Computer Science Assignment - TSM321E Antenna

1. (3 pts) How is antenna gain developed?

2. (3 pts) If an isotropic antenna and Antenna X are located at the same distance from a receiver, fed with the same signal at the same power level, and the result is that the signal from Antenna X is 4 times as powerful as the signal from the isotropic, how would I characterize the gain of Antenna X?

3. (5 pts) What type of radiation pattern is represented by this plot?

Answer: ________________________

4. (5 pts) What type of radiation pattern is represented by this plot?

Answer: ______________________

5. (3 pts) An antenna whose gain increases with frequency for a given reflector size is a _________________ antenna.

6. (3 pts) The problem with very high gain antennas is that they are _____________________.

7. (5 pts) What type of radiation pattern is represented by this plot?

Answer: ______________________________

8. (5 pts) What is the beamwidth of the antenna in question 7?.

9. (3 pts) An omnidirectional antenna that exhibits gain over a dipole antenna is most likely a _____________________ antenna.

10. (3 pts) An antenna that includes a dipole driven element, a non-driven element that is longer than the driven element and one or more non-driven elements that are shorter than the driven element is a __________________ antenna.

11. (3 pts) An antenna that is a hollow tube closed at one end with a quarter wavelength antenna mounted inside is a ___________________ antenna.

12. (3 pts) In question 10 the non-driven element that is longer than the dipole element is called a _____________________.

13. (3 pts) In question 10 the non-driven element that is shorter than the dipole element is called a _____________________.

14. (3 pts) The three Fundamental types of feedlines are __________, __________& __________?

15. (3 pts) A feedline that is a hollow tube of rectangular cross section is what type?_____________

16. (3 pts) Generally speaking feedline loss ________________ as frequency increases.

17. (2 pts) True or False: compared to other fundamental feedline types RG-8 type has good loss characteristics. ____________

18. (2 pts) Generally speaking feedline loss ________________ as feedline size increases.

19. (5 pts) What is the loss of 145 feet of LMR-600 at 2.4Ghz? Show your work. Use the Feedline Loss Characteristics Chart on the last page.

20. (5 pts) An 85 foot cable run for a system that operates at 5.8Ghz must have loss that is less than 10dB. What are the choices for cable? Use the Feedline Loss Characteristics Chart on the last page. Answers without supporting calculations will only receive ½ credit.

USE THE ANTENNA BEAMWIDTH & GAIN SPECIFICATIONS ON THE LAST PAGE FOR PROBLEMS 21-23

21. (10 pts) A radio link has +29dBm of transmitter power when using 802.11g at 54Mbs on a frequency of 2.450Ghz. The receiver sensitivity is -85dBm. The left hand site has 75 feet of RG-8X feedline and the right hand site has 45 feet of RG-8X feedline. Each site has an omnidirectional antenna. Path loss is 117dB. What is our received signal strength? Does the link work? Do we meet good engineering standards? Show your calculations to support your answer.

Tx: +___dBm

Rx: -___dBm

Tx: +___dBm

Rx: -___dBm

22. (10 pts) If we change the feedline in question 21 to LMR-600 on both ends does the link work and do we meet good engineering standards? Show your calculations to support your answer.

Tx: +___dBm

Rx: -___dBm

Tx: +___dBm

Rx: -___dBm

23. (10 pts) If we change the feedline in question 21 to LMR-600 on both ends and change the antennas to parabolic dishes does the link work and do we meet good engineering standards? What positive and negative effects would these changes have on system operation. Show your calculations to support your answer.

Tx: +___dBm

Rx: -___dBm

Tx: +___dBm

Rx: -___dBm

Feedline Loss Characteristics
	30Mhz	150Mhz	450Mhz	900Mhz	2.4Ghz	5.8Ghz
RG-8X	2	4.7	8.6	12.8	23.1	40.9
LMR-200	1.8	3.9	6.9	9.9	16.4	26.4
LMR-400	0.7	1.5	2.7	3.9	6.8	10.8
Belden 9913	0.8	1.7	3.1	4.4	7.7	13.8
LMR-600	0.421	0.964	1.72	2.5	4.4	7.3

Loss per 100 feet

Antenna Beamwidth & Gain Specifications
	Horizontal Beamwidth	Vertical Beamwidth	Gain dBi
Parabolic Dish	5O	5O	30
Backfire Dish	25O	25O	14
90O Sector	90O	9O	16
Omnidirectional	n/a	30O	11.8
Unidirectional	40O	40O	12