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Aircraft can approach an antenna from any direction, so antennas need to be omni ("all") directional in the horizontal plane.
Early on, the easiest way to get omnidirectionality was to use vertical polarisation, and it's also the simplest kind of antenna - a simple rod or wire (of the right length) works just fine.
Subsequent antenna design has produced omnidirectional antennas with horizontal polarisation, but there are no significant advantages, and the design/construction is more complex than a vertical equivalent.
What else can I help you with?
Would 154.400 mHz be vHf?
Yes.
Can you use a VHF radio to call a walkie-talkie?
A walkie-talkie refers to a portable radio. VHF range is usually 136 to 172 mhz and a portable will pick up if tuned to this range.
Why FM transmission is limited to line of sight?
the high frequency, it is in VHF band.
How far should a vhf transmitter be from another?
The distance between VHF transmitters depends on several factors, including their power output, terrain, and the frequency being used. Generally, to avoid interference, it's recommended to keep VHF transmitters at least a few kilometers apart, but this distance can vary. For specific applications, such as marine or aviation, regulatory guidelines or local regulations may dictate minimum separation distances. Always consult relevant standards and guidelines for precise requirements.
What vhf frequency is used for emergency?
The VHF frequency commonly used for maritime emergency communications is 156.8 MHz, designated as Channel 16 (also known as the international distress frequency). This channel is monitored by vessels and coast stations for distress calls and emergencies. In aviation, the emergency frequency is 121.5 MHz, which is also used for search and rescue operations.
Do miltary aircraft use vhf?
Almost all military transport and patrol aircraft use VHF.
What is the name of all Antennas on Cessna 172?
The Cessna 172 typically features several antennas, including the VHF communication antenna, VOR (VHF Omnidirectional Range) antenna, and the transponder antenna. Additionally, some models may have an ADF (Automatic Direction Finder) antenna and a GPS antenna. The specific configuration can vary depending on the aircraft's avionics package and modifications.
How can the transmission distance be increased?
Use LF or lower HF frequencies (rather than UHF or VHF), proper SWR tuning of antennas, radio amplification.
What has the author Valdis V Liepa written?
Valdis V. Liepa has written: 'Numerical approach for predicting radiation patterns of HF-VHF antennas over irregular terrain' -- subject(s): Antennas, Numerical calculations, Radio, Computer programs
What has the author C S Gledhill written?
C. S. Gledhill has written: 'VHF line techniques' -- subject(s): Wave guides, Microwaves, Antennas (Electronics)
What vhf channel should be used to issue a mayday if you are faced with a life-threatening emergency?
If you are in a boat the frequency is 156.8 Mhz, also known as channel 16. For an aircraft emergency the VHF frequency is 243.0 Mhz.
How can you tell the difference between a CB antenna and a VHF antenna?
The CB antenna is made for a limited band of frequencies and the VHF is a wide band antenna made for higher freqs. A CB antenna will not make a good tv antenna. A CB ant. is mounted on the vertical and tv ants. are mounted horiz. in the USA. VHF antennas are much smaller as they are for higher frequencies. Usually, they have many elements (rods) and will go from long in the back to short in the front. Certain CB antennas (beams) are mounted horizontally, but all of the elements are roughly the same length - and about twice as long as a VHF antenna. The elements on a horizontal CB antenna are roughly 18 feet from end to end.
What is gain of typical TV FM vhf only home antenna?
The actual numbers are not as important as the knowledge that generally speaking, the larger the antenna the more gain it will have. Three other main factors are the Distance from the transmitting antennas are from your location and the Height of your antenna above the ground and what Obstructions there might be between the two antennas.
Why is vhf considered the best way to call for help?
Because a VHF broadcast theoretically could reach thousands of people ! Additionally, if it's (for example) a marine or aircraft emergency, there are specific emergency channels, which are monitored 24/7 by professional people.
What is line of sight communication?
Line of sight communication is in the VHF and higher frequencies of the RF spectrum where the wavelength is to short to pass over structures and hills, the transmitter and receiver antennas must be in line of site
Why is Vhf radio considered the best way to call for help?
Because a VHF broadcast theoretically could reach thousands of people ! Additionally, if it's (for example) a marine or aircraft emergency, there are specific emergency channels, which are monitored 24/7 by professional people.
What has the author R D C Thoday written?
R. D. C. Thoday has written: 'A reflector unit for a 500 kW HF balanced screened feeder' 'Antennas for portable VHF-FM receivers'
