Which AP would you guys recomend in a high interferance area , PMP450m or PMP450i ? In my understanding the PMP450i comes with a filter but the 450m does not, so naturarely I would assume to use the 450i in this scenario and use the 450m for more populated sites ? I'm about to upgrade one of our nodes containing 3 x PMP450 with about 90 users each. So my idea were to either upgrade the site with 6 x PMP450i (60 degree Antenae) or 4 x PMP450m access points.
There are a couple considerations. It kind of depends on the spectrum availability in this location. For example, if you are using 20 MHz channels, then you could do 6 450i sectors, using a total of 60 MHz of spectrum, and cover those 270 subscribers (~45 per sector). If they are adequately spread around the site, four 450m may provide additional capacity (at ~70 per sector). If you can put these sectors into LINKPlanner, you could actually see the expected capacity for each of these products, and determine which solution would be best for your situation.
You are correct about the dynamic interference filter in 450i. This may help keep things operating in higher modulations when using 450i, but the best thing to do would be spectrum analysis at the site to see what it looks like.
Two reasons. First, the 450m does a great job with handling interference, but in a different way. Due to the beamforming capability and advanced radio design, this product isolates interference outside the Subscriber of interest (i.e. by focusing the receive antenna pattern to a very narrow beam). Secondly, the cost of having the Dynamic Interference Filtering circuitry on 7 dual polar transceivers would have been quite expensive, and we determined that it wasn't worth the added cost in light of the superior isolation techniques enabled by beamforming and beamsteering capability of the 450m.