After Steps 1-4 are completed in Ex. 3.6 and the link distance is 25 kilometers, the path

loss is

Select one:

a. 25 dB

O b. 128 dB

O c. 11 dB

• d.80 dBm

Exercise 3.6

Link Budget and Fade Margin

In this exercise, you will use a Microsoft Excel file LinkBudget.xls to calculate a link budget and fade margin. You will need Excel installed on your computer. Save the LinkBudget file.

1. Open the Excel file from your desktop.
2. In row 10, enter a link distance of 25 kilometers. Note that the path loss due to a 25 kilometer link is now 128 dB in the 2.4 GHz frequency.
3. In row 20, enter 128 for path loss in dB.
4. In row 23, change the radio receiver sensitivity to -80 dBm. Notice that the final received signal is now -69 dBm, and the fade margin is only 11 dB.
5. Try increasing the "radio transmitter output power" to see how the connection would fare and to determine how much power would be needed to ensure a fade margin of 20 dB. You can also change the other components such as antenna gain and cable loss to ensure a fade margin of 20 dB.