Total posts : 45366
is good, but to echo Neil’s comment in reply 2 above, the maximum field from this directional antenna still could not exceed 250 µV/m at the peak of its main lobe.
Its free space gain at 98 MHz is shown as 8 dB above a (1/2-wave) dipole. So the matched input power it would need to produce the maximum field is only ~40% of what a dipole would need. That value would be 0.4 x 0.000 000 0114 watts = 4.56 nanowatts.
Probably not many “Part 15” FM transmitters can be accurately adjusted for either of these output powers.