TABLE OF CONTENTS In response to many requests, this appendix comprises problems from both the subject matter in the EW 101 and EW 102 books. Each of these problems is worked to 1-dB resolution, using the corresponding forms of the formulas. Where it is appropriate to use a nomograph or graph from the text, it is copied and its use to solve the problem is shown.
When antenna gains are given, they refer to the gain in dBi in the direction of the receiver (for transmit antennas) and in the direction of the transmitter (for receiving antennas) unless otherwise stated in the problem.
In these problems and solutions, "log" is taken to mean "log 10." Remember that decibel formulas require that inputs be made in the proper units. These units are stated along with the formulas in the referenced sections.
Each of these problems is from material in EW 101. The section numbers listed are the sections of the EW 101 book where the formulas and explanations are found.
| Q: | 101 1: Convert 4W into dBm. ?(Section 2.1.2) |
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Answers
| Q: | 4W / 1 mW = 4,000 10 log 10(4,000) = 36 dBm |
| Q: | 101 2: Convert 70 dBW to dBm. ?(Section 2.1.2) |
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Answers
| Q: | 1W = 1,000 mW 10 log (1,000) = 30 dB 70 dBW + 30 dB = 100 dBm |
| Q: | 101 3: Calculate the line-of-sight spreading loss for a 1-GHz signal at 50 km. |
