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Unspinning the LPFM Threat

Everyone saw this coming. The NAB, aka the National Association of Existing Broadcasters, came out with guns blazing against LPFM upon the first inkling that thousands of new FM stations could be shoehorned into the existing FM band

Everyone saw this coming. The NAB, aka the National Association of Existing Broadcasters, came out with guns blazing against LPFM upon the first inkling that thousands of new FM stations could be shoehorned into the existing FM band. Many more stations could have been part of the LPFM rollout, especially in the coveted large population centers if relaxing third-adjacent-channel spacing restrictions had been adopted.

After strong-arming congress and the FCC with its own studies showing potential widespread interference from third adjacents, the NAB succeeded in curtailing the potential for the new LPFM service when it was finally launched in 2000. Would you expect anything less from one of the country’s most powerful trade associations, protecting the interests of the status quo?

About 300 new LPFM stations are now on the air, with another 700 CPs granted. LPFMs have made little impact on the industry so far. Practically all of them are licensed by local government, educational, religious and other community groups with narrowcast programming appealing to tiny audiences. But the ongoing efforts to expand LPFM opportunities by lobby groups like the Media Access Project may finally be paying off.


Enter “the Mitre Report,” an FCC-commissioned study to decide whether LPFM stations on third adjacents serving the same area would actually cause real or significant interference. While the methodology contained flaws and offered only limited field measurements and/or evaluation of real world scenarios, the conclusions were predictable and reasonable.

The commission agrees and has now reversed itself in proposing to drop the third-adjacent restriction for LPFM. Look for legislation to be introduced in the coming weeks and eventually adopted to enable more LPFM assignments in the future.

I originally defended the NAB position in a column back in 2000 about LPFM.

Almost nobody opposed the original LPFM concept that envisioned a valuable new broadcasting service for small, underserved communities that would enable a local community group to build an affordable FM station that served their public interests and welfare. But, I argued, with an already congested FM band in most population centers, plus the apparent need to protect the FM guard-band allocation scheme for HD, why make the congestion and interference potential even worse for both existing broadcasters and the audiences they are trying hard to serve? Especially when the most vocal LPFM advocates wanting these stations seemed to be commercial radio misanthropes, pirates, ex-pirates and radio owner wannabees, mostly with eclectic, radical and self-serving agendas. LPFM ownership rules thankfully locked out that crowd.

As things have turned out, the LPFM CPs granted so far have gone to small governmental or educational community-based groups, who want very much to provide a public service on the radio in their local areas.


I’m beginning to think this service deserves a real chance to succeed. After all, providing an opportunity for responsible voices to be heard that represent diverse and underserved interests in our society is still an embedded principle of American democracy. But the commission will have to continue doing a careful job qualifying and granting CPs to legitimate and local applicants.

My biggest lingering fear about LPFM is rules compliance and enforcement. With shrinking FCC field operations budgets, it will be mostly up to existing broadcasters to shepherd and police their little LPFM brothers on the band. The urge to run higher power than authorized or excessive modulation for better coverage could prove tempting.

On balance, a greater good can be served here over the risk of small pockets of increased potential interference. But the only way LPFM could do a better job fulfilling its original mandate in population centers is by relaxing the third adjacent protections. The widespread use of modern receivers makes this feasible.


Did the NAB intentionally mislead congress and the FCC about the potential for interference if third-adjacent protection was dropped? It’s almost like asking did the Bush administration intentionally mislead congress and the country about WMDs in Iraq before the war. There certainly was evidence of the previous use of WMDs in specific isolated cases. And it can be shown that interference may affect some existing stations in limited areas near new third -adjacent stations in specific isolated cases.

Predicting real interference in the crowded spectrum of FM broadcasting is not all that difficult nowadays with computer modeling tools, coupled with real world simulation testing and evaluation. Unfortunately the FCC now says it doesn’t have the budget to do any more field testing. But the exercise is both science and art. Common sense and historical perspective are needed here to unspin this controversy.


The FCC adopted its basic channel allocation spacing plan for the FM service back in 1964. The state of the art in both transmission and receiver technology was primitive compared to performance capabilities we have today. Improvements have grown by quantum leaps.

Better receiver front-end designs with improved selectivity and overload immunity coupled with digital synthesizers, tighter IF bandwidths and noise reducing decoders have allowed thousands of stations on second- and third-adjacent channels to serve common areas.

It doesn’t take a radio engineer to realize that most populated areas are home to many second- and third-adjacent stations that have been serving the public for a long time with only minimal complaints of interference. While most of these signals are low power, coming from translators and boosters, many in the congested areas of the northeast, Chicago and L.A. are full-power operations.


Grandfathered short-spaced stations everywhere have been serving large audiences all these years with the blessing of the NAB and the commission. There are even some stations on first-adjacent channels that serve overlapping areas in extended metro areas. If existing stations continue to thrive in this environment, it’s not unreasonable to expect that new LPFM third-adjacent stations should be able to coexist peacefully.

Relaxing the third-adjacent restriction will hardly turn the coverage of full-powered stations into Swiss cheese, as a few opponents have suggested. Adding a few hundred additional LPFM channels for larger population centers will be a small blip on the allocations radar screen for a band nearly fully populated already in many markets.

If LPFM had been proposed 40 years ago along with relaxation of third-adjacent protection, it would have been a laughable non-starter. Most FM radios didn’t even have AFC locking back then. With fragile front-ends and IFs broad as barn doors, allowing for plenty of protective channel spacing was important to allow the fledgling FM service to attract and hold listeners.


It’s not too hard to see how LPFM antagonists at the NAB and the FCC found a friendly ally in the spacing rules when they went looking for technical justifications to thwart the adoption of relaxing the third adjacent into law. What they neglected to understand fully or convey to non-technical congressmen voting on the issue was that the aging rules do not address or allow for present practices or the evolution of better technology.

As much as the NAB and those who still oppose LPFM expansion want to pick apart the Mitre report as flawed or incomplete, they cannot escape the reality that the FM band already supports thousands of less than fully spaced stations that cover common areas and serve their listeners quite well. Sorry, Eddie. The genie you’ve been protecting all along for your friends is already out of the bottle. Everyone can see it.

There is one other no-spin truth about LPFM that will actually benefit existing broadcasters. As it grows and develops, LPFM can serve as a fertile training ground for up-and-coming broadcasters who now have a very hard time breaking into the business. Where will the next Rush Limbaugh, who might be a teenager today find an entrance into our industry?

Some argue that with so many cookie-cutter voice-tracked and satellite fed automated stations, radio is snuffing out its ability to employ and train new and aspiring talent. LPFM can help to counteract that trend and will serve as a natural onramp to the big leagues.