Mimo antenna test (practical example)

[swwifty]

Since I've been doing a million of different tests, thought I'd do a simple test with and without the diversity (or secondary) antenna that is used for mimo. I've been reading and learning a lot about it, and doing this test showed me a few things.

This was done actually inside my house, with the antennas (these antennas were used in this test: https://thewirelesshaven.com/shop/antennas/700-27 ... l-antenna/) facing out a window pointing directly at the known tower my service connects to. (I only did this because it was raining/wet outside)

Signal strength with both antennas attached:

Screen Shot 2018-10-26 at 12.43.24 PM.png

Speed test with both antennas still attached:

both bands both antennas.png

Signal strength with diversity antenna detached (in this case the secondary, RxD in this screenshot):

single antenna.png

Speed test with secondary antenna detached:

single antenna speed test.png

A couple of observations:

1. I did the speed test as quickly as possible back to back to try to reduce variables at all, and you can see in this particular test, I lost about 40% of my download speed. I've seen this vary a good bit, with other tests I did, so don't take this as a hard or fast rule of how much bandwith you will lose if you don't use a diversity antenna (spoiler alert: I always recommend using one.)

2. Upload speed is unaffected because there is no mimo in uplink, and hence the secondary antenna is not used.

[swwifty]

Thought I'd share an interesting article on antenna spacing as it relates to MIMO performance:

http://airccse.org/journal/jwmn/1212wmn13.pdf