5ghz SM's that work for lower 5ghz band, besides 450i.

We just installed a 450i 5ghz AP, the lower band is readily available but the upper band is very full. The only SM that works on the lower band is the  450i sm but its $560/ea. Can there be an update for existing 450 and 450d SM's to use the lower band? Does cambium have anything on the roadmap for this fix?

Yes, work is in progress on a new wide band SM that will be cost effective. Target is a late Q2 release, so stay tuned. 

If Cambium would like some field testing done, I would be happy to be one of those guys!