Question: What does VHF stand for in VHF-band radar?

Ultra high frequency








ITU radio bands
 1 (ELF) 2 (SLF) 3 (ULF) 4 (VLF) 5 (LF) 6 (MF) 7 (HF) 8 (VHF) 9 (UHF) 10 (SHF) 11 (EHF) 12 (THF)
EU/NATO/US ECM radio bands

A
B
C
D
E
F
G
H
I
J
K
L
M
N

IEEE radio bands

HF
VHF
UHF
L
S
C
X
Ku
K
Ka
V
W
mm

Other TV and radio bands

I
II
III
IV
V
VI
vt
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300megahertz (MHz) and 3gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter (one decimeter). Radio waves with frequencies above the UHF band fall into the super-high frequency (SHF) or microwave frequency range. Lower frequency signals fall into the VHF (very high frequency) or lower bands.  UHF radio waves propagate mainly by line of sight; they are blocked by hills and large buildings although the transmission through building walls is strong enough for indoor reception. They are used for television broadcasting, cell phones, satellite communication including GPS, personal radio services including Wi-Fi and Bluetooth, walkie-talkies, cordless phones, and numerous other applications.
The IEEE defines the UHF radar band as frequencies between 300MHz and 1GHz.[1] Two other IEEE radar bands overlap the ITU UHF band: the L band between 1 and 2GHz and the S band between 2 and 4GHz.


Propagation characteristics


Radio waves in the UHF band travel almost entirely by line-of-sight propagation (LOS) and ground reflection; unlike in the HF band there is little to no reflection from the ionosphere (skywave propagation), or ground wave.[2]  UHF radio waves are blocked by hills and cannot travel far beyond the horizon, but can penetrate foliage and buildings for indoor reception.   Since the wavelengths of UHF waves are comparable to the size of buildings, trees, vehicles and other common objects, reflection and diffraction from these objects can cause fading due to multipath propagation, especially in built-up urban areas.   Atmospheric moisture reduces, or attenuates, the strength of UHF signals over long distances, and the attenuation increases with frequency. UHF TV signals are generally more degraded by moisture than lower bands, such as VHF TV signals.
Since UHF transmission is limited by the visual horizon to 30–40miles (48–64km) and often to shorter distances by local terrain, it allows the same frequency channels to be reused by other users in neighboring geographic areas (frequency reuse). Public safety, business communications and personal radio services such as GMRS, PMR446, and UHF CB are often found on UHF frequencies as well as IEEE 802.11 wireless LANs ("Wi-Fi"). The widely adopted GSM and UMTS cellular networks use UHF cellular frequencies.  Radio repeaters are used to retransmit UHF signals when a distance greater than the line of sight is required.
Occasionally when conditions are right, UHF radio waves can travel long distances by tropospheric ducting as the atmosphere warms and cools throughout the day.
Antennas

The length of an antenna is related to the length of the radio waves used.  Due to the short wavelengths, UHF antennas are conveniently stubby and short; at UHF frequencies a quarter-wave monopole, the most common omnidirectional antenna is between 2.5 and 25cm long.  UHF wavelengths are short enough that efficient transmitting antennas are small enough to mount on handheld and mobile devices, so these frequencies are used for two way land mobile radio systems, such as walkie-talkies, two way radios in vehicles, and for portable wireless devices; cordless phones and cell phones. Omnidirectional UHF antennas used on mobile devices are usually short whips, sleeve dipoles, rubber ducky antennas or the planar inverted F antenna (PIFA) used in cellphones.  Higher gain omnidirectional UHF antennas can be made of collinear arrays of dipoles and are used for mobile base stations and cellular base station antennas.
The short wavelengths also allow high gain antennas to be conveniently small.  High gain antennas for point-to-point communication links and UHF television reception are usually Yagi, log periodic, corner reflectors, or reflective array antennas. At the top end of the band slot antennas and parabolic dishes become practical. For satellite communication, helical, and turnstile antennas are used since satellites typically employ circular polarization which is not sensitive to the relative orientation of the transmitting and receiving antennas. For television broadcasting specialized vertical radiators that are mostly modifications of the slot antenna or reflective array antenna are used: the slotted cylinder, zig-zag, and panel antennas.
Applications
UHF television broadcasting fulfilled the demand for additional over-the-air television channels in urban areas.  Today, much of the bandwidth has been reallocated to land mobile, trunked radio and mobile telephone use. UHF channels are still used for digital television.
UHF spectrum is used worldwide for land mobile radio systems for commercial, industrial, public safety, and military purposes. Many personal radio services use frequencies allocated in the UHF band, although exact frequencies in use differ significantly between countries.
Major telecommunications providers have deployed voice and data cellular networks in UHF/VHF range. This allows mobile phones and mobile computing devices to be connected to the public switched telephone network and public Internet.
UHF radars are said to be effective at tracking stealth fighters, if not stealth bombers.[3]
Examples of UHF frequency allocations
Australia
UHF citizens band(Land mobile service): 476–477MHz
Television broadcasting uses UHF channels between 503 and 694MHz
Fixed point-to-point Link 450.4875 - 451.5125  MHz
Land mobile service  457.50625 - 459.9875 MHz
Mobile satellite service: 406.0000 - 406.1000  MHz
Segment and Service examples: Land mobile for private,  Australian, State and Territory Government, Rail industry and Mobile-Satellite [4]
Canada
430–450MHz: Amateur radio (ham – 70cm band)
470–806MHz: Terrestrial television (with select channels in the 700MHz band left vacant)
1452–1492MHz: Digital Audio Broadcasting (L band)[5]
Many other frequency assignments for Canada and Mexico are similar to their US counterparts
United Kingdom
380–399.9MHz: Terrestrial Trunked Radio (TETRA) service for emergency use
430–440MHz: Amateur radio (ham – 70 cm band)
446.0–446.2 MHz: European unlicensed PMR service => PMR446
457–464MHz: Scanning telemetry and telecontrol, assigned mostly to the water, gas, and electricity industries
606–614MHz: Radio microphones and radio-astronomy
470–862MHz: Previously used for analogue TV channels 21–69 (until 2012).
Currently channels 21–35, 37 and 39–60 are used for Freeview digital TV.[6] Channel 36 is used for radar; channel 38 was used for radio astronomy but has been cleared to allow PMSE users access on a licensed, shared basis.
791–862MHz,[7] i.e. channels 61–69 inclusive were previously used for licensed and shared wireless microphones (channel 69 only), has since been allocated to 4G cellular communications.
863 - 865MHz: Used for licence-exempt wireless systems.
863–870MHz: Short range devices, LPWAN IoT devices such as NarrowBand-IoT.
870–960MHz: Cellular communications (GSM900 - Vodafone and O2 only) including GSM-R and future TETRA
1240–1325MHz: Amateur radio (ham – 23cm band)
1710–1880MHz: 2G Cellular communications (GSM1800)
1880–1900MHz: DECT cordless telephone
1900–1980MHz: 3G cellular communications - mobile phone uplink
2110–2170MHz: 3G cellular communications - base station downlink
2310–2450MHz: Amateur radio (ham – 13cm band)
United States
UHF channels are used for digital television broadcasting on both over the air channels and cable television channels. Since 1962, UHF channel tuners (at the time, channels 14-83) have been required in television receivers by the All-Channel Receiver Act. However, because of their more limited range, and because few sets could receive them until older sets were replaced, UHF channels were less desirable to broadcasters than VHF channels (and licenses sold for lower prices).
A complete list of US Television Frequency allocations can be found at North American Television Frequencies.
There is a considerable amount of lawful unlicensed activity (cordless phones, wireless networking) clustered around 900MHz and 2.4GHz, regulated under Title 47 CFR Part 15. These ISM bands – frequencies with a higher unlicensed power permitted for use originally by Industrial, Scientific, Medical apparatus – are now some of the most crowded in the spectrum because they are open to everyone. The 2.45GHz frequency is the standard for use by microwave ovens, adjacent to the frequencies allocated for Bluetooth network devices.
The spectrum from 806MHz to 890MHz (UHF channels 70–83) was taken away from TV broadcast services in 1983, primarily for analog mobile telephony.
In 2009, as part of the transition from analog to digital over-the-air broadcast of television, the spectrum from 698MHz to 806MHz (UHF channels 52–69) was removed from TV broadcasting, making it available for other uses. Channel 55, for instance, was sold to Qualcomm for their MediaFLO service, which was later sold to AT&T, and discontinued in 2011. Some US broadcasters had been offered incentives to vacate this channel early, permitting its immediate mobile use. The FCC's scheduled auction for this newly available spectrum was completed in March 2008.[8]
The FCC has allowed Americans to connect any device and any application to the 22MHz of radio spectrum that people are calling the 700MHz band. The FCC did not include a wholesale condition, which would have required the owner of the band to resell bandwidth to third parties who could then service the end user. Google argued that the wholesale requirement would have stimulated internet competition. As of 2007, 96% of the country's broadband access was controlled by DSL and cable providers. A wholesale condition could have meant a third option for internet service.[9]
225–420MHz: Government use, including meteorology, military aviation, and federal two-way use[10]
420–450MHz: Government radiolocation and amateur radio (70 cm band)
433MHz: Short range consumer devices including automotive, alarm systems, home automation, temperature sensors
450–470MHz: UHF business band, General Mobile Radio Service, and Family Radio Service 2-way "walkie-talkies", public safety
470–512MHz: Low-band TV channels 14–20 (shared with public safety land mobile 2-way radio in 12 major metropolitan areas scheduled to relocate to 700MHz band by 2023[11])
512–608MHz: Medium-band TV channels 21–36
608–614MHz: Channel 37 used for radio astronomy and wireless medical telemetry[12]
614–698MHz: Mobile broadband shared with TV channels 38–51 auctioned in April 2017. TV stations will relocate by 2020.
617–652MHz: Mobile broadband service downlink
652–663MHz: Wireless microphones (higher priority) and unlicensed devices (lower priority)
663–698MHz: Mobile broadband service uplink
698–806MHz: Was auctioned in March 2008; bidders got full use after the transition to digital TV was completed on June 12, 2009 (formerly high-band UHF TV channels 52–69)
806–816MHz: Public safety and commercial 2-way (formerly TV channels 70–72)
817–824MHz: ESMR band for wideband mobile services (mobile phone) (formerly public safety and commercial 2-way)
824–849MHz: Cellular A & B franchises, terminal (mobile phone) (formerly TV channels 73–77)
849–851MHz: Commercial aviation air-ground systems (Gogo)
851–861MHz: Public safety and commercial 2-way (formerly TV channels 77–80)
862–869MHz: ESMR band for wideband mobile services (base station) (formerly public safety and commercial 2-way)
869–894MHz: Cellular A & B franchises, base station (formerly TV channels 80–83)
894–896MHz: Commercial aviation air-ground systems (Gogo)
896–901 MHz: Commercial 2-way radio
901–902 MHz: Narrowband PCS: commercial narrowband mobile services
902–928MHz: ISM band, amateur radio (33 cm band), cordless phones and stereo, radio-frequency identification, datalinks
928–929 MHz: SCADA, alarm monitoring, meter reading systems and other narrowband services for a company internal use
929–930MHz: Pagers
930–931 MHz: Narrowband PCS: commercial narrowband mobile services
931–932MHz: Pagers
932–935 MHz: Fixed microwave services: distribution of video, audio and other data
935–940MHz: Commercial 2-way radio
940–941 MHz: Narrowband PCS: commercial narrowband mobile services
941–960MHz: Mixed studio-transmitter fixed links, SCADA, other.
960–1215MHz: Aeronautical radionavigation
1240–1300MHz: Amateur radio (23 cm band)
1300–1350 MHz: Long range radar systems
1350–1390 MHz: Military air traffic control and mobile telemetry systems at test ranges
1390–1395 MHz: Proposed wireless medical telemetry service. TerreStar failed to provide service by the required deadline[13].
1395–1400 MHz: Wireless medical telemetry service
1400–1427 MHz: Earth exploration, radio astronomy, and space research
1427–1432 MHz: Wireless medical telemetry service
1432–1435 MHz: Proposed wireless medical telemetry service. TerreStar failed to provide service by the required deadline[13].
1435–1525MHz: Military use mostly for aeronautical mobile telemetry (therefore not available for Digital Audio Broadcasting, unlike Canada/Europe)
1525–1559MHz: Skyterra downlink (Ligado is seeking FCC permission for terrestrial use[14])
1526–1536 MHz: proposed Ligado downlink
1936–1559 MHz: proposed guard band
1559–1610MHz: Radio Navigation Satellite Services (RNSS) Upper L-band
1563–1587MHz: GPS L1 band
1593–1610MHz: GLONASS G1 band
1559–1591MHz: Galileo E1 band (overlapping with GPS L1[15])
1610–1660.5MHz: Mobile Satellite Service
1610–1618: Globalstar uplink
1618–1626.5MHz: Iridium uplink and downlink[14]
1626.5–1660.5MHz: Skyterra uplink (Ligado is seeking FCC permission for terrestrial use[14])
1627.5–1637.5 MHz: proposed Ligado uplink 1
1646.5–1656.5 MHz: proposed Ligado uplink 2
1660.5–1668.4 MHz: Radio astronomy observations. Transmitting is not permitted.
1668.4–1670 MHz: Radio astronomy observations. Weather balloons may utilize the spectrum after an advance notice.
1670–1675MHz: Geostationary Operational Environmental Satellite transmissions to three earth stations in Wallops Island, VA; Greenbelt, MD and Fairbanks, AK. Nationwide broadband service license in this range is held by a subsidiary of Crown Castle International Corp. who is trying to provide service in cooperation with Ligado Networks.[16]
1675–1695MHz: Meteorological federal users
1695–1780MHz: AWS mobile phone uplink (UL) operating band
1695–1755MHz: AWS-3 blocks A1 and B1
1710–1755MHz: AWS-1 blocks A, B, C, D, E, F
1755–1780MHz: AWS-3 blocks G, H, I, J (various federal agencies transitioning by 2025[17])
1780–1850MHz: exclusive federal use (Air Force satellite communications, Army's cellular-like communication system, other agencies)
1850–1920MHz: PCS mobile phone—order is A, D, B, E, F, C, G, H blocks. A, B, C = 15MHz; D, E, F, G, H = 5MHz
1920–1930MHz: DECT cordless telephone
1930–2000MHz: PCS base stations—order is A, D, B, E, F, C, G, H blocks. A, B, C = 15MHz; D, E, F, G, H = 5MHz
2000–2020MHz: lower AWS-4 downlink (mobile broadband)
2020–2110MHz: Cable Antenna Relay service, Local Television Transmission service, TV Broadcast Auxiliary service, Earth Exploration Satellite service
2110–2200MHz: AWS mobile broadband downlink
2110–2155MHz: AWS-1 blocks A, B, C, D, E, F
2155–2180MHz: AWS-3 blocks G, H, I, J
2180–2200MHz: upper AWS-4
2200–2290 MHz: NASA satellite tracking, telemetry and control (space-to-Earth, space-to-space)
2290–2300MHz: NASA Deep Space Network
2300–2305MHz: Amateur radio (13 cm band, lower segment)
2305–2315MHz: WCS mobile broadband service uplink blocks A and B
2315–2320MHz: WCS block C (AT&T is pursuing smart grid deployment[18])
2320–2345MHz: Satellite radio (Sirius and XM)
2345–2350MHz: WCS block D (AT&T is pursuing smart grid deployment[18])
2350–2360MHz: WCS mobile broadband service downlink blocks A and B
2360–2390MHz: Aircraft landing and safety systems
2390–2395MHz: Aircraft landing and safety systems (secondary deployment in a dozen of airports), amateur radio otherwise
2395–2400MHz: Amateur radio (13 cm band, upper segment)
2400–2483.5MHz: ISM, IEEE 802.11, 802.11b, 802.11g, 802.11n wireless LAN, IEEE 802.15.4-2006, Bluetooth, radio-controlled aircraft (strictly for spread spectrum use), microwave ovens, ZigBee
2483.5–2495MHz: Globalstar downlink and Terrestrial Low Power Service suitable for TD-LTE small cells[19]
2495–2690 MHz: Educational Broadcast and Broadband Radio Services[20]
2690–2700 MHz: Receive-only range for radio astronomy and space research
See also
Digital Audio Broadcasting and its regional implementations
Digital terrestrial television
Thing (listening device)




Tomislav Stimac, "". IK1QFK Home Page (vlf.it).