Is the Nano a good PS for nRF24L01+?

[Zeph]

@Fabien posted something of interst to me a week ago:

With UNO I have more lost packets without extra capacitor. I think 3.3V output is not enough good. With Arduino Nano, it's ok

So far I've not tried using the Nano's 3.3v supply for the nRF24L01+; as I understand it, the 3.3v supply was a side effect of the FTDI USB to serial chip, and I wasn't sure of its quality.

But if it works, I might use the Nano for some nodes. In particular where I need to run the uC at 5V for sensors or pixel LEDs, but the radio at 3.3v, it would save some space and wiring.

Do people have good experiences running the non-amplified nRF from the Nano's 3.3v supply? Has it worked with nano clones (I think some have replaced the FTDI with a CH340 chip)?

[Zeph]

Hm, I just found a reference regarding the CH340 and 3.3v. From http://www.minikits.com.au/nano-v3.0b

The Arduino Nano can be powered via the Mini-B USB connection,  6-20V unregulated
external power supply (pin 30), or 5V regulated external power  supply (pin 27). The 
power source is automatically selected to the highest voltage source.

The CH340G chip on the Nano is only powered if the board is being powered  over USB. As a result,
when running on external (non-USB) power, the 3.3V output  (which is supplied by the CH340 chip)
is not available and the RX and TX LEDs  will flicker if digital pins 0 or 1 are high.

My question about using the 3.3v supply from the Nano for the nRF came from two use cases:
Running with a 5v USB power supply sounds OK. But I was also thinking of running from a 12V supply in a case where 12V is used for relays and lights anyway. I was thinking to use the onboard 5V regulator for the Nano's uC, and the 3.3v supply for the radio. The quote sounds like the latter would not work - unless perhaps I bridged the 5V from the uC regulator to the USB 5v pin to activate the CH340 ? (Some more power, perhaps interference if I wanted to use the uC RX pin).

Any knowledge or experience to share?

One aside: Sometimes a regulator is spec'd up to 12v and sometimes a 12v supply is a little high. My thought was to insert a diode in line to drop a volt or so; this should give more margin, and also at least slightly reduce how much of the voltage/power has to be dropped & dissipated inside the linear regulator. As a side effect, it might help with accidental reversal of voltage. This is also my answer to someone who wanted to run an unregulated ardu pro mini off 4xAA alkaline.