[Elecraft] Low receiver sensitivity

[PA3GYU]

Ron,

At 04:01 11-05-05 -0400, you wrote:
>You can't get an idea of the absolute sensitivity of your K2 looking at the
>S-meter, Mike.
[SNIP]

>Look up "Receiver Sensitivity Testing" (Page 4 of the XG1 manual) and
>"Signal-to-Noise and MDS Calculations (page 5) for instructions on how to
>use the XG1 to measure receiver sensitivity.
I did, and found this procedure and example:

>A. Divide S+N by N; call the resulting ratio R.
>B. Take the base-10 logarithm of R ("log" key on most calculators).
>C. Multiply the result by 20 to obtain the S+N/N ratio at 1 microvolt, in dB.
>D. If the S+N/N is greater than 10 dB, then the MDS is approximately
>equal to the result from (C) subtracted from -107 dBm.
>
>Example: DMM readings of 1.0 Vrms (XG1 on), and 0.030 Vrms (XG1 off).
>
>A. R = 1.0/.03 = 33
>B. log(30) = 1.52
>C. 20 x 1.48 = about 30 dB (this meets the requirement for step D)
>D. MDS = -107 dBm - 30 dB = -137 dBm

Two remarks:
1. I think the second step in the example should read: "B. log(10) = 1.52".
2. I may be missing something here, but if the outcome of B) equals 1.52, 
why is "1.48" used in C)? (Not that it changes much, only 0.8 dB, but hey: 
it might confuse some people!)

Best, BartW de PA3GYU