Description : This type of transmission permits communication in the frequency range from 30 to 60 MHz and over distances from about 1000 to 2000 km. A. Troposcatter B. Ionospheric scatter C. Ducting D. Microwave
Last Answer : B. Ionospheric scatter
Description : Type of transmission path that permits communication in the frequency range from 30 to 60 MHz and over distances form about 1000 to 2000 km. A. Ducting B. Ionospheric scatter C. Microwave D. Troposcatter
Description : Whenmicrowave signalsfollowthe curvatureofthe earth,thisisknownas a. the Faraday effect b.ducting c. tropospheric scatter d. ionospheric reflection
Last Answer : b.ducting
Description : What condition occur when the refractive index of the air decreases with height much more rapidly the normal? A. Refraction B. Superrefraction C. Subrefraction D. Diffraction
Last Answer : B. Superrefraction
Description : One ofthe followingconsistsof nonresonant antennas: a.The rhombic antenna b. The folded dipole c. The end-fire array d. The broadside array
Last Answer : a.The rhombic antenna
Description : VLFwaves are used forsome type ofservices because a. of the low powers required b. the transmitting antennas are of convenient size c. they are very reliable d. the penetrate the ionosphere easily
Last Answer : c. they are very reliable
Description : Anantenna thatis currentlypolarized usthe a. helical b. small circular loop c. parabolic reflector d. Yagi-Uda
Last Answer : a. helical
Description : Indicate the antenna thatisnotwideband: a. Discone b. Folded Dipole c. Helical d. Marconi
Last Answer : d. Marconi
Description : Whichofthe followingantennasis best excited fromawaveguide? a. Biconical b.Horn c. Helical d. Discone
Last Answer : b.Horn
Description : The output waveform produced due to time base generator in a CRO is a) saw tooth b) sinusoidal c) linear d) helical
Last Answer : a) saw tooth
Description : Which of the following antennas is best excited from a waveguide? A. Biconical B. Horn C. Helical D. Discone
Last Answer : B. Horn
Description : Which of the following antennas receives signals equally well from all directions in a horizontal plane? A. Hetz antenna B. Vertical Marconi antenna C. Yagi antenna D. Helical antenna
Last Answer : B. Vertical Marconi antenna
Description : As electromagneticwavestravelinfree space, onlyone ofthefollowingcan happento them: a. absorption b. attenuation c. refraction d. reflection
Last Answer : b. attenuation
Description : Which of the following phenomena provides a convincing proof for wave nature of radiation a) Reflection b) Refraction c) Polarization d) Interference and diffraction
Last Answer : d) Interference and diffraction
Description : ____ is a term given to the region where superrefraction occurs. A. Strata B. Duct C. Isothermal region D. Tropospheric region
Last Answer : B. Duct
Description : What do you call the increase of temperature with height? A. Temperature inversion B. Normal inversion C. Ducting D. Superrefraction
Last Answer : A. Temperature inversion
Description : Which propagation method is known as special case of skywave? A. Space wave B. Troposcatter C. Ground wave D. Direct wave
Last Answer : B. Troposcatter
Description : A means of beyond the line-of-sight propagation of microwave signal. A. Space wave B. Microwave link C. Troposcatter D. Point-to-point
Last Answer : C. Troposcatter
Description : The angle of elevation of the antenna beam is 20°. Calculate the transmission-path distance for an ionospheric transmission that utilizes a layer of virtual height 200 km. Use flat-earth approximation. A. 966 km B. 2100 km C. 1100 km D. 405 km
Last Answer : C. 1100 km
Description : What ionospheric layer has a daytime approximate critical frequency of 8 MHz? A. F2 layer B. F1 layer C. E layer D. D layer
Last Answer : A. F2 layer
Description : What height of an ionized layer is determined from the time interval between the transmitted signal and the ionospheric echo at vertical incidence? A. Virtual height B. Apparent height C. Actual height D. Effective height
Last Answer : A. Virtual height
Description : What is the refractive index of an ionospheric layer with 100x105 free electrons per m3 ? Assume frequency to be at 20 MHz. A. 0.99 B. 0.15 C. 0.78 D. 0.85
Last Answer : A. 0.99
Description : Where does the greatest amount of ionospheric absorption occur in the ionosphere?
Last Answer : Where ionization density is greatest.
Description : Explain ionospheric propagation with neat sketch. Explain two properties of layers of ionosphere.
Last Answer : Diagram : Explanation: The transmitted signal travels into the upper atmosphere where it is reflected back to earth due to the presence of layers called as ionosphere in the upper ... having highest electron density of all layers, due to this F2 layer remains present at night time.
Description : Please ripley me due to emergency
Last Answer : To calculate the flux density in the ring, you need to use the following formula: B = (μ * I * N) / (2 * π * r) where: B is the flux density in the ring (in teslas) μ is the relative permeability ... 2 * π * 0.127 m) = 0.53 T So the flux density in the ring would be approximately 0.53 teslas.
Description : Can you help me solve my electrical mystery?
Last Answer : Any signs of animal life? They can get in the walls and chew on the wires. Or is it the entire area served by that breaker? The breaker could be bad. It happens with anything mechanical.
Description : How to tell if a power strip is burned out?
Last Answer : answer:Personally, I would either toss it, or down grade it to outdoor use only. I wouldn’t take a chance with it in the house. Yes, you can let it cool down, then test it again. But a failure is a failure. Does it have a reset button? What price range did you pay?
Description : I accidently soaked an extension cord. Is it safe to use it again after letting it dry out for awhile?
Last Answer : The plug end is easier to dry out than the socket end get out your blow-dryer and set it to high and blow the end that got wet for a while. That will get most of the water off/out of ... up or sputter. Most modern extension cords are pretty watertight so there shouldn't be any water down the wire.
Description : How can a solar array power source be bypassed when the batteries run low?
Last Answer : Ah got it. If anyone else is interested, you need an “automatic transfer switch” – or get a manual one for that mad scientist charm.
Description : How to stop a signal going through a wire?
Last Answer : Use a switch or a variable resistor
Description : Air conditioning will not turn on, is it electrical?
Last Answer : Pull the Thermostat off the wall and see if it is connected correctly to the AC switch. There should be no dangling wires, and the post labeled for the AC should have an attached wire.
Description : What is the speaker driving voltage of an amplifier?
Last Answer : I have to ask WHY? That said, Speakers and a light bulb are two different types of load, and the the lights will probably fry the output transistor.
Description : Why is my Garbage disposal leaking water from the bottom?
Last Answer : Replace it. The seal is leaking, and most cases it is just not worth the cost and work, quicker and cheaper to replace it .
Description : Have you ever taken a shower or bath during an electrical storm?
Last Answer : I’ve heard this rumor, and I too question it’s validity. I mean, if electricity can’t travel up a stream of urine (See mythbusters) I’m pretty sure it couldn’t travel through a shower stream. Perhaps through the drain? In either case, I’ve taken a shower in a storm before, and.. well, you see?
Description : Electrical breaker box is buzzing-why??
Last Answer : No! Do not upgrade the breaker. The wire must also be upgraded if you do. Try plugging it in a different room. Is the problem still there?
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