The FCC has launched a Notice of Inquiry looking toward the creation of a new “C4” class of FM broadcast station, with an effective radiated power (ERP) limit of 12 kW.

Although recent press reports suggested that the proposal was getting nowhere at the FCC, someone must have sent in a turn-around specialist, and the C4 idea has now been put out for public comment. The proposal is very important to many Class A stations, now limited to 6 kW ERP, that have difficulty competing with more powerful neighbors. If you were a 6 kW David in a market full of 50 kw or 100 kw Goliaths, you would likely perk up fast at the opportunity to double the power in your slingshot.

To some extent, the FCC is for now only is kicking the can down the road, as the proceeding is only an inquiry and not a rulemaking. It won’t result in actual new rules until a subsequent rulemaking proceeding is initiated and concluded. Moreover, the FCC suggests that its enthusiasm about creating a new opportunity for FM improvement is tempered by concern over the potential impact on FM translators and that might be displaced from their channels if full power stations are allowed to upgrade. In other words, how many stations might benefit compared to how many might be hurt?

C4 enthusiasts should first note that the FCC has proposed to allow 12 kW ERP only in Zone II. The country is divided into three geographic zones: I, I-A, and II. Zone I cuts a swath from Michigan and Wisconsin eastward across to New England. Zone I-A includes most of California and all of Puerto Rico, and the U.S. Virgin Islands. If your station is in the densely populated northeast or California, you are not in the game so far, although we would not be surprised to see stations in those areas file comments saying “no fair leaving me out.”

The present FCC rules provide for several FM station classes. The original A, B, and C classes created when FM was born have morphed into A, B1, B, C0, C1, C2, C3, and C as the FCC has refined its rules over the years to try to fit more stations into the finite 20 MHz of FM radio spectrum. Each class has its own power and antenna height limitations. Class A stations are the smallest, with up to 6 kW ERP. Class C stations are allowed 100 kW. The other classes fall in between.

The FCC’s Rules require minimum physical distance separations between stations operating on the same or closely adjacent frequencies. The idea behind uniform distance protection is to allow stations to be built with less than the maximum power and height for their class and be able to expand up to the maximums without any other station being an obstacle. But whenever there is a rule, there is always someone who wants a waiver. Because some stations wanted to move to locations that did not meet the required separations, the FCC adopted its Rule Section 73.215, under which a station may voluntarily relinquish its mileage separation protection (becoming “short-spaced”) and move to a place where it receives protection only against predicted, calculated interference. Rule 73.215 status usually caps a station’s own future expansion, while not precluding expansion by other stations that did not elect 73.215 status.

If the FCC creates a C4 station class, it will have to develop new mileage separation requirements. It will also have to decide whether to open up more room for C4 stations by downgrading the class of existing stations that operate with less than the maximum facilities for their class – something it has done to accommodate new station classes in the past. The FCC asks whether it should downgrade stations only on request by someone trying to fit in a new station or should automatically impose downgrades on all stations that are in practice operating with facilities at or below the maximum for a lower class — something it has done before.

Currently, FCC Rule 73.215 status applies to only those stations that voluntarily request it for their own benefit. The FCC now invites comment on a new approach that would permit stations seeking to upgrade to impose Rule 73.215 status involuntarily on other stations. If that happens, the FM band may start to look more like the AM band, where all stations are assigned frequencies based solely on interference calculations, approval of facilities improvements is often difficult to obtain, and station service areas are often small.

It is likely that secondary services, including FM translators and Low Power FM (LPFM) stations, will raise their eyebrows over any proposal that would saturate the FM band more densely with full power stations. Full power stations take priority, and many secondary stations have been displaced in the past by full power upgrades. Sometimes they have been able to find a home on a new channel, other times not. The FCC has invested a great deal of effort over the past two decades promoting the growth of LPFM and more recently promoting the use of FM translators to enable AM stations to improve their audio quality and to stay on the air at night even if their AM signal has to shut down. There is some discomfort with the idea of helping one group of stations improve if the result would stomp on other stations and wipe out much of what the FCC has recently accomplished. On the other hand, the FCC does not want to upgrade translators or LPFM stations to primary status, as that change would necessitate more stringent engineering constraints that would reduce the number of those stations that can be authorized.

Finally, we are hearing from the FCC something that at least this author thinks has been coming for a while: whether the constant cramming of more stations into a finite frequency band will ultimately degrade the entire band with interference, to the detriment of all stations. The FCC asks whether we are perhaps coming to a “tipping point” in terms of eroding the benefits that have come from efforts to satisfy the seemingly insatiable demand for radio licenses, which continues despite all the other distribution media that have recently evolved.

The C4 proceeding is likely to generate just a wee bit of controversy, with significant groups weighing in on each side of the issue. The deadline for comments has not yet been announced. Watch for updates.