[Elecraft] More data on K3 Receiver S meter calibration

[Don Wilhelm]

Mike,

The only 2 things in the receive path that differ substantially from 
band to band is the Low Pass Filter and the Bandpass Filter.  Unless the 
"component" you refer to is a part of those filters, it is unlikely to 
be a component problem.
It would seem that you have a problem with one or the other. Further 
testing with an RF Probe or an oscilloscope and a strong signal 
generator may reveal which one.  The XG3 may have enough output for 
investigation with a 'scope, but I doubt it is strong enough to use an 
RF Probe.

Yes, you may wish to take the easy path and have Elecraft check and 
align it - contact K3support at elecarft.com if you wish to start that process.

73,
Don W3FPR

On 9/11/2014 1:37 PM, Mike Sullivan wrote:
> I got one response from Don W3FPR who indicated I should try S-Meter Config MD: to ABS "which causes the S-Meter reading to stay fairly constant but require SMTR OF and SC to be re-aligned" and to "find a happy medium for the setting".
>
> The K3 internal Tuner was bypassed.
>
> I did that and have prepared the following table of  observed S meter values (utilizing the XG3):
>
>
> Band    -73 dBm      -33 dBm
> 160           S9                S40
>     80          S9                S40
>     40          S9                S45
>     30          S9                S40
>     20          S4                S10
>     17          S9                S40
>     15          S9                S40
>     12          S9                S40
>     10          S9                S40
>
> I did double check the XG3 with the Rigol Spectrum Analyzer and it was dead on.
>
> The obvious question is why is the 20 meter results so different from the other bands?  I am enough of a purist to send the K3 back for a re-alignment,  but could an incorrect component been assembled on the receiver board?
>
>