Part of the idea between spatial diversity is creating a second path that won't 
have the same obstructions.  Take this out of the idea of the MIMO technology 
and simply go with the idea that possibly one path will have different or less 
tree blockage/absorption or possibly that reflections are more advantageous 
than a single path.  I did this in an RV park but didn’t have anything to 
compare it to so did it work better, I'm not sure.   

Rory
-----Original Message-----
From: Af [mailto:[email protected]] On Behalf Of Adam Moffett
Sent: Wednesday, August 26, 2015 8:20 AM
To: [email protected]
Subject: [AFMUG] Spacial Diversity - helps how much?

There are a couple of products out there selling 4x4 MIMO (Telrad is one, but 
there are others).

In Telrad's case, two of the chains have a time offset from the other two, so 
you get two chains on each of two polarities.  Their default antenna is a 
single sector antenna with 4 N-connectors on it, so there's no significant 
spacial diversity.  In the past it's been suggested that we use two dual pol 
sector antennas and space them 3 feet apart to get spacial diversity.

When I asked why they do the single antenna, a source at Telrad told me that 
spacial diversity "only helps a little".  The party selling us the two panels 
considers it to add 6db when they run coverage projections.  
I suspect any gain from spacial diversity is going to depend on a lot of 
circumstances and I doubt it could be as simple as adding 6db.

I'm wondering if anyone here has any opinions on the topic?  Maybe even facts :)

(I'm sort of eyeballing a certain guy in Utah who designs antennas and isn't 
trying to sell me anything.)

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