[Elecraft] P3 amplitude calibration

[Alan Bloom]

Actually, you don't need to calibrate the P3 at different levels.  The
ADC is linear within a tiny fraction of a dB over its whole range, so
once you calibrate at one level, all levels should be accurate.

But you bring up a good point about needing a different signal source
for each band.  I guess I should include a "global" calibration that
applies to any bands that haven't been calibrated.

Alan N1AL


On Mon, 2010-08-30 at 13:36 -0700, Mike Scott wrote:
> Given Alan's plans, I detect a need for an XG3 now that he wants to make the
> P3 amplitude calibration per band.
> 
>  
> 
> The XG3 could be ten band 160 through 6M accurate 50 uV and 1uV source. 
> Actually I might want something other than 1 uV as that is an awkward value
> between S3 and S2.
> 
>  
> 
> So a 10-band source with -73 dBm and -103 dBm outputs might be better
> because -103 dBm would be S-4 for those who like 6dB per S-unit and S-3 for
> those who want  5dB per S-unit.
> 
>  
> 
> AE6WA
> 
> Mike Scott
> 
> Tarzana, CA
> 
>  
> 
> ----------------------------------------------------------------------------
> -------------------
> 
> Alan N1AL said: 
> 
> On my list of features to add is amplitude calibration, similar to the
> 
> S-meter calibration in the K3.  I plan to make it per-band to account
> 
> for variations in the K3 RF chain and to separately measure the gain of
> 
> the K3's preamp and the attenuator.  This level of accuracy isn't really
> 
> needed for normal operation of a radio, but as an ex-Agilent/HP engineer
> 
> I'm kind of a perfectionist when it comes to measurement accuracy.  :=)
> 
>  
> 
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