[Elecraft] P3 Questions concerning measurement

[Fred Atchley]

Hi all. While waiting for the P3 I have a few questions on setup and
measurement. Since I have never used LP pan or similar devices I'll need
some Elmering. Specifically there are two capabilities listed in the
Elecraft P3 page that I need help on:

1.  Adjustable reference level and amplitude range scaling 

2.  User calibration of the display to show absolute signal level in dBm 

Number 1 suggests two parts. It has an "adjustable reference level".
Question: WRT what reference: 0 dBm, the bottom of the spectrum display
baseline or some particular value? The other part adds "amplitude range
scaling". Is this a separate function or is part 2 the conclusion of the
process? 

My second question concerns the use of the absolute signal level in dBm. If
I am assisting a Ham friend in adjusting his signal, will this capability
allow me to evaluate such things as his BW and compression? I know that I
can do that now by ear but will the P3 give me a visual clue WRT onset of
changes over-the-air? I have an HP Spectrum Analyzer that I have used to
check my own K3 on- the-bench. So the phrase "over-the-air" is the big
question.  

These questions do not pertain to the main reason I am looking forward to
the P3 (I.e. operating) but rather to the "other" useful possibilities. I
appreciate the group's Elmering.

73, Fred, AE6IC, K3 #2241, P3 #?