this post was submitted on 17 Jan 2025
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[–] Corkyskog@sh.itjust.works 26 points 4 days ago (4 children)

Do you need a license to buy a receiver to listen in?

[–] captain_aggravated@sh.itjust.works 10 points 2 days ago* (last edited 2 days ago)

No, only the British are dumb enough to require a license for a receiver.

You can go buy whatever radio you want and listen to hams tell each other where they're from and lie about how well they're hearing each other. Which is most of what they do on shortwave. 1. Ham radio is a game to most of them, the game is "exchange callsigns with people from as many places as you can." 2. There is a law (CFR 97.113(5)) that prohibits "Communications, on a regular basis, which could reasonably be furnished alternatively through other radio services." I read that as it's illegal to have a weekly Wednesday at 5 PM EDT chat with your buddy in Tuscon on 20 meters because the cell phone network can also accomplish that. So are scheduled ragchew nets legal?

If you're going to play around with an HF receiver, ignore the hams and listen out for numbers stations, they're way fucking cooler than us licensed radio dorks.

Don't transmit without a license. If we can hear you, we can find you. Radio isn't like the internet, radio travels in straight (ish) lines. You're literally shining a light into the sky, we can tell where it's coming from. Hams won't do anything to you. No, that's what the FCC is for.

[–] circuitfarmer@lemmy.sdf.org 27 points 4 days ago (1 children)

You do not need a license to listen to ham radio with a traditional transceiver. You only need a license to transmit.

There are no licensing requirements for equipment purchases.

[–] mesamunefire@lemmy.world 18 points 4 days ago (1 children)

Nope that's what the web interface is for.

But an rtlsdr is pretty cheap if you want to go that route. I do satellite tracking with satnogs and it's fun.

[–] Corkyskog@sh.itjust.works 3 points 4 days ago (2 children)

I think I am technologically ignorant when it comes to radio so... I still have questions.

How does the web interface collect the transmissions? Are all the transmissions made digitally accessible with the interface? Why (other than cost) would I want to use a web interface rather than a traditional receiver?

How does the web interface collect the transmissions?

The person or organization hosting the website has an antenna somewhere attached to a Software Defined Radio, or SDR. I honestly don't know how these work at the silicon level, but radio antenna feed line goes in one side, some JFM happens, and USB and/or PCIe computer data comes out the other end. Instead of tuning into such and such frequency with such and such modulation, it sends the raw RF data to the computer to let it process it digitally, with algorithms and GFLOPS and RAM and shit.

Which means, you get to tell it "process the data as if you're a single-sideband radio listening on 14.070MHz Upper Sideband" and you can listen into amateur radio slow scan television. It's basically like you get to remote control someone else's radio receiver.

Are all the transmissions made digitally accessible with the interface?

No. See the above "A person has an antenna somewhere." You can hear what that antenna hears. This will be limited to line of sight for VHF and up, and even HF will be limited by propagation conditions and the nature of the antenna. The hardware they've hooked to their computer may also have its own limitations. Also, their antenna is imperfect because there is no such thing. This is the world's shittiest Wi-Fi antenna (only partially because it fell over).

Why (other than cost) would I want to use a web interface rather than a traditional receiver?

Not all radio transmissions can be heard from everywhere. I can't hear anything above 12 meters out of eastern Europe from here, not in the worst solar cycle since humans learned the sun has cycles. I can hear it loud and clear from some Frenchman who put his SDR online.

[–] cmnybo@discuss.tchncs.de 7 points 4 days ago (1 children)

The web interfaces use SDRs. They can listen to an entire band at one time rather than just a single station.

You will only be able to listen to transmissions that are within range of a web SDR. They work great for HF since that propagates a long ways when the band is open. For VHF and up, you will likely need a local receiver unless there happens to be a web SDR near you that covers the band you want to listen to.

The web SDRs may have better antennas than you do and they are probably in a place with much less RFI than you. You can use them to listen to far away places.