With the right accessories for it including its calibrated antenna(s),
and deep pockets, the Z-Technology R-507 Portable Field Strength
Meter will get you from 0.3 MHz to 1 GHz with +/- 2 dB accuracy
traceable to NIST.
The calibrated antennas allow a direct readout in units of dBmW,
dBµV, or dBµV/m.
http://www.ztechnology.com/
RF