@David-TP 

thanks for your reply. The specifications listed for this produce suggest somewhat less than 10m. If you take the coverage and calculate the radius for the specified coverage area it comes out at just a little over 8m radius from memory.

Hence my question.

it would be good if the specs not only stated coverage area but mentioned a radius or straight line clear air coverage.

  @lad337 To flesh out my requirement, I have an outdoor location with power and could arrange a wired connection either vie network over power line or by running a network cable. The 3 existing decos are each in their own building. The 20m radius would mean overlapping coverage. 
 

there is also a TP-link Archer MR600 in the mix.

The objective is to bring network to another building for IOT devices located there.

  @David-TP from what I have read through these community pages the omada commercial unit won't form part of the mesh, funnily enough I was looking at them earlier today.

The area concerned is clear air with no line of sight obstructions. It is a shame that the specifications talk in terms of area coverage, the straight line data is also very useful, coverage area is virtually useless.