61444774 the microwave design procedure

7/28/2019 61444774 the Microwave Design Procedure

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THE DESIGN PROCEDURE

As a starting point, it is assumed that the preliminary facility planning (including

operational requirements, traffic studies, expansion potential, reliability requirement and

cost studies) has been finished to such degree that the points to be served have been

fixed, and the required system capacity has been determined.

The following are the methods in designing a microwave communication system .

1. Choose two terminal sites (Site A and Site B) for the proposed microwave

system considering the requirements and specifications.

2. Determine the microwave path length between the sites (distance from Site A to

Site B) using the Geographical Information System (GIS) or a topographical or

any map based software.

3. Get the longitude and latitude of Site A and Site B using the GIS or a

topographical map or any map based software. Determine the 10 Technical Site

considerations for each site from data obtained from the LGU¶s.

4. Measure the azimuth, the angular position with respect to the earth¶s true north,

for each of the two terminal sites.

5. Determine the elevation of Site A and Site B using the GIS or a topographical

map or any map based software.



6. Create a Radio Path Profile, from Site A to Site B by getting the appropriate

distance and elevation of the obstruction samples between the corresponding

sites.

7. Calculate the Height Due to Earth¶s Curvature (Hk) for each of the obstruction

samples.

8. Select a microwave operating frequency in Gigahertz range.

9. Select the type of transmission diversity used.

10. Solve for the Fresnel Zone Radius (Fz) on the tip of each obstruction sample.

Calculate the Total Obstruction Height (TOH) for each of the obstruction samples

by summing their corresponding Height Due to Earth¶s Curvature (Hk), Radius of

the first Fresnel Zone (Fz), Obstruction elevation, and height of trees.

11. Sketch the final Radio Path Profile from Site A to Site B, emphasizing the

recorded elevation samples, the main obstructions, and the sites.

12. Draw the K-curve.

13. Find the necessary specifications of microwave equipments that will match the

chosen frequency band.

14. Solve for the equal Antenna Heights, for Site A and Site B.

15. Solve for the corresponding Waveguide Lengths (Wglength) by adding the antenna

height and the distance from the tower to the radio room, minus the waveguide

vertical clearance of 10 meters.

16. For each system, solve the Waveguide Loss. It is equal to the product of the

waveguide lengths and the waveguide attenuation value taken from the

equipment specifications.



17. Solve for the Total Fixed Losses (TFL), which is equal to the sum of the rigid

waveguide loss, flexible waveguide loss, connector loss, radome loss, combiner

loss, and circulator loss.

18. Solve for the path attenuation or free space loss (Lp) from Site A to Site B.

19. Calculate the overall system loss for the corresponding system.

20. Calculate the equivalent Fade Margin (FM) of the system assuming 99.9998%

reliability.

21. Solve for the separate Receive Signal Level (RSL) by adding the calculated Fade

Margin (FM) to the minimum RF input (Receiver Threshold) taken from the

equipment specifications of the transceiver used.

22. Solve for the separate Total Gain of the system.

23. Calculate the diameter of the parabolic antenna for the system..

24. Solve for the New Gain of the system using the final antenna diameter selected

from the available list of parabolic antenna found in the antenna specification

sheet.

25. Calculate the Net Path Loss (NPL) of the system by subtracting the total New

Gain from the Total System Loss.

26. Solve for the corresponding Median Receive Power (MRP) by subtracting the Net

Path Loss (NPL) from the minimum Transmitter Power (Po).

27. Solve for the Actual Fade Margin (FM ACTUAL) of the two systems by subtracting

the Receiver Threshold from the MRP.

28. Calculate the equivalent System Reliability for Non-Diversity (Undp) basing on the

newly calculated Fade Margin (FM ACTUAL).



29. Calculate the equivalent Actual Reliability (R ACTUAL) using the computed value of

System Reliability for Non-Diversity (Undp).

30. Using frequency diversity, calculate the Improvement Factor (Ifd), Diversity

Annual Outage Probability (Udiv), New Reliability and Fade Margin with the use

of diversity.

31. Calculate the corresponding Waveguide Volume (Vwg) by multiplying the

calculated Waveguide Length (Wglength) to the specified Transmission Line

Volume per 1000 ft.

32. Solve for the Total Voice Channel (VCtotal) using STM-1 + E1 capacity.

33. Solve for the Bandwidth using 128 QAM modulation technique. Illustrate the

corresponding Frequency Spectrum.

34. Solve for the Back Up Power Calculations.

35. Specify the Generator Set Rating.

61444774 the microwave design procedure

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