A:Answer I had one node downstairs and a second node on the second floor and they saw and talked with each other fine. The signal upstairs fluctuated between 4 and 5 bars with the second node installed, which surprised me. I expected 5 bars as the node was 3-4 feet away from the smartphone I was using. That phone showed a solid 4 bars for the original node before I connected the second one.
Check for interference where the first node is installed. Make sure it is "out in the open" as Linksys recommends, rather than buried behind other things. The app also has an advanced setting (sorry, I stumbled on it while experimenting and do not remember where it is) that will examine the network and adjust the channels the nodes are using, if needed, to optimize the signal. Personally, I was surprised that was necessary as I presumed te setup process would have already done that.