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lonestarbandit posted:

"or are you saying all of the 11m gain figures are fantasy, from all the beam manufacturers, type irrelevant."

all gain figures for all antennas are irrelevant in the absence of a determination of the radiation efficiency of the antenna in question. until then we can only speak in terms of directivity.

dB. gain = 10 log (power out / power in)

dB. loss = 10 log (power in / power out)

unfortunately, gain cannot even be calculated until the radiation efficiency of the antenna has been determined. until then, directivity is all that can be discussed. the

same could be said in regard to system losses.

gain = radiation efficiency X directivity.

gain and directivity are differentiated. you can have an antenna with 3 dB. of "directivity" (at some angle) but if the radiation efficiency of that antenna is only 50% then "gain" is only 1.5 dB.. directivity does not automatically equal "gain" unless all antennas are assumed to be 100% efficient. i promise you that is not even the case, particularly where commercially manufactured antennas are involved.

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