[Elecraft] K3 S meter

[Bill W4ZV]

Barry Simpson wrote:
> 
> It is a fact that the band noise is not for example  S5 - and my FT1000MP
> MKV and TS2000 read S0 or S1 in the same situation.
> 

This is because most rigs' meters are inaccurate and indicate ~3 dB per
S-unit below S9.  Identical "S1" noise on another rig would be 24 dB (8
units [S9-S1] times 3 dB per unit) lower than 50 uV (S9), and indicate S5 on
the K3 (4 units [S9-S5] times 6 dB per unit).  

Below is a typical S-meter (FT-1000), and you can see that "S1" on it is
actually closer to a real S4:
(from http://www.n6rk.com click on "FT-1000 S-meter calibration"

Actual  Equivalent*
1	   3.8	
2	   4.2	
3	   4.3	
4	   4.7	
5	   5.2	
6	   5.7	
7	   6.3	
8	   7.3	
9	   8.3

* Equivalent means S9 for 50 uV and 6 dB per S-unit, according to the
following table on the same site as above:
http://www.n6rk.com  click on "Definition of S-unit"  

Another problem is that most rigs' S-meter readings will change if you are
use a Preamp or Attenuator.  In the K3's ABSolute S-meter mode, the reading
will not change with Preamp or Attenuator settings, since it is correctly
reporting the signal at the input terminals (which of course does not change
with the internal Preamp or Attenuator setting).

The K3 meter is probably one of the more accurate S-meters available,
especially below S9.

73,  Bill  

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