I've seen the different conversions for mW, mV, mV/m, dBm, mostly based on 50 ohms. What I'm interested in is converting a given field strength mV/m, at a given distance for a particular frequency, to the equivalent (decayed) baseline wattage. For instance, in section 73.318, the FCC defines the FM blanket overload boundary as 562 mV/m (115 dBu), having a distance equalling .394 * KW^.5 (ERP), where (I believe) ".394" is supposed to be
50000^.5/562. So, assuming flat terrain with "raw reception" (meaning no antenna and line gain/loss), what would the equivalent ERP wattage be (i.e., if you took a field strength meter and held it next to a transmitter, what would the wattage be to produce 562 mV/m?)? Since wattge can be found from mV/m, what would the equation for decayed wattage (mW_d) be, given an ERP (KW_erp), frequency (MHz) and distance (Km)? Instead of 50, should 2*Pi*60 Hz (~=~ 377) be used for ohms?~Kaimbridge~
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