[Elecraft] [K2] Filters attenuation

[Don Wilhelm]

  Mike,

Your results are not all that abnormal.  Most do not begin to encounter 
attenuation until less than 400 Hz, so yours is slightly worse off than 
normal in that regard - but then I usually consider 2 dB to be within 
measurement error range.
However, I was concerned about those who said they had significant 
attenuation at 700 Hz.

Even though there is attenuation at the narrow filter settings, the 
filters are still quite usable for combating QRM.  On the lower bands, 
the band-noise is typically high enough that adding more gain is not 
beneficial unless your antenna is inefficient, but on the higher bands, 
running with the preamp on will more than make up for the few dB loss of 
the narrow filter.  In other words, while this is an interesting topic 
for those of us with measuring tools (signal generator and Spectrogram), 
it is not likely to make a huge difference in actual operating.

73,
Don W3FPR

On 11/5/2010 1:29 PM, Mike Harris wrote:
>
> Measured using Spectrogram ref level for audio peak -90dB.  The
> sound card in my PC isn't particularly good and this low level
> eliminates displayed audio harmonics.
>
> Filter:
> 1000Hz -90 (ref)
> 700Hz -90
> 400Hz -92
> 200Hz - 94
>
> FWIW.
>
> Regards,
>
> Mike VP8NO
>