A (dB) = 46 + ([DELTA]f2 /1.44)
A(dB) = 47 + 11.5 ([DELTA]f-0.5)
Attenuation in dB = -11.5([Delta]f + 3.6);
Where:
[Delta] f = frequency difference in MHz from the edge of the channel.
A(dB) = Aalternate + 10 log (BWalternate / 500)
where A(dB) is the measured or calculated attenuation value for the reference 500 kHz bandwidth, and Aalternate is the measured or calculated attenuation for a bandwidth BWalternate. Emissions include sidebands, spurious emissions and radio harmonics. Attenuation is to be measured at the output terminals of the transmitter (including any filters that may be employed). In the event of interference caused to any service by out-of-channel emissions, greater attenuation may be required.
47 C.F.R. §74.794