Brian Kirby wrote: > 20 log(base10) (diameter in meters) + 20log(frequency in ghz) +17.8 = dbi > That assumes some nominal efficiency? I'll have to remember that one.. 17.8 It's like the 32.44 dB for free space loss between isotropes 1 km apart at 1 MHz (+20log10(dist in km) + 20log10(freq in MHz))