Transmitters capable of sending data over 1km typically require an output power of about one watt and a suitable data input. However, operating such transmitters without a license is illegal in most countries, leading to significant penalties. For those in remote areas, VHF is recommended to stay within line of sight. Certain frequencies, like Citizens Band (27 MHz) and Wireless networking frequencies (2400 MHz), may not require a license in some regions, but users must avoid interference and adhere to power limitations. Consulting local Radio Frequency authorities is advised to explore legal options for long-distance data transmission.