/diy/ - Do It Yourself

>>1809062

a receiver is a two-stages machine: first, they collect the RF, then they convert it to the "mode" being used (generally audio). There may be a third stage for a supplementary conversion (say, packet radio)

now, traditional radios have both stages implemented in hardware.
SDR's have the second stage done by software.

Thus an SDR is simpler than a traditional radio in that it doesn't have a hardware 2nd stage; it just ships RF data to some computer, and the computer does the magic.

that means an SDR could ship large chunks of data (say, a wider chunk of the RF spectrum, possibly 50 MHz) letting the computer to decode multiple different channels and modes at once.

You may even have an HT doing it "the SDR way": a receiver collects the data, a small board computer decodes it the way the user expects ("an audio channel at X.YZ mhz FM").

Never forget the first RTL-SDR was sold as a TV receiver. Someone took the time to disassemble the software and found out it just decoded TV data off RF data.

So, an SDR can do literally any mode, existing or yet-to-be-invented, as long as there's enough computing power and enough hardware sampling. If your SDR can collect 1 MHz worth of RF, the software will be able to do any mode requiring 1 MHz or less. Say, you could broadcast TV over the HF using an 8 MHz wide channel