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From:
Date: 04 Apr 2003
Time: 05:21:02
Remote Name: 20.138.254.2
Hakon - I agree with your idea and the efficiency is equal to the ratio of the lossless bandwidth to the actual bandwidth because it is the same ratio as the radiation resistance to the total resistance. The lossless bandwidth equals F0/Q which is equal to F0.Rrad/X, and the actual bandwidth equals F0(Rrad+Rloss)/X. So the efficiency, which equals Rrad/(Rrad+Rloss), equals the lossless bandwidth divided by the actual bandwidth. That is a good approximation provided Q is 10 or more, as it often is for small antennas. It is a good way of estimating efficiency when the loss resistance cannot be measured directly . . . 73s Alan