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A young chief engineer who knew a lot more about computers than transmitters and analog audio systems recently asked me for help in tracking down on-air distortion that had affected his mom-and-pop station for some time.

The station did have on-air distortion. It was not terrible, just bad enough to notice, though the longer you listened, the more it irritated — a real turnoff for Time Spent Listening.

It sounded to me a bit like the audio was going through an amp with bad power supply filters, and it had a raspy edge on voice. But identifying the source of the problem by ear was difficult.

This was an AM station that had an FM translator mounted on the hot tower, a situation that can present its own set of challenges. The distortion was evident on the FM. But a critical listen revealed that it was present on AM as well!

This pretty much ruled out my thought that high RF at the tower was being rectified on the audio input to the translator and showing up as audio distortion. So it was time to take a look at the audio chain.

Pretty straightforward: Program was being delivered from the studio miles away, with digital uncompressed audio sent over fiber. It sounded good going in, and it sounded good coming out. Yet the on-air product definitely was distorted.

The audio was fed to the FM via a buried 1,000-foot cable to the tower. That line was driven by a pair of old super-quality Western Electric 111C repeat coils set up for 600 ohms in and 600 ohm line out with center tap grounded — the perfect way to send audio in an RF field. This arrangement no doubt had been set up by a previous chief who knew the magic of repeat coils for long lines.

Audio from the codec was connected to a Broadcast Tools switcher, then to the program line that fed the AM processors and the FM line to the tower.

I grabbed a handheld oscilloscope — something the young chief had never seen — and pulled the output connector from the switcher. I gave it a look on the scope with a 600-ohm load, and it showed nice clean peaks at about +8 dBm — looked good, sounded good.

I plugged it back in and bridged the line with the scope. Aha! The scope showed clipping with the peak levels closer to +3 dBm and a definite ceiling.

There was trouble here, but why?

Audio level on the coils was well under the +30 dBm (1 watt) design limit for the rugged four-pound 111Cs.

Still searching for the problem, I spotted a couple of black boxes where the cable leaves the building. These were Grommes~Precision TLS lightning suppressors.

When I looked up their data sheet, things started to make sense.

The TLS contains multiple stages of lightning protection. This unit is designed for protection of audio paging circuits with an RMS audio level of 1 volt. On a 600-ohm line, 0 dBm (1 milliwatt) is .774 volts, so with a level of +8 dBm (1.94 volts) the line level was crossing the clamp point for the TLS.

While the spec sheet shows a switching to ground level of 25 volts, the unit starts clamping just over one volt.

While finding this problem was a bit of a challenge, fixing it was a snap. With the drive to the line reduced to –3 dBm (.5 volts) on the PPM meter, things sounded great.

Another solution would have been replacing the TLS units with LLS models that have a pass rating of 6 volts (17 dBm), which is better suited for broadcast levels. But we work with what we have.

Now you might ask, why did the AM sound bad if the problem was on the FM stereo pair?

The Broadcast Tools switcher derives its mono output (used by the AM) by passive combining of L+R internally from the stereo output. So if the stereo line gets clamped, so does the mono line!

I suggested and installed a set of 1000-ohm buildout resisters on the output of the switcher, the better to isolate the FM feed, just as a precaution. With the 111C coils set up for center tap ground, the TLS might not have been needed at all; but better too much protection than not enough.

With the elimination of the distortion, the station was able to process a bit harder, increasing the loudness while improving the sound quality — a win-win for sure.

While I was there I couldn’t resist teaching my young friend to reduce the AM modulation peaks from 130 percent positive (yikes!) 100 percent negative, to about 90 percent symmetrical. He heard the difference and agreed to keep it that way.

The takeaway here is simple: Read spec sheets, and know how adding devices will affect your overall sound.

My assist call also underlined a growing problem in broadcasting. “Us old guys” know analog audio and issues peculiar to AM. The new “engineers” are not getting that knowledge, learning only about digital and computer networks. I hate to say it, but institutional knowledge is dying as more of us become silent keys.

Solution? Us old guys need to take every opportunity to reach one, teach one.

The author is chief engineer and owner of WGTO Cassopolis, Mich., and W246DV South Bend, Ind. Read more of his past articles.

Share your own tech tips or stories about how you solved a problem. Write to radioworld@futurenet.com.

The post Distortion Detective: The Case of the Irritating Audio appeared first on Radio World.

The pages of RW Engineering Extra are where the finest engineers hang out! Engineers like Stephen Lockwood, Cris Alexander, Jeff Keith and Jeff Welton, whose latest stories you’ll find here.

The FCC recently adopted new rules regarding RF human exposure limits. Lockwood, president of Hatfield & Dawson Consulting Engineers, discusses what radio engineers should know about them.

Keith of Wheatstone writes that there are many tools available to help quantify the performance on your air chain. Good Engineering Practice doesn’t have to cost a lot of money.

Alexander reminds us not to overlook the possible simple solution when we’re confronted with a problem. And Jeff Welton explains the beauties of ferrite toroids.

Read it here.

The post Inside the Oct. 20, 2021 Issue of RW Engineering Extra appeared first on Radio World.

An AM/FM combo, along with an FM translator, serving a small Ohio municipality is being spun.

That could explain the buzzards flying around the building, if you will.

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From our People News page: Katz Media Group promoted Scott Porretti to president of Katz Digital Audio, a newly created position. He had been executive vice president.

“Porretti, a veteran of Katz, who is uniquely qualified for his expanded role, will continue to oversee all Katz Digital Audio offerings, manage relationships with an expansive roster of publishing and technology partners, and further the growth of podcasting and programmatic digital audio on behalf of current and new partners,” the organization announced.

Porretti has held several management positions there including senior vice president of Katz Radio Group and vice president manager of the Katz New York office.  In 2014, he was named senior vice president of Katz Digital and in 2018 was promoted to executive vice president of Katz Digital.

It said he led its digital team in making “substantial strides” to strengthen its internal technology and systems, and that he is spearheading the rollout of Katz Intelligence Manager, a proprietary audience system for the digital audio marketplace.

He will continue to report to Mark Gray, CEO of Katz Media Group.

Gray highlighted Porretti’s audio industry knowledge, team leadership style and “extraordinary vision in this marketplace.”

The post Porretti Is Named President of Katz Digital Audio appeared first on Radio World.

“After a lighter-than-normal content slate in Q1 and Q2 due to COVID-related production delays in 2020, we are seeing the positive effects of a stronger slate in the second half of the year.”

That’s the collective assessment of Netflix co-CEOs Ted Sarandos and Reed Hastings, CFO Spence Neumann, COO and Chief Product Officer Greg Peters, VP of Investor Relatons/Corporate Development Spencer Wang, as the OTT giant released its third-quarter earnings report following Tuesday’s Closing Bell on Wall Street.

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Spotify said its Megaphone podcasting platform is now up and running in Germany, Spain, Italy and France.

The company said podcast listening in Europe now reaches 20 to 30% of internet users in those markets. It cited a report from eMarketer. Further, it said Euro podcast ad spending is expected to grow more than 50% by 2023, according to IAB Europe.

[Related: “Spotify Expands Audience Network”]

Megaphone launched six years ago and was acquired by Spotify less than a year ago.

Spotify said about 30% of the top 200 shows on Spotify and on Apple are hosted on Megaphone.

The platform provides tools for creating, measuring and monetizing podcasts.

The post Spotify Megaphone Is Open in Four Euro Countries appeared first on Radio World.

What is the role social communities play in influencing purchase decisions?

WARC, in partnership with TikTok and Publicis Groupe, came together for a just-released study that helps answer that question. Their work outlines what they say is “the huge potential for brands to engage with audiences and increase unplanned purchases by narrowing the funnel between product discovery and purchase.”

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Starting Monday (10/25), a pair of ABC affiliates in the Lone Star State owned by The E.W. Scripps Company will have a new VP/GM.

It’s an individual whose most recent TV industry role was as President/GM of the NBCUniversal-owned Telemundo affiliate serving Denver.

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There are several new social media accounts at the Federal Communications Commission. This is not in itself unusual, but these accounts have been set up by the FCC Office of Inspector General.

Its goal: “to aid in our mission of detecting and preventing fraud, waste and abuse, and promoting economy, efficiency and effectiveness in the operations of the FCC.”

It now has a presence on Twitter, LinkedIn and Facebook. The first tweets on the OIG Twitter account were sent in late July. The current inspector general is David Hunt.

In a statement, the FCC OIG noted that it is a small office with fewer than 50 full-time employees that “nonetheless is responsible for the oversight of FCC operations and billions of dollars in funds administered through various FCC programs.”

It said recent Covid-19 relief legislation provided additional billions of dollars in funding to the FCC.

“With the expectation that some of these emergency appropriations may become permanent, our need for assistance from the public to help us ensure this money is appropriately disbursed, is at an all-time high.”

The office said it hopes to increase its visibility of our office through social media, expecting that people or entities with helpful information “will come forward to assist us in furthering our mission.”

The OIG encourages people to call 888-863-2244 or 202-418-0473 or email hotline@fcc.gov if they suspect FCC-related fraud, waste or abuse.

The post FCC Inspector General Launches Social Accounts appeared first on Radio World.

Ed Woloszyn, the General Manager of dual CBS/Fox affiliate KEYC-12 in Mankato, Minn., recently died following a brief cancer fight.

Now, Gray Television has chosen the individual who will take over the station’s leadership role. It’s a woman who has been News Director for a former Quincy Media, Inc., property in Rochester, Minn.

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