Q: airdrop on my mac doesn't recognize any devices

I have mid year 2009 white Macbook (running Yosemite 10.10.5)

Air Drop screen is blank - doesn't show any of my devices

I can Airdrop from my Iphone5 and Ipad (both running IOS10) to other Iphone users with no trouble

Re: System Preferences, I have checked and re-checked Security, Firewall, Bluetooth and Sharing settings

Any other suggestions?