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Old March 6th 09, 07:23 PM posted to rec.radio.amateur.antenna
Owen Duffy Owen Duffy is offline
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First recorded activity by RadioBanter: Dec 2006
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Default Definition of antenna receive gain?

Daniel wrote in news:0ba6e6da-f856-4e7b-a272-
:

Hello,

Let's say I have a transmitter with output power T dBm using an
antenna with A dBi. Then we have a receiver, with gain B on the
antenna. How does this affect the received signal strength? I guess
the field strength at a point (in the transmitter antenna lobe) would
be something like T+A-PL where PL is the path loss at the point.


Daniel,

Look up the Friis Transmission equation on Google.

Here is a little application for solving the Friis Transmission equation:
http://www.vk1od.net/software/fsc/ .

Another concept that is important is reciprocity, but understand that
limit of the scope of the concept (eg it doesn't capture differences in
impedance mismatch from tx to rx).

Owen

But what does the receiver get when it uses an antenna? Is there a
notion of reciever gain of an antenna? In my mind I can't see that
anything else than antenna area would be relevant. I mean, a reciever
antenna shouldn't be able to suck in radio waves from the sides...
Can anyone sort this out?

Regards,
Daniel