3 ms·

I agree. In radio the size of the aperture across which the currents flow is inversely proportional to the size of the antenna main beam. The pattern is literal

I agree. In radio the size of the aperture across which the currents flow is inversely proportional to the size of the antenna main beam. The pattern is literally the fourier transform of the currents. The bigger the smaller. There's no getting around needing to have a giant antenna surface (or array). In order to have the required extremely tiny main beams (high gain), to not instantly lose most of the power to spreading losses, LEO beamed power at reasonable microwave frequencies requires ~5km wide aperture. We cannot build 5 km things in space yet. It is not really something worth discussing till we're doing that regularly. Space based power isn't that much more available than ground based so there's not much value added to the huge increase in cost orbit requires.

avmich 4y ago
Henry Spencer (https://en.wikipedia.org/wiki/Henry_Spencer https://en.wikipedia.org/wiki/Henry_Spencer) a couple of months ago run a presentation of current state in space power. Land antennas (rectennas) were in this size, ~5km diameter, made mostly from chicken wire. Cheap, and you can still grow vegetables or anything under it. Not much risk walking under it either. Space antennas are an order of magnitude smaller, ~250 meters (for gigawatt-class power stations). To me, this all seem to need a lot of data and some careful calculations :) .
fnordpiglet 4y ago
They discuss they would build a 3.5 mile array using unfolding tiles. They seem to appreciate the challenges and are researching how to overcome them. Isn’t this how we turn “cannot” into can ?