Yes, radar detectors are generally legal in the United States. This is because detectors are intended for drivers to be mindful of their driving speeds. Additionally, radar detectors are prohibited in all commercial vehicles and all vehicles 18,000 pounds or heavier.

The 5.9 GHz band, known as the Dedicated Short Range Communications Service (DSRCS), is intended to promote automobile safety….Public Safety Spectrum.

The frequencies are 121.5 MHz for civilian, also known as International Air Distress (IAD) or VHF Guard, and 243.0 MHz for military use, also known as Military Air Distress (MAD) or UHF Guard.

20 meters – 14.0–14.35 MHz – Considered the most popular DX band; usually most popular during daytime. QRP operators recognize 14.060 MHz as their primary calling frequency in that band. Users of the PSK31 data mode tend to congregate around 14.070 MHz. Analog SSTV activity centers on 14.230 MHz.

wireless alarm systems
The high band (868–870 MHz) is primarily used by wireless alarm systems, including fire, intruder and social alarms which are each subject to different operational and technical requirements.

600 MHz
Prohibition on use of the 700 MHz band In 2010, the FCC prohibited the use of wireless mics and devices on unused broadcast channels on the 600 MHz service band and on the 700 MHz band – specifically the frequencies between 698 and 806 MHz.

The Mars Relay uses frequencies of 437.1 MHz for transmission, and 401.5 and 405.6 MHz for reception. Because these frequencies are near the radio amateur bands, Hams will have the opportunity to help out NASA and listen for the Mars Relay beacon transmission at 437.1 MHz.

For ham radio operators, you’ll use the frequency range from 420 – 450MHz. Unlike the reliability of VHF radio waves, UHF has a much shorter wavelength and is prone to interference from basically any solid object, whether that’s a building blocking your signal or even your body.

Those devices do not have Part 95 equipment certification, so they are not authorized for use in FRS or GMRS, i.e. they are not “capable of operating under his subpart.” [sic] They can be used by amateurs, but only on amateur frequencies.

433MHz frequency band has been widely used in almost many control applications, while 868MHz is exclusively reserved for communication between wireless sensor networks. 868MHz band is exclusively opened for wireless alarm system, it’s less likely to be interfered.

800 m
The advantages of the 868 MHz radio transmission. The ISM band frequencies enable to have a compact radio bridge with a high range: In free space and with a ¼ wavelength antenna (i.e. only 8,6cm), the range is up to 800 m. Radiofrequencies can go through out concrete walls.

80 Meters consists of the frequencies from 3.5–4.0 MHz (3500–4000 kHz). The band is best worked at night during the winter. The FCC has granted hams secondary access on USB only to five discrete 2.8-kHz-wide channels.

170.5750 MHz – Forest Firefighting and Conservation [ 90.265] 171.0250 MHz – hydrological or meteorological data, fixed [ 90.265] 171.0375 MHz – hydrological or meteorological data, fixed [ 90.265] 171.0450 MHz – Wireless microphones [ 90.265] 171.0500 MHz – hydrological or meteorological data, fixed [ 90.265]

For each band, only those license classes with privileges on that band are listed. Technician licensees have limited privileges below 30 MHz. At all times, transmitter power must be the minimum necessary to carry out the desired communications.

The HF bands are where you are going to find most of your DX or long-distance stations. These frequencies span from 3.5 MH (80 meters) to 29.7 MHz (10 meters). 80 Meters 80 Meters consists of the frequencies from 3.5–4.0 MHz (3500–4000 kHz).