Z-wave Range Is Quite Disappointing, What Am I Doing Wrong?

All,

I'm a bit slow in these parts, but I moved from HS2 to HS3 last month and just started setting up my Z-wave network. So far, I am very disappointed with its range. How can I improve it?

I bought a SmartStick+ and it lives in my primary PC in a telco rack in my basement. My house is all wood frame and joists (not metal) but for any Z-wave device on my main floor to get a signal from it, it has to be almost directly above the rack. Further, after being frustrated with devices not getting signals, I bought a couple of Aeon Z-wave repeaters, put them on the network, and still find that a repeater not more that 20 feet from another z-wave appliance switch isn't getting signal. What gives? Can I not expect Z-wave to go more than 10 feet through wood and drywall? I may have to rethink my Z-wave investment for another technology.

I am considering buying a USB extension cable to get my SmartStick+ closer to the basement ceiling, but I don't see how that can help with poor signals on my main floor.

Any suggestions welcome, but currently I don't have many Z-wave devices and am just experimenting with options.

Thanks!

Mike