

This article describes the technique and equipment used to measure power coming out of the transmitter. It also discusses the extensive daytime and nighttime drive-test results conducted in summer 2019, which found that both the core and enhanced carriers are received out to the station’s 0.5 mV daytime contour.

These and other real-world tests suggest that there’s a solid business case for implementing MA3. In fact, even though only about 25% of vehicle radios in the Frederick area can tune in WWFD’s MA3 signal, the station already acquired enough listeners to make its first appearance in the Spring 2019 ratings book. The ratings also suggest that listeners are seeking out WWFD because it offers stereo audio, album artwork and other data. Finally, although WWFD is a rimshot into the D.C. market, some weeks its ratings have exceeded those of 50 kW WFED.

ADDITIONAL DRIVE TEST RESULTS

Qualitative field strength measurements used the station’s existing Potomac Instruments FIM-21 meter, which was checked against an FIM-4100, which is specifically designed to handle the MA3 mode. Drive tests used multiple vehicles’ factory OEM radios.

In the initial drive tests:

• Under ideal daytime conditions, the MA3 primary/core carriers could be decoded down to the 0.1 mV contour, as confirmed via reception reports and drive testing at or near Harrisburg, Pa., Breezewood, Pa., and Cambridge, Md.
• Critical hours propagation phenomena typically reduced reliable coverage to the 0.5 mV contour.
• Nighttime MA3 reception generally followed the station’s nighttime interference free (NIF) contour: Wherever an analog carrier-to-noise ratio of 20 dB is achieved, the MA3 carrier will generally be received. Early evening reception goes well beyond the NIF. As co-channel skywave interference increases during the evening, coverage is reduced to the NIF. In the station’s 2.0 mV contour, in-vehicle reception was reliable, without observed dropouts in either the Frederick urban core or underneath bridges. Reliable urban performance is particularly important for competing with satellite, which often has dropouts even in cities with terrestrial repeaters.

The latest round of drive tests, conducted in summer 2019, showed that the primary/core and enhanced carriers are good out to 0.5 mV daytime contour. This coverage area has a population of nearly 2.8 million people.

This means WWFD’s MA3 capabilities — the stereo audio and album artwork that enable aural and visual parity with FM HD, streaming audio and SiriusXM — are effective for attracting and retaining listeners throughout the vast majority of its service area. By extension, those MA3 capabilities also will help the station attract and retain advertisers.

The core carrier typically dropped out at the 0.1 mV daytime contour, with a few exceptions. For example, at one point while driving east into metro Baltimore, the core carrier failed at 0.2 mV due to electrical noise. However, an analog signal would have been completely unintelligible at this point due to the buzz that few listeners would tolerate.

WWFD AM daytime pattern — all digital.

Terrain also proved to be a factor. For example, in the mountains near Rippon, West Virginia, the core signal failed around 0.25 mV. The reason is unclear, but the result is relatively insignificant because at that point, an analog-only signal would have been very weak. So, most listeners might have abandoned the station at that point anyway.

In the latest round of nighttime drive testing, core and enhanced services were received to half the value of the station’s NIF contour. For WWFD the NIF zone extends to the 10.8 mV contour, and half of that value is 5.4 mV. Co-channel skywave interference appears to limit nighttime service to this contour. The core-only carriers, being stronger, may continue beyond this contour but should not be considered marketable coverage, as interference may cause reception to vary both nightly and seasonally.

WWFD AM nighttime pattern — all digital.

WWFD will conduct a second round of drive testing in early 2020 because propagation conditions are significantly different in the dead of winter. The increased skywave interference probably won’t affect the half NIF (5.4 mV) area, but it could reduce coverage beyond that contour.

THREE POWER MEASUREMENT OPTIONS

All-digital power can’t be measured using traditional analog AM practices. For example, MA3’s peak-to-average ratio is significantly higher than that of analog AM, so the transmitter’s power level meter may read inaccurately. Also, if the transmitter isn’t optimized for MA3 mode, the peak-to-average ratio may be reduced, and a different power level reading may result than if the transmitter had been optimally adjusted.

As a result, the WWFD experiments included identifying a new procedure to verify that transmitters are operating at licensed power when in MA3 mode. Three methods were considered:

• A channel power measurement with a spectrum analyzer on the transmitter’s RF monitor port using an unmodulated carrier at licensed power (verified with the station’s existing base current and common point meters), and verifying the same channel power when the transmitter is placed in the MA3 mode.
• A procedure identical to that above, but instead utilizing a calibrated average power meter.
• Replacing the Common Point current meter and each tower base current meter with a thermocouple-type RF ammeter. (Remote monitoring systems connected to pre-existing meters could then be recalibrated to what the thermocouple meter reads.)

AM stations commonly use transformer-coupled RF ammeters, but they aren’t viable for measuring MA3’s OFDM carriers, which use quadrature amplitude modulation and vary by the type of information sent. Sometimes most or all of the carriers are in phase, which would raise the peak power tremendously. Other times, the carriers could be mostly or totally out of phase with one another, thus reducing the power to zero. As a result, average power is the best metric.

The third technique proved to be the best option, for several reasons:

• A thermocouple-type RF ammeter is a device that many AM stations already have. Those that don’t can purchase one for, at most, a few hundred dollars — unlike a spectrum analyzer. In fact, the WWFD tests used a Simpson 0-15A that was purchased pre-owned for $50. These and other models are widely available online from sellers such as test-and-measurement surplus equipment dealers and even at hamfests.
• These devices also are easy to implement. At WWFD, the Simpson 0-15A was mounted on a fiberglass J-plug inserted into the J-plug between the output of the tower ATU and the tower itself. This is where the current transformer for the base current measurement is located.
• Reading and interpretation are straightforward. After the meter was inserted into WWFD’s system, a baseline reading was obtained by operating the transmitter with an unmodulated carrier with no QAM carriers present. The RF ammeter and current transformer readings should match, which means the station is operating at licensed power. Next, the QAM carriers are turned on, and the RF ammeter reading should be the same as with an unmodulated carrier. If the base current meter is a diode detector, such as a Delta TCA type meter, the reading will be slightly lower.

The WWFD transmitter AUI screen while operating in the all-digital AM mode.

WWFD’s tests used all three measurement methods because a power meter and spectrum analyzer were available. All three methods also proved to be accurate in an MA3 environment. For station owners, equipment manufacturers, consultants and other members of the broadcast ecosystem, the bottom line is that the choice comes down to equipment availability, budget and personal preference. But for most stations, measurement at the transmitter output with a thermocouple-type RF ammeter likely will be the most economical option.

OPTIMIZING ANTENNA HELPS WITH SIGNAL AND LISTENER ACQUISITION

Since Part 1 of this series published in October, the daytime antenna system was further optimized using a design provided by Kintronic Labs. The goal was to shift the day pattern from its upward position to the optimal load for the transmitter (“cusp left”), as well as to provide additional broadbanding of the antenna system. This was achieved by replacing the capacitor in the very long transmission line with a second T network.

This change provided several benefits, starting with presenting the transmitter with the best possible load (also referred to as “Hermetian symmetry”), as well as tuning out the transmission line’s inductance. Additional benefits were surprising. Radios were able to acquire the core digital signal faster: within one frame (1.5 seconds). When the digital signal was lost (such as under bridges or near major power lines), it recovered faster.

For stations that decide to implement MA3, these kinds of network changes are worth considering because they improve the listening experience. The less frustration and annoyance that audiences encounter, the less likely they are to tune away. Faster acquisition times help them find a station in the first place as they’re casually tuning around. Large, loyal audiences attract more advertising revenue, which helps make the business case for upgrading to MA3.

Another potential business factor is the possibility of adding HD2 on MA3. This could be particularly valuable for AM stations in smaller markets by providing an additional revenue stream. That income could further offset MA3 upgrade costs. The license fee also will be waived for stations that turn on MA3 full-time.

MA3 WILL HELP REVITALIZE AM

Each AM station has its own set of marketplace considerations and business challenges, which is why there can never be an industry-wide silver bullet. MA3 is no exception to that rule. However, it will be a viable option for many stations.

While an AM station with an existing, profitable analog audience is not likely to be among the first to switch to digital, it should be noted that analog AM broadcasting, in general, is not a growth medium. In-home listening is migrating to streaming devices such as smart speakers, and in-car listening of terrestrial analog broadcasts is being challenged by the new options offered in-dash.

Trends in receiver designs seem to be converging around “tuning” by visual metadata: specifically, a thumbnail preset. A receiver of the future will likely scan the bands for available content and display the available options. When pressing an icon for a favorite station, it may not be immediately obvious whether the source is AM, FM, satellite or a stream. AM stations must be digital to transmit the necessary metadata and achieve the required audio fidelity. All-digital AM is likely to be one option “under the hood” of delivering audio content to future receivers.

For the immediate future, AM stations converting to all-digital achieve aural and visual parity with other services in the dash: FM HD, satellite and streaming. Additionally, having a desirable product with a pleasant user experience in the dash will cause car manufacturers to take notice and include AM (and FM) HD in their standard offerings.

It’s important to note that with the possible exception of electric vehicles, when consumers get AM HD, they get analog AM, too. That “package deal” should benefit legacy stations by keeping the medium in the dashboard. It costs money to keep AM in the car (in terms of hardware and noise-suppression techniques), but by going digital, broadcasters on the “senior” band will cause receiver manufacturers to take notice by showing that AM can be a growth medium, as well. In short, going digital reinforces the presence of AM in the car.

Dave Kolesar, CBT, CBNT, recently recieved the Radio World Excellence in Engineering Award for 2019–2020.

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

 

WWFD: A Station Overview

Owned by Hubbard Radio, WWFD runs an adult album alternative format on 820 kHz. It operates 4.3 kW non-directional during the day and switches to a 430 W two-tower array at night.

WWFD also has a 160 W translator, W232DG, on 94.3 MHz. Most WWFD listeners migrated to the translator after it signed on in July 2017, which made it feasible from a business perspective to replace the analog carrier with MA3 on an experimental basis.

The FCC granted Hubbard a one-year STA to operate WWFD in MA3 mode, a switch that took place on July 16, 2018. Getting to that point took a lot of time, effort and collaboration with Kintronic Labs and Cavell, Mertz and Associates for the antenna system, and Broadcast Electronics, Nautel and GatesAir for the transmitters. Xperi Corp. lent its expertise to set up the digital transmitters, and to verify the operation of the antenna system. The STA has since been renewed.

The post Real-World Tests Make Business Case for MA3 appeared first on Radio World.

WorldDAB has published the first version of its Aftermarket Devices Guidelines.

Designed by the WorldDAB Aftermarket Devices Working Group, the purpose of the document is to improve the user experience of aftermarket devices, including those for DAB+ digital radio.

Intended for manufacturers, WorldDAB says these guidelines are based on WorldDAB User Experience Group research and incorporate “allowances and changes in line with the nature of AMDs.”

Featuring directions on domains in relation to AMDs, including for instance, user interface; device connection; functionality; power; service lists; car display; service following and antennas, the document provides a foundation for manufacturers of aftermarket devices and adaptors. WorldDAB plans to update the guidelines as necessary based on market developments and future improvements.

“These Aftermarket Devices Guidelines were developed to help manufacturers better understand how to integrate DAB+ digital radio devices into vehicles that are already on the road,” said Jørn Jensen, retiring chairman of the WorldDAB Aftermarket Devices Working Group.

“The aftermarket sector has seen a significant increase in demand over the last few years. More drivers are looking to bring the extra choice and better quality of DAB+ into older cars, which do not have digital radio as standard. These guidelines were created to help achieve this in the best possible way.”

The Aftermarket Devices Guidelines is available for download here.

The post WorldDAB Releases Aftermarket Devices Guidelines appeared first on Radio World.

Start off the new year off right. Now available, Scott Fybush’s famed Tower Site Calendar for the year 2020. As always, each month features a radio broadcast tower in a gorgeous setting.

This 19th edition takes a trip across the pond adding a tower in the United Kingdom.

Calendars are $20 plus shipping, and tax if you live in New York state. For info contact Lisa Fybush or call 1-585-442-5411.

The post Towering Calendar appeared first on Radio World.