How does a ham Internet gateway work?
Someone, or often an amateur radio club, installs a radio at a site with internet access. From there, they upload the received signals to a network of servers on the internet, or host the server themselves.
There are many such services. Here are a few, and by no means exhaustive:
- WebSDR (predominantly independent HF receivers)
- Brandmeister (mostly linked DMR repeaters, anyone can listen via internet)
- DMR-MARC (also DMR repeaters, but this one less open than Brandmeister. No internet listening capability, but no license is required to listen on a DMR radio in the US)
- EchoLink (Used to link FM repeaters, also runs as Windows software)
- P25NX (a similar thing to Brandmeister and DMR-MARC, but for P25)
- D-STAR reflectors (similar to DMR except much less mature. You can probably find a place to listen online that isn't broken if you try hard)
Wouldn't the Internet gateway need to be setup for the same frequency I'm transmitting on
and in the same area,
Well, the receiver has to be in range at least. The effective range of your transmission will depend on the frequency, power, antenna, terrain, and other factors; and could be anywhere from global to less than a mile.
again, no guarantee and highly unlikely?
I wouldn't say it's highly unlikely. Nearly all digital repeaters, and most analog FM repeaters, are on some kind of linking system. And HF has such a long range, it's quite likely there's a receiver in range somewhere.
Ie, if I'm going to be broadcasting in California and I would like someone in New York, Peru, Greenland, etc., is it possible for them to listen?
Assuming they have internet access, and aren't in some jurisdiction that heavily censors the internet, then yes.
More problematic though is you can't legally broadcast in California, or any other part of the US:
§97.113 Prohibited transmissions.
(b) An amateur station shall not engage in any form of broadcasting, nor may an amateur station transmit one-way communications except as specifically provided in these rules; nor shall an amateur station engage in any activity related to program production or news gathering for broadcasting purposes, except that communications directly related to the immediate safety of human life or the protection of property may be provided by amateur stations to broadcasters for dissemination to the public where no other means of communication is reasonably available before or at the time of the event.
Would it also be available in real-time or close to real-time or would there be a substantial delay.
Delay won't be more than a couple seconds, probably less.