300-360 · Question #81
You have a multinational customer that would like you to perform a wireless site survey for a new manufacturing facility in Singapore. They have had a local vendor install a point-to- point wireless…
The correct answer is D. Change the radio power to 13 dBm. The current EIRP is 7 dBm (TX power) + 7 dBi (antenna gain) = 14 dBm. Dense fog introduces additional RF attenuation and increases the required link margin. The regulatory authority in Singapore (IMDA) limits 2.4 GHz EIRP to 100 mW (20 dBm). Increasing TX power to 13 dBm yields…
Question
You have a multinational customer that would like you to perform a wireless site survey for a new manufacturing facility in Singapore. They have had a local vendor install a point-to- point wireless bridge link between two buildings 1 km apart. The ground between the buildings is flat but because facilities are in the mountains, dense fog is an issue. There are no line of sight issues between the buildings. The link is experiencing errors and throughput issues. Currently the two radios are set to operate at 2.4 GHz and the transmit power is set to 7 dBm with 7 dBm antennas. What do you need to take into consideration when performing the site survey for this link?
Options
- AChange the radio power to 17 dBm.
- BChange the radio power to 20 dBm and replace with a 16 dBm antenna.
- CChange the radio power to 29 dBm.
- DChange the radio power to 13 dBm.
How the community answered
(33 responses)- A12% (4)
- B6% (2)
- C21% (7)
- D61% (20)
Explanation
The current EIRP is 7 dBm (TX power) + 7 dBi (antenna gain) = 14 dBm. Dense fog introduces additional RF attenuation and increases the required link margin. The regulatory authority in Singapore (IMDA) limits 2.4 GHz EIRP to 100 mW (20 dBm). Increasing TX power to 13 dBm yields an EIRP of 13 + 7 = 20 dBm - the maximum legally permitted - providing 6 dB of additional link budget to overcome fog-induced fade without violating local regulations. Choice A (17 dBm + 7 dBi = 24 dBm EIRP) and Choice C (29 dBm) both exceed regulatory limits. Choice B (20 dBm TX + 16 dBi antenna = 36 dBm EIRP) far exceeds permissible limits. The key consideration is maximizing power within the regulatory envelope.
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