30 Mbps Canopy

Hi,
Has anyone encounter problem with the 30Mbps during Harmathan? We have a link with 10Mbps, 20Mbos and 30Mbps. And recently when harmathan certain in our region, only the 30Mbps became unstable. Also some of the could not stand interference; I am surprise only 30Mbps units on my network behave like that.
Need assistance.

Thanks

Bruno From Ghana- West Africa