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Comment by cconcepts | Hacker News Reader

This is quite impressive: does anyone know what resolution images can be captured like this?

I'm assuming this is perfectly legal?

The downlink is analog (thus the calibration scales in the margins), and with this kind of hardware your image quality is limited by analog signal quality effects. At the source, though, APT ([false]-color pictures from NOAA satellites, as opposed to weatherfax charts) is 980px wide.

The satellites are a public service and privately owned receivers are nothing new, the RTL-SDR just made it a whole lot cheaper. The first time I saw this done at an amateur radio meet, the hardware cost many thousands of dollars and occupied a card table. The RTL-SDR is a bit magical in what it's done for hobbyist receiving.

Absolutely legal. Resolution depends on the satellite (system). It's digital data, so the resolution does not depend on your hardware.

I thought the easiest signals to pick up from weather sats are actually analog - https://en.wikipedia.org/wiki/Automatic_Picture_Transmission

It seems theres at least a Russian weather sat, which you can pick up which is transmitting digital data - http://www.rtl-sdr.com/rtl-sdr-tutorial-receiving-meteor-m-n...

Ah sorry, I meant the kind of data, not the transmission method. No idea if this even makes sense. I meant that you get a image of pixels from them, the resolution does not depend on your receiver. The image pixel quality itself ("color") will be subject to analog effects though. Not a scientist, just a hobbyist with "dangerous semi-wisdom" typing this. ;)

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