Apple sucks at developing Airdrop, it is a big piece of sss...
That said, try the following:
Disconnect any device that uses bluetooth from the Mac (if you use a trackpad, take out the battery). Then turn off the Wifi and Bluetooth in your Mac.
On your iPhone, scroll up the control panel, and disable both Wifi and Bluetooth too.
Now, press Airdrop on your iPhone, it will ask if you want to keep it off, contacts only, and everyone. Select everyone. It will then turn on Wifi and Bluetooth automatically as you need both on to use airdrop.
Open Finder in your Mac, select airdrop and do the same thing.. turn it on with Everyone, and it will automatically turn on Wifi and Bluetooth.
After 2-3 seconds your iPhone should pop up in the centre of the Finder window.
Hope it helps!