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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
Wiki User
∙ 12y ago
Wiki User
∙ 15y agoThe basic formula for a half wave dipole is:
L (length in feet) = 492/f (frequency in Mhz (1,000,000 Hz)
Divide this by 2 for a quarter wave antenna.
So for 40 meters (say 7.1 Mhz) the length would be 492/7.1
= 69.2/2 = 34ft & 7 3/4 ins.
In practice, because of "end effect" the antenna can be shortened an inch or so.
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What is the half wave dipole?
effective height of half wave dipole antenna
How loop antenna and dipole antenna can be used interchangeably?
A full-wave loop antenna can be interchanged with a folded dipole without much difference. The input impedance is similar and the only difference is in the directivity: a full wave loop radiates along the axis of the loop, while a vertical folded dipole is omnidirectional.
Radiation resistance of quarter wave monopole antenna is?
The radiation resistance of quarter wave monopole is 36.5 ohms
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.
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
The most appropriate value of the radiation resistance of a quarter wave monopole antenna?
The radiation resistance of a quarter wave monopole over a ground plane is 36.5 ohms.
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.
End fire antenna?
end-fire antenna = surface-wave antenna
What is the bandwidth of half dipole antenna?
The polar pattern for a half lambda aerial is a toroidal (doughnut) shape with the aerial in the centre of the toroid when mounted in free space a half wave above the ground. The half wave is an omni-directional aerial and produces zero gain.
Which antenna is best excited by a wave guide?
Horn Antenna is best exited by waveguide
Why does the rav4 have an antenna?
The Rav4 has an antenna for the same reason that most vehicles have an external antenna, to optimize radio wave reception.
How do you use lecher antenna?
To get the wave signal
