Exam 200-355 topic 1 question 403 discussion

Here some notes to resolve, 1. Required EIRP is 200 mw which is 1*10*10*2 or 0 dbm + 10 db + 10 db + 3 db. So 200 mW = 23 dbm 2. Antenna gain is 21 dbi 3. Since total EIRP is the product of conducted power plus antena gain and the latter is a given, then power fed to the antenna = 23 dbm minus 21 db = 2 dbm 4. So in order to achieve a 23 dbm EIRP, we need to feed 2 dbm to the antenna. 5. Now we need to compensate for the loss introduced by the cable which is 2 mW or 0 dbm + 3 db. so configured Tx power = 2 dbm + 3 db = 5 dbm 6. From all of the above we arrive at the conclusion that in order to achieve a 23 dbm (200 mW) EIRP in the given scenario, we would need to configure the radio with a 5 dbm (3.16 mW) Tx power setting.