A hotspot is a tiny personal digital-voice station: a radio modem with a small computer, connected to your home internet. Your digital handheld talks to it at very low power, and it carries the audio to an internet-based network. It is your own private link to that network, with or without a repeater nearby.
How a call travels
Radio links (teal) are short and low power. The long distance is carried by the internet (grey).
Your handheld, set to a digital voice mode, sends voice as digital data to the hotspot.
The hotspot receives it, wraps it in internet packets and sends it over your home network.
Network servers route it to the right place: a talkgroup, reflector or room that you chose.
A remote repeater or another hotspot transmits it, and the other station hears you.
Only the two ends are radio. The long distance is the internet, so latency and outages matter. A network is not a substitute for radio in an emergency; see Principles of emergency communication.
Hotspot or repeater?
Hotspot
Repeater
Owner
You
A club or group
Coverage
A house or yard
A wide area
Power
Milliwatts
Watts
Good for
Reaching the network from home
Everyone in the area, including mobile use
Other gateways
A gateway is any station that connects a radio network to another network. The hotspot is the personal version.
A gateway is a station that connects radio to the internet.
Others include EchoLink and similar nodes (voice linked over the internet), APRS gateways that put position and message packets on the internet, and Winlink gateways for email by radio; see EchoLink, IRLP and AllStar, APRS and Winlink and radio email.
In practice
You are the control operator of your hotspot, and its transmissions carry your call sign, so the rules still apply. Pick a frequency that will not interfere with local repeaters or other users.
Each digital voice family (DMR, D-STAR, Yaesu System Fusion) has its own registration, networks and radio settings, so a radio and a hotspot must be set for the same one.
Keep it away from the radio you use to talk to it, and keep its power low. Overloading your own receiver is a common first problem.