Whether an FM antenna that is purportedly nondirectional should be reclassified as a directional antenna, requiring that the station which uses it back down its power, was a question that the FCC addressed a few months ago in a case we wrote about here.  There, the FCC concluded that the antenna was in fact designed to radiate in certain directions far more than predicted from an omni-directional antenna, ordering the station that was using the antenna to show cause why it should not be forced to back down its power to protect stations in the direction of its maximum radiation. In a decision released yesterday (available here as a Word document, the PDF link appears to be broken) addressing the response to the Show Cause order – in a very quick action on a contested matter like this – the FCC rejected the showing offered by the licensee to defend its purported nondirectional antenna and ordered the station to reduce power. I was speaking at Georgia Association of Broadcasters annual convention this weekend, and the March decision came up in the discussion, which was of great interest to those interested in technical issues for FM broadcasters. Yesterday’s decision will certainly only fan the flames of discussion going on within the industry about this issue.

As we wrote back in March, the FCC initially found that the Texas station in question (KFWR) had effective radiated power levels almost three times those that would be predicted by its omni-directional antenna power. Looking at other evidence about the antenna, the FCC ordered the licensee to show why it should not be ordered to reduce power to bring its signal within that predicted service area – thus protecting a station that had complained of interference from the seemingly directional nature of the KFWR antenna. In response, the KFWR licensee suggested that all purportedly omni-directional antenna patterns have some degree of directionality, especially when side-mounted on a tower. The licensee argued that the FCC had never set standards for how much of such directionality should be allowed – and should not do so by singling out its application, but instead the FCC should look at this on an industry-wide basis. The licensee also offered to remount its antenna to eliminate anything that had been done to “optimize” its signal. The FCC rejected these proposals.

The FCC characterized the licensee’s arguments as claims that “everybody does it” and no one has been caught, so this case should not be pursued either. In response, the FCC said that it recognized that others may have taken advantage of the rules too, but they had a complaint about this case, and they had to do something about it. The FCC found that the licensee had not contested the significant directional nature of its operations – with the ratio of signal from the station in its maximum direction to that in its minimum direction exceeding even the FCC’s rules for maximum to minimum signal ratio for directional antennas. Finding that the station was in fact employing an antenna that had intentionally been designed to produce a directional radiation effect, the FCC ordered it to reduce power to a level that would protect the station that had complained, in accordance with the rules for directional antenna operations.

So what does this case ultimately mean? As we said before, it seems to mean that the FCC will look at cases for those who push the envelope – especially if faced with a complaint. So if you are planning a new FM nondirectional antenna installation with any degree of “optimization,” talk long and hard with your engineer and attorney about this decision to avoid an investment that leads to a problem.