Radio World recently posted a brief item about three notices of unlicensed operation to three different persons that the FCC issued in Portland, OR to what is apparently the same station operating on the AM dial. There are a good dozen notices issued every month, and not every one gets reported on by RW. Apparently this one was notable because it was on the AM band and because the broadcasters allegedly were using 1710 khz, which is up in the so-called “expanded band.” Most unlicensed broadcasters use the FM band for which it’s easier to obtain transmitters and antennas.
However, pirates on the AM band are not that unusual, although the FCC sniffs out far fewer of them. In fact, the Commission’s Enforcement Bureau issued four additional notices to unlicensed AM broadcasters in Omaha, NE, Sublimity, OR, Brockton, MA and Malden, MA (though the FCC detected the Malden signal in November, 2009). Interestingly, the notice in Sublimity was actually issued to the City of Sublimity which the FCC says was operating from a water tower at comparatively high power.
What’s more interesting about this particular station is that the FCC claims the water tower functioned as part of the antenna system. According to the FCC’s Part 15 rules it’s permissible to have an unlicensed AM station that transmits with 100 milliwatts of power as long as “”the total length of the transmission line, antenna, and
ground lead (if used) shall not exceed approximately 3 meters.” However at the Sublimity station
the agent observed that the approximate length of the vertical whip antenna and the ground lead used by the station was 3 meters, however, the referenced antenna was attached to an unshielded radiating metal water reservoir tower and the height of the metal water reservoir tower measured approximately 100 feet (31.2 meters).
Due to AM’s long wavelengths, longer antennas increase your transmitting efficiency. Using a big metal water tower is clever, provided you don’t get caught.
Just for fun, here’s a short YouTube recording of a Grosse Point, MI AM pirate as received on an antique radio: