Hello jthienel,
Ensure that both gain and atten are non-negative. Any negative number will cause the device to select the gain/atten automatically.
If you are interested, setting the gain/atten to automatic (-1) the default condition, the reference level set in saSetLevel() controls the gain/atten automatically optimizing for signals at or near the reference level. For example, if you know your input signal is -20dBm, setting the reference level to -15 will optimize the device for your measurement. You can get much more consistent results with this method. Maximum sensitivity is achieved with a reference level of -50 or less.
Let me know if you have additional questions.
Regards,
Andrew
