Reply to post: Antenna gain

Samsung says micro-sats could blanket the world with Internet

Paul Crawford Silver badge

Antenna gain

You don't get anything for free, if you have a given power flux density at the Earth (you know, a fixed transmitter power and coverage area) then going up in frequency achieves nothing - the increase in directivity gain for a fixed effective aperture is NOT producing an increase in power, and going to a smaller antenna for a fixed 'gain' is not helping - in fact it is counter-productive. The reason why "free space loss" in link budgets includes wavelength instead of simply being inverse-square is specifically to reconcile the relationship between an antenna's effective area and directivity gain.

The only benefit you get in that scenario from higher frequency use is the directivity gain allows you to separate sources (.e.g. satellites) that are close together. But you pay for it by having to steer the beam very accurately (mechanical or phased array). Also rain losses are massive at W-band so for some users in some areas they won't be seeing better then 95%-ish connectivity.

It makes some sense for users in really sparse areas, but not for high density cities, etc, where putting in some fibre and a few mobile base stations operating at frequencies that penetrate building is going to work much better. The real question (beyond pollution of space when those reach end of life and can't be de-orbited from 2000km altitude for millennia) is the economics of doing so for a large number of very poor users. Yes, I feel they should benefit, but I do wonder if the companies behind this can make money. Iridium went bust because the advent GSM, etc, stole its most profitable user base in the big cities and densely populated areas of wealthy countries.

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