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What else can I help you with?
How many directors and reflectors in Yagi Uda antenna?
yagi udda antenna has only one reflector...but it has many directors...depending upon gain and efficiency...the length of reflector is normally...more than one-half of wavelength... and directors have a length less than one-half of wavelength...
Why High frequency reduce the size and weight of components?
The concept is, greater the frequency less will be the size of antenna and weight. For example the Mobile Phone uses the half wave dipoles antenna. There is no exact formula for calculating these antennas. The problem is that there are several factors that affect the antenna. Fortunately there is a starting formula for these types of antennas. For center fed, wire dipole antennas, the formula is length of antenna = 468/freq (MHz). Mobile phone in GSM working on the frequencies 900 MHz and 1800 MHz so put the values in the formula you get your answer. If you move further in the frequency band the size will be more small.
Why antenna height is at least quarter wavelength for radiating from it?
A transmitter antenna is a tuned circuit and it can be very complex and it even get more difficult at higher frequencies, if it's not a 1/4 wave length of the transmitter frequency it is un tuned and you will have some of your RF power radiated back to the transmitter, that is called SWR, for Standing Wave Ratio and it will damp the RF that is radiated from the antenna and if the SWR is to high it can damage the transmitters final stage. It don't have to be the real physical 1/4 or 1/2 wave and it can even be 5/8 of the wavelength but then a L/C circuit have to be inserted at the input side of the antenna to tune the antenna to the correct frequency one antenna can even be used for two different frequencies, then a L/C tuning circuit have to inserted at a 1/4 wave length of the higher frequency , this type of antenna is used in duplex systems, like a cell phone.
Why you are using capacitive hat in short antennas?
Capacitive hats are used to alter the distribution of the current on a short antenna so that the antenna current is not concentrated near the ground. A whip or short antenna can be modeled as a series of LC circuits in which the capacitance per unit length is highest near the base and the inductance per unit length is highest near the top. A capacitive hat simply adds capacitance to the antenna. It basically makes the antenna seem longer, but maximum current is still at the base.The reason why you'd want to make your short antenna longer, is to obtain the antenna's resonance frequency. The length required to do this is a quarter or a half of the wavelength of the radio wave that it's receiving. At resonance, the electrical resistance of the antenna drastically drops, which effectively increases the Q factor, or quality factor, of the resultant output signal. The term Q factor is simply a measurement of how good the clarity and stability of the output signal is, the higher the better when dealing with radios and televisions.Of course, instead of using a capacitive hat on your antenna, you could always physically lengthen the antenna itself. However, considering that commonly-used radio waves can be up to 10 m (33 ft) long, your antenna would have to be about 8 feet long, which would make using your radio a bit awkward.
What is slenderness ratio structural engineering?
The slenderness ratio is the ratio between the height or length of a structural element (such as a column, or strut) and the width or thickness of the element. For example, if a rectangular column is 6m high, and 400mm by 600mm in cross-section, then its slenderness is 6000/600 = 10 in one direction and 6000/400 = 15 in the other direction. The higher the slenderness ratio, the more slender the structural element is. How slender a structural element is allowed to be depends upon the material it is made from. Steel can be more slender than concrete, for example. In structural engineering calculations, the slenderness is often denoted as the element's "effective" length divided by something called the radius of gyration. The radius of gyration is a measure of the average distance of the material from the centroid (centre of gravity) of the element's cross section. This can be calculated as r = (I/A)0.5, where I is the second moment of area, or second moment or inertia, of the cross section and A is the area of the cross section. The effective length of an element is determined by how it is fixed at its ends. The effective length is the length of the column that will form half a sine wave if it buckles. If it is "pinned", or has hinged ends, the effective length is the true length of the element. If it is a cantilever (fixed at one end but free at the other), the effective length is twice the true length. If it is fully fixed at both ends the effective length is 0.7 times the true length, but this is in reality very difficult to achieve, so often a real structural element is considered to be only nominally fixed and the effective length is taken to be 0.85 times the true length.
What is the half wave dipole?
effective height of half wave dipole antenna
What is the operational frequency of half wave dipole antenna?
Its resonant frequency is where its length is half a wavelength, so for 100 MHz the wavelength is 3 metres and a 1.5-metre long dipole is resonant. A dipole antenna can be used for many applications within a band of 10-20% around the resonant frequency.
What are the disadvantages of half wave dipole antenna?
The half-wave dipole antenna has several disadvantages, including its limited bandwidth, which can restrict its effectiveness across a range of frequencies. Additionally, it has a relatively low gain compared to other types of antennas, making it less effective for long-distance communication. The dipole's radiation pattern can also lead to blind spots, limiting its directional capabilities. Lastly, it requires a specific length to function optimally, which may not be practical in all installation scenarios.
What is the value of radiation resistance of half wavelength dipole antenna?
36 ohm
Can you make a comparison between the dipole antenna and short dipole antenna?
A short dipole has lon the other hand, A half-wave dipole doesn't strictly satisfy our criterion l for being "short.Eng: Ibrahim Mawdhah, yemenمهندس : ابراهيم معوضه
What is the perfect length of antenna for a radio signal of 100 MHz?
The half-wave, center-fed 'dipole' antenna is probably the antenna that's simplest to design, and easiest to build and operate. For 100 MHz, it's a single wire, supported at its ends and insulated from the supports, hung horizontally, opened and connected to a 75-ohm coaxial cable at its center, with an overall length of 4 feet 11 inches (1.5 meters).
What length of dipole in relation to its wavelength in meters or khz?
There are several kinds of dipole; the most common is the half-wave dipole. Its total length is fairly close to half the wavelength of the design frequency. The length needs to be adjusted slightly to compensate for the thickness of the elements and for end-effects. If the length is wrong by ten or twenty percent it will alter the feed impedance, but have little effect on the gain.
Find the optimum wavelength and frequency for a half-wave dipole of length 10 m?
15mhz
What is the formula for a quarter wave dipole antenna?
The length of a quarter wave for constructing one end of a dipole is: 234/MHz = feet of wire. For instance if you have an 80 meter ham radio transceiver and want to construct a dipole to match a frequency of 3.56 MHz (the low power calling frequency) then 234/3.56 = 65.7 feet Next buy a spool of speaker wire, mark off 65 and 3/4 feet, and pull apart the two wires until you reach the mark. Now you have a half wavelength dipole that resonates near 3.56 MHz. Start broadcasting in Morse code and I will meet you on the air! Sandy, KB3EOF
What is the optimum length am antenna?
[ (234) divided by (station frequency in MHz) ] feet, hanging vertically.
How do you make a 11 meter dipole antenna?
A wavelength of 11 meters puts you in the citizen's band. Most equipment uses vertical antennas, and so should you to have the best reception on both ends of a call. There are many ways to assemble a dipole, from a straight wire, to a ladder line, to a coaxial bazooka, to . . . . And many ways to connect your feedline to the radio transceiver: with or without a balun, with or without a balanced feedline, and so forth. Try Googling for dipole antennas, and see what you come up with.
What is Radiation pattern of have wave dipole is?
In open space, infinitely far from material objects, the radiation pattern of a half-wave dipole is a torus (donut), with the radiator (wire) passing straight through the center of the hole. The field strength is maximum in all directions perpendicular to the wire, and zero in the directions off the ends of the wire. The peak field strength is +2.2 dB relative to isotropic.
