[MLB-WIRELESS] passive repeater

[Roger Venning]

Passive repeaters in RF terms are two antenna connected via purely passive
(ie. non-active) components, e.g. waveguide or coax.

The are not a myth. For example:
- http://www.itu.int/itunews/issue/2001/06/dev.html in a ground station
- http://www19.addr.com/~longline/places-routes/Thurmont_repeater/index.html

I heard two engineers talk just today about I think Channel 7 using a
passive repeater in South Melbourne today - two huge 3m parabolic antennas
connected via waveguide, aimed 90 degrees apart.

*HOWEVER* at 2.4GHz within the power limitations of the unlicensed band they
ARE next to useless. Especially with low gain antenna like pringles. The
maths doesn't add up, as forwarded by evilbunny. The work we you can afford
to waste a LOT of power, or where the repeater is close to one end. They are
restricted to limited applications, you must do the math first to work out
whether you can expect results. Remember that as they are not powered, much
higher gain antenna can be used (ie. BIG dishes).

Roger.

--
Roger Venning  \ "Research is what I'm doing when I don't
Melbourne, Aust \  know what I'm doing." Werner von Braun.


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