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wirelessdog
join:2008-07-15
Queen Anne, MD

wirelessdog

Member

Re: UBNT 900mhz again

I think you mean to say it defeats the purpose of MIMO because it certainly does not defeat the purpose of Airmax.

Inssomniak
The Glitch
Premium Member
join:2005-04-06
Cayuga, ON

Inssomniak

Premium Member

Airmax works fine with one chain.

And yes internal+external kinda does not work well if the signal is unbalanced.

External works fine, even with Airmax.
bburley
join:2010-04-30
Cold Lake, AB

bburley

Member

Perhaps I could word that a little differently. My understanding is that lack of balanced MIMO will degrade the AirMAX capacity of the AP which will eventually impact other clients.

In a hypothetical situation with only one AP and one client that is only using one chain, the AirMAX capacity cannot exceed 50% since 100% is dependent on both chains.

Now average all of your clients with dual chain at 100% and all those with single chain at 50% (ideal conditions) and you can see that AP capacity can be improved by converting as many single chains as possible to dual chain. This effect should be worse in reality because 100% dual chain or 50% single chain is not achievable.

Before capacity saturation is reached, this condition may not have much effect, but converting single chains is always harder by the time it becomes necessary.

Based on my understanding I converted all my single chains before it was necessary to save some work later.

Is there anything in my understanding that needs adjusting?

Inssomniak
The Glitch
Premium Member
join:2005-04-06
Cayuga, ON

Inssomniak

Premium Member

A single chain client will require more time slots than a dual chain one. But it's also relevant to signals too.

So there is nothing wrong with 1x1 clients with good signal. For example I'd prefer a 900 loco with external antenna 1x1 with a great signal before I'd leave it using 2x2 with a weak signal, as that affected capacity more.

Use the priority setting too. Set lower clients to none and good ones to medium or high.

I have a lot of both mixed 1x1 and 2x2 on MIMO rockets with lots of customers and still get good throughput. I even have great performance on mixed legacy/M series airmax.

Could be just that I don't offer anything over 3 Mbps and or I don't have APs with high customer (more than 40) density. .?
bburley
join:2010-04-30
Cold Lake, AB

bburley

Member

I did lower the priority with the 1x1 clients with Yagis but then I started to think that if the AP did get congested, those clients would suffer first.

I am also using 5MHz bandwidth for improved distance and noise immunity which lowers the total AP capacity. In the past, with different and older 900 AP's, I have watched customer demand for bandwidth increase to the point of congestion. I wanted to avoid this scenario with the UBNT gear at all costs.

I am not sure where the point of congestion will be or if I will ever reach it, but it is a very competitive world and losing customers will cost more than the upgrade to Rockets and Dual-Pol Yagis.