Killing noise, continued

• I started looking into this sampling noise and found out it was worse with an xbee pro than a regular xbee.
• I tried to protect my Vcc from fluctuations by adding more capacitors, but that didn't help.
• Eventually, I found it happened more when the batteries weren't full, and that the voltage out of the regulator was dipping below 3.1V instead of 3.3V.
• Then I realized that the diode that protects the input of my voltage regulator dropped about 0.7V and was enough to turn the 5V out of my batteries into 4.3V, which was too marginal for the voltage regulator under load.
• Solution was simple, short circuit the diode.