Category Archives: AM

Peter Tannenwald asks, “Are we really ‘revitalizing’ AM?”

(Source: RadioWorld via Bill Patalon)

On AM revitalization, Peter Tannenwald asks, Are we really “revitalizing” AM, or are we walking around in circles?

Late on Friday, October 5, the Federal Communications Commission (“FCC”) released a Second Further Notice of Proposed Rulemaking in a five-year ongoing effort to “revitalize” the AM radio broadcast service. The new proposals continue a trend toward allowing higher power operation by smaller stations, by reducing nighttime signal protection for some 60 Class A AM stations located in the continental United States and 16 stations in Alaska. The end result would be less wide area coverage and more local radio service to the public.

To understand why the FCC is considering this action, it helps to understand a bit of the science behind AM signal propagation. AM radio signals travel through both the ground and through the air. At night, the airborne signal component (“skywave”) is reflected back to the earth from the ionosphere — a layer of the atmosphere extending from about 50 to 600 miles above the earth’s surface. The reflected signals may come back down to earth hundreds, if not thousands, of miles away from a station’s transmitter. Class A AM stations — formerly known as “clear channel” stations (no relation to Clear Channel/now iHeartMedia) — are powerhouses, transmitting with 50 kilowatts of power 24 hours a day – 200 or more times the power of the smallest AM stations.

[…]Signal reflection doesn’t work so well during the day, so the FCC has allowed other stations to occupy the Class A frequencies in other markets. But those stations have to curtail power during “critical hours” (two hours before sunrise and after sunset) and often have to reduce power to nearly nothing or shut down altogether at night. In today’s 24-hour-a-day, nonstop world, not being able to reach an audience at night is a losing proposition; so the FCC has yielded to constant pressure over the years to allow more power and longer hours of operation by those “other” stations, at the expense of long distance reception of Class A signals.

Now the FCC is proposing to go further, rolling back some previous restrictions on non-Class A AM stations and perhaps eliminating whatever remains (and it’s not much) of the protection of far-away reception. Under the proposals, which are sufficiently complicated that you should talk to your engineer if you really want to understand the details, Class A AM stations would be protected only within a higher strength signal contour (and so within a smaller area) than they are now; at least some, if not all, skywave protection would be eliminated.[…]

Click here to read the full article at RadioWorld.

A great resource for finding over-the-air stations in the US

13 Replies

Yesterday, a friend asked about tips for finding local radio stations throughout the US. His goal was to identify stations that he could then load into his WiFi radio and stream from abroad.

Of course there are always online radio station aggregators like TuneIn, but often you either need to know the station ID or name in advance to perform a search. Not all stations can be recalled with a geographic search either–especially if it’s a small local station that doesn’t market their online stream.

SWLing Post contributor, Gary Donnelly, recently shared the following searchable FCC database that lists all licensed stations on the air.

Search for:

Gary found this comprehensive database a great way to sniff out smaller LPFM and community stations to DX on FM and AM.

Post readers: Are there other resources you use to find over-the-air stations throughout the world? Please comment to share your links and tips.

FCC might reduce AM clear channel power

11 Replies

(Source: Tom Taylor Now)

Are the protected night signals of monster 50,000-watt AMs “an anachronism?”
And is the FCC poised to do something that will frustrate late-night DX’ers? The Commission tries again to balance the role of Class A signals like KMOX St. Louis/1120, designed to serve listeners hundreds of miles away, with the desires of local AMs. The “skywave” debate is decades-old – but particularly urgent now, given the rising noise floor from all kinds of interference. The Commission just issued a “Second further notice of proposed rulemaking,” noting the rise of “FM stations, satellite radio and other media.” The first notice drew “a voluminous and diverse set of comments,” with some pointing out that “AM skywave service is sporadic and unreliable, often subject to overwhelming environmental interference, and unlikely to consist of programming tailored to the needs of distant communities.” But then there are questions about hurricane and other weather/safety warnings. In this notice, the Commission has ideas about changes to daytime, “critical hours” operation after sunrise and before sunset, and “nighttime hours.” One observer tells this NOW Newsletter says that cutting through the thicket of details, “It’s clear that there will be a further reduction in protection to the clear channel Class A stations, particularly at night. The main questions are how much protection they will retain.”

Click here to read at Tom Taylor Now.

All-digital AM HD: WWFD’s experiment is attracting attention

16 Replies

(Source: InsideRadio via Ulis K3LU)

All-Digital AM Grabs Automakers’ Interest.

The fate of AM radio in the car dashboard may pass through Frederick, MD. That’s where the latest experiment on an all-digital AM signal is taking place, on Hubbard Radio’s adult alternative “The Gamut” WWFD (820). The project, in conjunction with digital radio developer Xperi and the National Association of Broadcasters’ PILOT program, is already generating interest from carmakers in the U.S and around the world.

The Federal Communications Commission in July approved a proposal to allow WWFD to turn off its analog signal for the next year while remaining an all-digital operation. The aim is to use the real-world environment to conduct experiments designed to improve the all-digital AM service.

WWFD has 4,300-watts day (non-directional) and 430-watts night (directional) and the company proposes to operate with roughly the same output when it goes digital-only, 24-hours a day. Dave Kolesar, Hubbard’s senior engineer overseeing the project, said it’s an ideal station to use for a test case since it’s non-directional by day and directional at night.[…]

The switch has already been flipped and Xperi senior manager of broadcast technologies Mike Raide said preliminary results are encouraging. “We haven’t had any problems with OEM receivers,” he said, noting he drove 70 miles from the transmitter site and still picked up WWFD without any problem. In fact, one DX listener in the Pittsburgh area, roughly 300 miles away, said they were able to hear the station during the daytime. “That’s a testament to how robust all-digital is,” Raide said.[…]

“At a time when we’re all hearing rumors about car manufacturers cutting AM from their factory offerings, something like this could come along and show the auto manufacturers that AM still matters and AM has a digital solution as well,” Kolesar said.[…]

Click here to view the full article at InsideRadio.

In August, I received a strong lock on WWFD in neighboring West Virginia via my car’s built-in HD receiver. The next day, I made this short video of my reception on the Sangean HDR-14 (read review here) in neighboring Germantown, Maryland:

I found that WWFD covered the DC metro area quite well.

Post readers: Do you believe, as this article implies, that AM HD could revitalize the band?

Are we entering the age of atomic radio?

5 Replies

(Source: arstechnica via Scott Schad)

A new antenna using single atoms could usher in the age of atomic radio

The team tested their device by recording themselves singing “Mary Had a Little Lamb”

JENNIFER OUELLETTE

In the 1950s, atomic clocks revolutionized precision time-keeping. Now we may be on the verge of so-called “atomic radio,” thanks to the development of a new type of antenna capable of receiving signals across a much wider range of frequencies (more than four octaves) that is highly resistant to electromagnetic interference.

An antenna is typically a collection of metal rods that pick up passing radio waves and convert their energy into an electrical current, which is then amplified. One might argue that the good old-fashioned radio antenna has served us well since the dawn of the 20th century, so why do we need anything to replace it?

According to David Anderson of Rydberg Technologies, those antennae are wavelength-dependent, so their size depends on whatever wavelength of signal they are trying to measure (they need to be about half the size of whatever wavelength they are designed to receive). That means you need antennae of several different sizes to measure different radio frequencies.

Anderson is a co-author of a new paper posted to the arXiv describing a novel alternative to conventional antennae, based on vapor cells filled with a gas of so-called “Rydberg atoms.” That just means the atoms are in an especially excited state, well above their ground (lowest-energy) state. This makes them especially sensitive to passing electric fields, like the alternating fields of radio waves. All you need is a means of detecting those interactions to turn them into quantum sensors.[…]

Read the full article at arstechnica.

Click here to download the research paper: An atomic receiver for AM and FM radio communication (PDF).

Hurricane Florence’s toll on radio stations and cell services

Radio World: “Who’s Got the Biggest, Meanest AM Flamethrower?”

2 Replies

(Source: Radio World)

More broadcasters than you might realize are helping keep the ionosphere warm (and the power companies happy)

In the May 9 issue of Radio World, I reported on a recent power upgrade at TWR’s Bonaire AM facility that brought that station close to the half-megawatt level (440 kW), allowing the station to make the claim that it is the most powerful medium-wave (MW) operation in the Western Hemisphere. After the dust settled, I thought it might be interesting to poke around a bit in the data available to see if they have a close (or even not-so-close) contender for second place for this title.

With only a few exceptions, U.S. stations have been capped at 50 kW since this power level was authorized by the Federal Radio Commission in the late 1920s. Powel Crosley Jr.’s WLW 500,000 kW 1930s “experimental” operation is one very well-known example, as it received a lot of publicity during the five years or so during it operated before being powered down. However, there was another much less well-known superpower operation during that period (it actually beat WLW to the punch by putting 400,000 Watts on the air about three years before Crosley was ready to belt out his hundreds of kilowatts).

[…]Surprisingly, there is one U.S. AM station that has the necessary paperwork and equipment to operate at 100 kW full-time. However, it’s not listed in the FCC’s AM database. I’m referring to the VOA’s “Radio Martí” in Marathon, Fla. which operates on 1080 kHz.

The VOA station (it sports no call sign) appears to be the only operation in its class in the U.S. and Canada, but it if you cross the border into Mexico, you’ll find “muchas estaciones de radio” that emit lots more than a puny 50,000 “vatios.”[…]

Click here to read the full story at Radio World.