The echo power is measured in terms of radar cross-section, , , or  (total power, SC + OC) and is equal to the cross-sectional area of a metallic sphere (perfect reflector) at the same distance as the target that would return the same echo power.
ðɪ ˈɛkoʊ pˈaʊɚɹ ɪz mˈɛʒɚd ɪn tˈɜːmz ʌv ɹˈeɪdɑːɹ kɹˈɔssˈɛkʃən, , , ɔːɹ tˈoʊɾəl pˈaʊɚ, ˌɛssˈiː plˈʌs ˌoʊsˈiː ænd ɪz ˈiːkwəl tə ðə kɹˈɔssˈɛkʃənəl ˈɛɹiə əvə mətˈælɪk sfˈɪɹ pˈɜːfɛkt ɹᵻflˈɛktɚ æt ðə sˈeɪm dˈɪstəns æz ðə tˈɑːɹɡɪt ðæt wʊd ɹᵻtˈɜːn ðə sˈeɪm ˈɛkoʊ pˈaʊɚ.