The recently-passed FAA Reauthorization Act (H.R. 636) requires the Federal Aviation Administration within one year to issue regulations requiring marking of certain towers to
The law does not specifically exempt amateur radio but its provisions suggest that very few ham towers would be affected. Under the law, a "covered tower" must be self-supporting or guyed, be less than 10 feet in diameter at the base, be between 50 and 200 feet tall and have "accessory facilities" on which antennas or other specified instruments are mounted. In addition, it must be located outside of an incorporated city or town, on farmland or "undeveloped" land where low-flying aircraft routinely operate. Towers that are adjacent to buildings or within the area of a farm occupied by buildings are exempted. As such, the vast majority of amateur towers would not be subject to this new law.
The ARRL says it will monitor the FAA's follow-up on the new requirements and will comment as part of the normal FAA rulemaking process (which is similar to the FCC's).