Maybe a boot loader issue?

My sketches on both the Arduino and Nano sides compile ok using the nRF24L01. The respective sketches upload properly as long as my Mac is attached to the respect boards. When I try to use external power i.e. battery I get errors saying the board in not available. After tinkering with it I find as soon as I incorporate radio.begin() the sketches go south. Wiring is ok and #includes are ok. Has anyone else had a similar problem?

Need a wiring diagram ; some of these radios require quite high peak currents , so you need a decent power supply and possible a capacitor .

GregWalter:
My sketches on both the Arduino and Nano sides compile ok using the nRF24L01. The respective sketches upload properly as long as my Mac is attached to the respect boards. When I try to use external power i.e. battery I get errors saying the board in not available. After tinkering with it I find as soon as I incorporate radio.begin() the sketches go south. Wiring is ok and #includes are ok. Has anyone else had a similar problem?

Maybe I'm missing something, but without the boards actually connected to the computer they definitely won't be available to the IDE.