Technically, you’re not allowed to “operate” on bands you’re not licensed for, including rx, but enforcement is difficult, of course.
Edit: If your device has any transmit ability, it falls under above. If your device ONLY has rx capability, it does not. Many of the USB SDR dongles DO have the capability to tx, albeit at only ~0.5 watts. This is generally not advertised in the device, but their chip does technically hav an amplifier capable of sending out signals, though usually you would also need an antenna with a shunt. I'm quite certain on this.
This is incorrect at least in the US. You are allowed to receive practically everything. There's only really a carve out for analog cellphone frequencies, but that's about it.
You just jogged a weird memory out of my head. In the early days of the internet there were sites that had pirate audio streams from analog cell phones. It was pretty sporadic but a very interesting sort of slice of life thing.
> It's a strange thing to see white-snow-static redigitized and then drop bit-rates.
Old-school white snow static is theoretically the most uncompressable thing, right? So some poor encoder is being told to "send this at 384kb!" and it just throws its little robot hands up and says, "fine, here's your super blocky bullshit. I'm going on break..."
Modern codecs detect noise, filter it out and add back artifical noise at the decoder (especially audio codecs can do this with all kinds of noise). I think back in the day, video compression would likely not have an issue as noise is high frequency and if you're compressing images, that's the first thing to go, you'd just get a blurrier image.
That’s under federal law. A few states add some restrictions. 5 of them disallow listening to police frequencies on portable radios without a license (but a ham license is acceptable). Florida and New York are the biggest states with this restriction.
My understanding is that operating on a frequency requires that you be transmitting on it, not whether the device is capable of transmitting on it.
For instance, you can own one of those cheap handheld Baofeng radios that is capable of transmitting on all sorts of frequencies, so long as you never transmit (and you don't listen to any forbidden frequencies)
Happy to be corrected, but all the resources I've dug up say that it doesn't matter whether the device is capable of transmitting or not.
In the us you're allowed to receive everything but the cellular phone spectrum without a license. You or the device needs to be licensed to transmit, however.
Note that this isn't the case everywhere. I believe in the uk it's illegal to listen to air traffic, but I would need to look up the specifics to give anymore detail.
Receiving of certain bands is prohibited, from memory the ones used on cordless phones and something else. All devices sold, say frequency analyzers, have to have a bandgap for them to pass FCC validation. It is common to remove these bandgaps and ignore the law because everyone seems to accept they are really dumb and they wreck the sensitivity of the instrument.
The bandstop filter requirement is mostly a stopgap measure from an analog era when cell phones were basically trunked FM radio systems. That limitation serves no purpose nowadays.
Certainly untrue in the United States, though there are some bands that are prohibited to listen to — the old 800 MHz analog cell phone bands. And you won’t get 500mw transmit out of usb SDR dongles.
Edit: If your device has any transmit ability, it falls under above. If your device ONLY has rx capability, it does not. Many of the USB SDR dongles DO have the capability to tx, albeit at only ~0.5 watts. This is generally not advertised in the device, but their chip does technically hav an amplifier capable of sending out signals, though usually you would also need an antenna with a shunt. I'm quite certain on this.
Again, in real life, it does not matter.