[westbywest]

Indeed the 24GHz and 60GHz gear has its unique rain fade issues not shared by 5.8GHz. Increased atmospheric attenuation of higher bands is the general trade-off for higher throughput and more compact physical isolation requirements. UBNT 24GHz gear is being using for ~10km links, but looks like the ~5km is the preferred limit. My original comment would have been better written to stress need to prove out the signal path over all intended bands, e.g. primary link over (near) optical and fallback over whatever RF band proves viable.