Free space

A free space LOS (Line of Sight) microwave link operating at 10 GHz consists of a transmit and receive antenna each having gain of 25dB. Calculate the path loss of the link and received power of 100 Km distance.

A microwave link includes two sites that are 10 km apart and uses a center frequency of 9 GHz. On either transmitter or receiver side, a 100-m transmission line that has an attenuation per unit length of 0.01 dB/m is connected to an amplifier and a parabolic reflector antenna. Other losses caused by connectors and insertions incurred on one side amounts to 3 dB. Antenna has a power gain of 20 dB. If the output of the transmitter amplifier is 30 dBm, what is the received signal level (in dBm) at the input of the receiver amplifier?

1. Discuss in detail the construction of a Directional Coupler. 2. Discuss in detail whether the incident energy can be sampled or not with pick up probe at port ‘4’.

Derive the formula for maximum usable frequency and skip distance assuming earth is perfectly flat.

Determine the fade margin for the following conditions: distance between sites, D = 40 km; frequency, f = 1.8 GHz; smooth terrain; humid climate; and a reliability objective 99.99%

A satellite at an altitude of 37654 km transmits a signal of 17 GHz to a ground station directly below it. The following data is given. • Total atmospheric losses = 40dB • Transmit antenna gain = 55dBi • Receiver antenna gain = 60dBi • Signal to noise ratio of received signal = 6dB • Receiver signal noise power = 25pW • Receiver sensitivity = -90dBW I. Calculate the power transmitted. II. Find the Fade Margin for the link and comment on your result.

A circular loop, of loop radius λ/30 and wire radius λ/1000, is used as a transmitting/receiving antenna in a back-pack radio communication system at 10 MHz. The wire of the loop is made of copper with a conductivity of 5 .7 ×10 7 S/m. Assuming the antenna is radiating in free space, determine the(a) radiationresistan ce of the loop; (b) loss resistance of the loop (assume that its value is the same as if the wire were straight ); (c) input resistance; (d) input impedance; (e) radiation efficiency.

As a technician, you are responsible for the construction of a 10km optical communication link between Pelonomi Hospital and National Hospital in Bloemfontein. The following link specifications are available:Transmitter output power: 15mWCommercially available optical cable length: 2kmOptical cable attenuation: 1.2dB/kmSplice attenuation: 0.1dB/kmLight transmitter-to-cable loss: 1.5dBCable-to-photo detector loss: 1.5dBSafety margin: 7dB Determine the minimum receiver sensitivity in microwatts needed to reliably detect a transmitted signal.

A. If Satellite with a radius of 5.3m trans mitted a message at the frequency of 1.3 MHz to earth station. Determine;i. The wavelength, and time, in hour of the transmissionii. The centrifugal force of the satelliteiii. The attenuation of the transmission B. The wavelength of a signal transmitted at 1000MS-1 is 700M. Determine the period of the transmissionC. Analyze the conditions that can lead to satellite path diversityD. Explain handoff and discuss three types of satellite handoff

Use the free space model to compute the free space path loss for a 900 MHz signal over a distance of 200 meters. Express your answer in dB. state the answer in the correct units and show all your computations to receive credit

A cellular radio transmitter has a power output of 3 W at 800 MHz. It uses an antenna with a gain of 3 dBi. The receiver is 5 km away, with antenna gain of 12 dBi. Ignoring feedline losses and mismatch, calculate (a) the EIRP in dBW  (b) the free space path loss,    (c) the power delivered to the receiver in W and dBm

AGILA satellite is located 36000 km above the earth’s surface. Assuming free space condition, what is the path loss in dB of the signal if the operating frequency is 3 GHz. (Use two decimal places for the final answer)

Multiple Choice    For RF line of sight or LOS communication, ____ of the first Fresnel zone must be clear of obstacles. 50% 60% 70% 80%   What is the maximum line-of-sight distance (D) between a paging antenna 800 ft high and a pager receiver antenna 40.5 ft off the ground? 35 mile 49 mile 40 mile 38 mile   IEEE 802.11 ___ devices can only use MIMO antennas. a b g n   In Yagi antenna, reflector is ____ greater than λ/2. 10% 7% 12% 5%   What is the frequency range of Sky waves? 3 KHz to 2 MHz 2 MHz to 30 MHz 30 MHz to 300 GHz 3 GHz to 30 GHz   What is the impedance of Folded Dipole antenna? 377Ω 73Ω 5Ω 300Ω   Standing wave is the composition of __________ voltage. Incident & load Reflected & load Incident & Reflected None of the above   ______________ is obtained by dividing the speed of light (or radio) wave in a vacuum, and the speed of light (or radio) wave in the medium that causes the wave to be bent. Diffraction Index Reflection Index Refraction Index…

1.) A communication system is defined below:Transmitter Power: = 45 dBm; Frequency = 1 GHzTransmit Antenna: Gain = 12 dB, height above ground = 50 meters;Receive Antenna: Gain = 6 dB, height above ground= 2.5 metersFind the received power (in dBm) at a range of 4 kilometers:a. using the free-space range equation b. using the near-earth range equation Using the results of the calculations in a & b above: c. determine the best prediction of the received power (in dBm) at the 4 kilometer range. answer should be  a) -41.15 b) -39.1 c.) near FS

How would you find the needed increase of an antenna area of a satellite if it increased altitude from 600km to 6,000km. This would be an alternative to increasing transmission power. The area of the satellite at 600km is 4m x .70m (2.8m^2). What new antenna area would be needed at 6,000km?

A/ Choose the correct answer1: ______ Sub-system collect data derived from many sensors on theSat and send it to the earth station.a) Telemetry b) thrust c) antenna d) stabilization2:  ______ GEO Sat are required to cover the entire eartha) Two b) three c) four d) five3: An Amp has a noise temperature of 580ok, the equivalent is noisefigure in dB approximately is ______  .a) 2 dB b) 3 dB c) 4 dB d) 5 dB4: In a practical SAT, the transponder bandwidth is about ______  .a) 500 MHz b) 600 MHz c)700 MHz d) 800 MHz5:  ______ Sub-system keeps the Sat antenna pointing in the rightdirectiona) antenna b) thrust c) stabilization d) Telemetry6:  ______ Sat, it compromises between the lower and GEO. Sat it rotatesat 8000 km to 18000 kma) HEO b) MEO c) LEO7: An earth station receiver antenna with radius of 15m, efficiency 68%at operating frequency of 4.15 GHz, if the system noise temperatureis 88ok then the value of CNR in dB at the antenna approximatelyis ______  .a) 20 dB b) 30 dB c) 40 dB d) 50…

2. A system is being designed to use a 30 GHZ link with a 300HZ bandwidth to receive signals from a navigation spacecraft at an altitude of 20,200km, with a maximum slant range of 24,700km.  The satellite transmitter-antenna gain is 25db and the handheld unit receiver gain is 5db.  The transmitter power will be 18W.  If the handheld receiver temperature is 500K, will this be an effective link (S/N at least 10 or 10db)?  If not, what could you change to improve the link?

A typical glass core optical fibre has a specified transmission loss factor of 0.046 dB/km due to Rayleigh scattering. At a wavelength of 1000 nm, the glass material possesses an approximate fictive temperature value of 758K, an isothermally compressibility parameter of 8.4 × 10-11 m2/N, and a photo-elastic coefficient of 0.245

Which row represent the most stable system and why? nyquist and root locus plot attached.

Design a dielectric-filled rectangular waveguide for transmission of electromagnetic power at 2.45 GHz. Find the maximum power the waveguide can transmit. Use an electric field safety factor of 10. Neglect conduction losses. The material filling the waveguide is nonmagnetic with zero conductivity, and has r = 2.1; its breakdown electric field is 6x107 V/m.

Multiple Choice directions: Circle the letter of the answers 7. This is a special microwave coaxial cable used in the lower microwave bands L, S, and C. a. Flexible coaxial b. All of the above c. Hard line cable d. Braided coaxial 8. The practical microwave region is in the vicinity of a. 1-10 GHz b. 1-20 GHz c. 1-300 GHz d. 1-30 GHz 9. In a hybrid ring, if the signal is applied at port 1, which port has no output? a. 3 b. 2 c. 1 d. 4 Note: Explanation is not needed just provide the correct answers for each number.

What length of a 50 ohm open circuit transmission line is equivalent to a 1 uH inductor at 50 MHz?

Explain MUF and give any method forcalculation. A high frequency radio link has tobe established between two points at a distanceof 2500km on earth surface. Considering theionospheric height to be 200 km and itscritical frequency is 5 MHz. calculate theMUF for the given path

What length of a 50 ohm short circuit transmission line is equivalent to a 1 uH inductor at 50 MHz?

The effect of rain attenuation at high frequencies is minimized if vertical polarization is used. Select one: True  False