[MLB-WIRELESS] Antenna Overlap

[Fenn Bailey]

The easiest way to think of it (and I hope I'm right with this), is that
antenna gain is bi-directional.
 
eg: It will boost the power of signal you are transmitting out of it AND
the power of the signal coming into it by the same amount.
 
Due to that (in the situation you describe), your directional not only
beams a focused RF beam to your omni, but also focuses the 'faint'
signal from the omni in exactly the same way.
 
There has been some talk of some cisco wireless devices that can bind
one antenna to send and the other to receive (NOT diversity), so you
could put the maximum legal antenna on the send side (to acheive your 4W
EIRP) and a HUMUNGOUS dish on the receive side (think radio-telescope
size), and get really long distances.
 
How practical this is, I don't know, but it would be fun to try :)
 
    Fenn.

-----Original Message-----
From: owner-melbwireless at wireless.org.au
[mailto:owner-melbwireless at wireless.org.au] On Behalf Of Jason Brice
Sent: Wednesday, 15 January 2003 4:36 PM
To: melbwireless at wireless.org.au
Subject: [MLB-WIRELESS] Antenna Overlap


One of the things im not really clear on with respect to Antennas and
the whole RF thing;
 
If i have a low gain omni with an effective range of say... 1km and i
have a high gain dish (enough to include the omni in the signal range)
some 15km away pointed at the omni, i understand that the omni can pick
up the radiated signal from the dish, but is the dish able to pick up
signal from the omni at that range? and if so why is that? :)
 
Feel free to post an RTFM link if this has been asked and answered. Im
new to the whole RF side of things.
 
Thanks,
 

________________________
jason brice
senior network engineer
kiandra system solutions
level 9, 455 bourke st melbourne vic 3000
(t) +61 3 9600 1639
(f) +61 3 9600 1656

 

 

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