Spatial Diversity Dish Mounting

On a spatial diversity setup, can your diversity dishes have some horizontal deviation, or do they need to maintain the same vertical center line? Thank you

The spatial diversity dishes do not need to be exactly on the same vertical centerline, but they do need to be installed on the same structure. I’ve worked on diveristy systems on large self support towers where the diveristy dish was 15 ft off the centerline of the upper dish. The vertical spacing is the critical dimension - the purpose of the spatial diversity is to make up for any temporary anomoly on the path between the upper antennae causing fading. The same vertical centerline is ideal if you can achieve it.

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Appreciate it. Did you see big variations from projected RSL if you went horizontal any distance?

No, the RSSI reported by the receiver is generated from the upper dishes. The lower dish only operates as a receiver in diversity mode, and the output is summed between the 2 receivers. If you don’t have the diversity setup correct, as far as the antenna installations are concerned, the only way you would really know how it’s working is the operation during a fade - the link may not be as robust as you need.

Ok, would you not see it also during alignment since it’s not technically part of receiver 1? Seems like any horizontal variation from the main would cause some reduction in RSSI, no?

I don’t think so. If the top antennas are centered on the main lobe, the difference in the angle to the diversity antenna will be well within the beamwidth of the transmitting antenna.