[Elecraft] P-3 background noise level interpretation

[Mike Scott]

I wonder if someone would check my understanding of interpreting broadband
noise on the P-3 display.

 

I have gone through the P-3 calibration procedure on 40M as well as
calibrating my S-Meter on the same band. 

 

Now when looking at band noise I see the tops of the yellow line at around
the -110 dBm level. If I run peak-hold, the peaks are maybe -108 dBm in the
region where the K3 is tuned (between the MKR A cursor). Without further
interpretation this would indicate S-3 or so.

 

The K3 S-Meter shows S-6 to S-7, hmmm.

 

Should I be adding 10+log(K3 bandwidth/P3 resolution) to my P-3 view to
compare with K-3 S-Meter? 

 

+/- 10 KHz span: P3 resolution = 20,000/450 = 44.4 Hz

K3 bandwidth = 2700 Hz (stock filter)

 

10*log(2700/44.4) = 17.8 dB

 

-110 dBm +17.8 dB = -92 dBm or around S-6.

 

 

AE6WA

Mike Scott

Tarzana, CA