vhf/uhf

[landonjensen]

what is the difference between vhf and uhf?

 

[UPMan]

The frequency (or wavelength) of the modulating carrier.

VHF Very High Frequency 30 MHz - 300 MHz 10 m - 1 m
UHF Ultra High Frequency 300 MHz - 3 GHz 1 m - 10 cm

(see http://wiki.radioreference.com/index.php/spectrum)

 

[BoxAlarm187]

They're two different frequency ranges. In the widest aspect, VHF is 30-300MHz and UHF is 300-3000MHz. However, that's awfully broad, so here's a further breakdown:

The general services in the VHF band are:

• 30–46 MHz: Licensed 2-way land mobile communication
• 30–88 MHz: Military VHF-FM, including SINCGARS
• 43–50 MHz: Cordless telephones, "49 MHz" FM walkie-talkies, and mixed 2-way mobile communication
• 50–54 MHz: Amateur radio 6 meter band
• 54–72 MHz: TV channels 2-4 (to be auctioned for other uses once conversion to digital TV has been accomplished)
• 72–75.5 MHz: Remote Control devices
• 75.5–87.5 MHz: TV channels 5-6 (to be auctioned for other uses once conversion to digital TV has been accomplished)
• 87.5–108 MHz: FM radio broadcasting (88–92 non-commercial, 92–108 commercial)
• 108–118 MHz: Air navigation beacons VOR
• 118–132 MHz: Airband for Air Traffic Control, AM, 121.5 MHz is emergency frequency
• 132–144 MHz: Auxiliary civil services, satellite, space research, and other miscellaneous services
• 144–148 MHz: Amateur band 2 Meters
• 148–174 MHz: "VHF Business band," the unlicensed Multi-Use Radio Service (MURS), and other 2-way land mobile, FM
• 156–174 MHz VHF Marine Radio; narrow band FM, 156.8 MHz (Channel 16) is the maritime emergency and contact frequency
• 162.40–162.55: NOAA Weather Stations, narrowband FM
• 174–216 MHz: TV channels 7 through 13, and professional wireless microphones (low power, certain exact frequencies only)
• 216–222 MHz: mixed services
• 222–225 MHz: Amateur "1¼ Meter" band (really closer to 1.33M)
• above 225 MHz: Federal services, notably military aircraft radio (225–400 MHz) AM, including HAVE QUICK, dGPS RTCM-104

A brief summary of some UHF frequency usage:

• 300–420 MHz: government use, including meteorology
• 420–450 MHz: radiolocation and Amateur radio (ham - 70 cm band)
• 450–470 MHz: UHF business band, GMRS, and FRS 2-way "walkie-talkies"
• 470–512 MHz: TV channels 14–20, public safety
• 512–698 MHz: TV channels 21–51 (channel 34 used for radar, channel 37 used for radio astronomy)
• 698–806 MHz: TV channels 52–69 (to be auctioned for other uses once conversion to digital TV has been accomplished)
• 806–824 MHz: pocket pagers and Nextel SMR band (formerly TV channels 70–72)
• 824–849 MHz: Cellular phones, A & B franchises, mobile phone (formerly TV channels 73–77)
• 849–869 MHz: public safety 2-way (fire, police, ambulance - formerly TV channels 77–80)
• 869–894 MHz: cellular phones, A & B franchises, base station (formerly TV channels 80–83)
• 902–928 MHz: ISM band: cordless phones and stereo, RFID, datalinks, Amateur radio (33 cm band)
• 928–960 MHz: mixed Studio-Transmitter Links, mobile 2-way, other
• 1240–1300 MHz: Amateur radio (ham - 23 cm band)
• 1850–1910 MHz: PCS mobile phone—note below
• 1930–1990 MHz: PCS base stations—note below
• note: order is A, D, B, E, F, C blocks. A, B, C = 15 MHz; D, E, F = 5 MHz
• 2310–2360 MHz: Satellite radio (Sirius and XM)
• 2390–2450 MHz: Amateur radio (ham - 13 cm band)
• 2400–2483.5 MHz: ISM, IEEE 802.11, 802.11b, 802.11g Wireless LAN
• around 2450 MHz: Microwave oven

Giving credit where credit is due: above information gleaned from Wikipedia.

 

[kingpin]

And from an end user perspective, you'll find VHF radios used in more rural open areas where as UHF usage is used in more in urban areas due to it's better penetration in buildings due to it's wavelength being much smaller.