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One way to easily judge if an FM station is, indeed, a “powerhouse” is to remember that a field strength of 1 V/m at 1 km corresponds to slightly over 20 kW of radiated power from a half wave dipole. This applies to any combination of field strengths and distances where the product of the field strength and distance equals 1 (for example, 2 V/m at .5 km, and 4 V/m at .25 km). 1 V/m = 1,000,000 uV/m, and 1 km = 1000 m. Doing the math on the enforcement action that started this thread, the product is much smaller than 1, accounting for the unexpectedly low radiated power calculated by Rich.
Here is a recent enforcement action for a real powerhouse:
Two field strength readings, separated by three months, are mentioned in this NOUO. One reading corresponds to 488 kW, and the other to 174 kW. These results suggest that calculating radiated power from field strength readings is not an exact science. The calculated power appears to be unrealistically high, and the two readings on the same station vary from each other greatly. Of course, the station power could have been changed in three months.
This particular NOUO was issued to the owner of the building where the station was located. The owner lives in Boca Raton, FL, which is a nice area, but the building is in Lauderdale Lakes, which is a not-so-nice area. Perhaps the owner is not involved with the pirate station, and he is merely a landlord with a bad tennant. If this is the case, the owner has been put in the difficult position of being required to stop an illegal activity on his property. It’s too bad that NOUOs contain so little information. If this case ever gets to the NAL level, we will learn more, because NALs have a lot more details.
There have been several such powerhouse stations in the Ft. Lauderdale area recently. I was not able to find anything published by the news media about these cases.