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Re: Can anyone clarify dBic?



At 01:59 PM 6/12/2001, Scott Townley wrote:
>(Or look at it another way...if you "CP" a pair of 10dB yagis, and receive
>them on a linear antenna, the CP pair will look like 13dBic-3dB
>(polarization mismatch)=10dBi, which is the gain of one of the linear yagis).

That is not correct.  If you phase a pair of 10dBi Yagis, and transmit a 
circularly polarized signal to me using that setup, and I receive it with a 
linearly polarized antenna, I will receive only the portion of the signal 
that you transmitted from ONE of the two transmit antennas.  Yes, that one 
transmit Yagi antenna is a 10dBi antenna, but you only put half of the 
transmit power into it (because you put half into the other polarization 
which is in this case wasted).

Therefore, the result will be the same as if you had transmitted to me 
using a 7dBi Yagi.  10dBi - 3dB = 7dBi.

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