Questions about SR71-5 for PtP backhaul link

[miami3o5]

We currently have a 2 mile Tranzeo FDD 5Ghz backhaul link pushing through about 22 Mbps. We would like to pull more bandwidth since we have about 100Mbps available at the Data Center.

I've been looking at the SR71-5 radio module and Im trying to understand.

I need to put the SR71-5 into the LiteStation SR71..correct?

then I would need to put this inside an outdoor enclosure, add a pigtail, and go to an external antenna?

My main question is... doesnt MIMO need mulitple antennas? does the SR71-5 have multiple antenna plugs or do I just use 1 antenna for a point to point link?

Will I get significant more bandwidth than my current Tranzeo FDD link's 22Mbps?

Thanks in advance.

[MRojas]

The SR71-A card does require at least two antennas for MIMO 2x2 operation.

I recently installed a set as backhaul in a 3x3 setup that's pushing 92 Mbps actual TCP throughput at about 1/2 mile. Although I didn't follow all the rules about antenna spacing, I'm pleased with the results. I may or may not move the antennas... if it ain't broke, don't fix it, right?

For my 3x3 setup I used an old Trango dual-polarity reflector and a 1' 5.8 GHz dish w/ radome.

You will have to put them in an outdoor enclosure and use 3 N-female bulkhead connectors with MMCX connectors to connect to the SR71-A.

~$700 for a full link that does 92 Mbps is not a bad deal.

[MRojas]

If I'm not mistaken, MIMO is not full-duplex, so the 92 Mbps is the total throughput in one direction.

Although you can manage how much bandwidth is used for the upstream and downstream many ways, I found in my testing that the radios split it up. So, if you're using up 60 Mbps on the downstream, you'll have 30 Mbps for the upstream. At least that's what I observed when I ran throughput tests with both the TX and RX at the same time.

By the way, I used the Mikrotik bandwidth tool and tested from my laptop to a router on the other side. NOT to the radio. For many obvious reasons, you do not want to test for througput to a radio, but THROUGH a radio.

[wirelessrudy]

ANY radio link is simplex. A radio can do only one thing, either send or ´listen´ (=receive).
If we talk about ´duplex´ or ´semi-duplex´ it just means we actually have two paralleled radio links.

´Full duplex´ usually means we use 2 x 2 radio with 2 links between them each on its own freq. Both sides can send, or both can receive at the same time.
´Semi-duplex´ means that the switching between ´send´ mode and ´receive´ mode of the radio goes that fast that it looks like we have two radios on either end. This is what we do in Wifi (and Wimax, cellular, satellite etc. etc. etc.)

As an result, it also means that theoretically the speed of the radio link in both directions is always the same. If there is a difference between one way direction and the other in throughput then this is a result of other factors.
Think on processing units on each end, transmitting power versus sensitivity in listening, rate limitations etc.