Legally speaking, no matter how small the power is, you have to apply, unless you use a civilian walkie-talkie. This does not need to be filed, but the power is very small, and the regulation cannot exceed 0.5W, only a dozen or twenty channels.

First, you have to pass the operation license exam, and then get the call sign (these two items are equivalent to driver's license and car number plate). After the establishment of radio stations, you must apply for a radio license for each station (this is equivalent to a car driving license).

HF band can communicate all over the world, and it is estimated that it is often monitored. Besides, people will ignore you if you don't call.

VHF is mainly used for amateurs in 50MHz band (6m band) and150mHz band (2m band). It is estimated that household use will not be caught, and it will not occupy other people's frequency bands, but driving without a license is undoubtedly illegal.

UHF is a commonly used interphone frequency band (400MHz-470MHz), and it is estimated to be the most popular frequency band. In this frequency band, the power of the hand station is generally less than 5W, and the station can achieve 50W ~ 100W. Try not to turn on high power, and don't temporarily use other people's bands. Because people will report you, your communication content will be heard by more people, which is not conducive to privacy. ...

If you need to use 2.4GHz and 5GHz bands for communication, it may be better, because these high-frequency bands are transmitted within the line of sight and generally do not interfere with others.