Total posts : 45366
At my FM frequency my 1/4 wave antenna is only 28″ long. 10 x 28″ = 280″/12 = 23.3333 feet. 1 wavelength at my frequency would be around 9 3/4 feet. So according to your info, the FCC would want to take their reading at 10 times the antenna length. That would be at 23.3333 feet,in my case. With the sensitivity the FCC meters must have, I see no problem with them getting a fairly accurate reading at that distance. They wouldn’t be looking for 250uv/m at that distance tho…probably more like 100um/v. Upon reading that, they would figure the 3 meter field strength to be around 250uv/m, since field strength is inversely proportional to the distance from the antenna.
This is for FM. I don’t know what the proceedure is for AM….this whole thread has been about Pt. 15 FM. Maybe the answer you seek would be on an AM thread?