TV-reception antennas for VHF are constructed with cross wires supported at their centers. The ideal le for the cross wires is one-half the wavelength to be received, with the more expensive antennas having for each channel. Suppose you measure the lengths of the wires for particular channels and find them to 1.94 and 0.753 m long, respectively. What are the frequencies for these channels?

TV-reception antennas for VHF are constructed with cross wires supported at their centers. The ideal le for the cross wires is one-half the wavelength to be received, with the more expensive antennas having for each channel. Suppose you measure the lengths of the wires for particular channels and find them to 1.94 and 0.753 m long, respectively. What are the frequencies for these channels?

College Physics

1st Edition

ISBN:9781938168000

Author:Paul Peter Urone, Roger Hinrichs

Publisher:Paul Peter Urone, Roger Hinrichs

Chapter24: Electromagnetic Waves

Section: Chapter Questions

Problem 24PE: TV-reception antennas for VHF are constructed with cross wires supported at their centers, as shown...

See similar textbooks

Similar questions

A Marconi antenna, used by most AM radio stations, consists of the top half of a Hertz antenna (also known as a half-wave antenna because its length is /2). The lower end of this Marconi (quarter-wave) antenna is connected to Earth ground, and the ground itself serves as the missing lower hall. What are the heights of the Marconi antennas for radio stations broadcasting at (a) 560 kHz and (b) 1 600 kHz?
Figure 24.26 shows the interference pattern of two radio antennas broadcasting the same signal. Explain how this is analogous to the interference pattern for sound produced by two speakers. Could this he used to make a directional antenna system that broadcasts preferentially in certain directions? Explain. Figure 24.26 An overhead view of two radio broadcast antennas sending the same signal, and the interference pattern they produce.
(a) The ideal size (most efficient) for a broadcast antenna with one end on the ground is onefourth the wavelength (/4) of the electromagnetic radiation being sent out. If a new radio station has such an antenna that is 50.0 m high, what frequency does it broadcast most efficiently? Is this in the AM or FM band? (b) Discuss the analogy of the fundamental resonant mode of an air column closed at one end to the resonance of currents on an antenna that is one-fourth their wavelength.
A circular radar antenna on a Coast Guard ship has a diameter of 2.10 m and radiates at a frequency of 15.0 GHz. Two small boats are located 9.00 km away from the ship. How close together could the boats he and still he detected as two objects?
A Doppler weather radar station broadcasts a pulse of radio waves at frequency 2.85 GHz. From a relatively small batch of raindrops at bearing 38.6 east of north, the station receives a reflected pulse after 180 s with a frequency shifted upward by 254 Hz. From a similar batch of raindrops at bearing 39.6 east of north, the station receives a reflected pulse after the same time delay, with a frequency shifted downward by 254 Hz. These pulses have the highest and lowest frequencies the station receives, (a) Calculate the radial velocity components of both batches of raindrops. (b) Assume that these raindrops are swirling in a uniformly rotating vortex. Find the angular speed of their rotation.
Integrated Concepts Assume the mostly infrared radiation from a heat lamp acts like a continuous wave with wavelength 1.50 (m. (a) If the lamp’s 200W output is focused on a person’s Shoulder, over a circular area 25.0 cm in diameter, what is the intensity in W/m2? (b) What is the peak electric field strength? (c) Find the peak magnetic field strength. (d) How long will it take to increase the temperature of the 4.00-kg shoulder by 2.00°C, assuming no other heat transfer and given that its speci?c heat is 3.47103J/kgC ?
Radio telescopes are telescopes used for the detection of radio emission from space. Because radio waves have much longer wavelengths than visible light, the diameter of a radio telescope must be very large to provide good resolution. For example, the radio telescope in Penticton, BC in Canada, has a diameter of 26 m and can be operated at frequencies as high as 6.6 GHz. (a) What is the wavelength corresponding to this frequency? (b) What is the angular separation of two radio sources that can be resolved by this telescope? (c) Compare the telescope’s resolution with the angular size of the moon.
TV-reception antennas for VHF are constructed with cross wires supported at their centers, as shown. The ideal length for the cross wires is one-half the wavelength to be received, with the more expensive antennas having one for each channel. Suppose you measure the lengths of the wires for particular channels and find them to be 1.94 and 0.753 m long, respectively. What are the frequencies for these channels?
3. TV-reception antennas for VHF are constructed with cross wires supported at their centers, as shown in the figure. The ideal length for the cross wires is one-half the wavelength to be received, with the more expensive antennas having one for each channel. Suppose you measure the lengths of the wires for particular channels and find them to be 2.57 and 0.706 m long, respectively. What are the frequencies (in Hz) for these channels? f2.57 m= Hz f0.706 m= Hz
#2: The ideal size (most efficient) for a broadcast antenna with one end on the ground is one-fourth the wavelength (λ/4) of the EM wave being sent out. If a new radio station has such an antenna that is 50.0m high, what frequency does it boradcast most efficiently? Is this in the AM or FM band. This analogous to what phenomenom encountered in our study of sound wave? (Note: AM band ranges from 540 to 1600 kHz, and FM band is between 88 to 108 MHz)
The 21-cm line of atomic Hydrogen is very common throughout the Universe that some scientists suggest that if we want to send messages to aliens we should use the frequency of π times this frequency (why?). What is the frequency they suggest to use? A. 4.49 GHz B. 1.43 GHz C. 2.75 GHz D. 3.62 GHz Is the answer B? The use of frequency π times is to avoid destructive interference such that the radio message could travel through space without distortion? Thank you very much!
A friend buys a used pickup truck that comes complete with a CB radio. However, the antenna is broken off, and your friend asks you to help make one out of a steel rod that he will affix to the rear bumper. You know that the frequency is 27.7 MHz and that the antenna must be a quarter-wavelength long. How long should you make the rod? L = m