[Elecraft] K2 filter attenuation

[Eric Manning]

My K2, aligned per Tom's Spectrogram procedure, passes the "Don Brown test" FB.

There is no pitch shift as I move to narrower filters, but there IS 
some attenuation of signal strength when I go to Filter 4 [100 Hz]. 
Not a lot, msybe 1 S unit.

I think this is perfectly normal, as we're getting the narrow 
passband by snuggling the signal right up against the edge of the 
filter's passband. And, despite what the pretty picture in the manual 
shows, those crystal filter passbands are NOT perfectly rectangular. 
No real filter has a rectangular passband -- it is a figment of the 
filter theorist's imagination. The edges are not vertical -- they 
slope inwards towards the centre.

  So, we must lose  signal strength as we get closer to the edge of 
the passband.

[No, I don't want to talk about complex impedances on transmission 
lines. Ever. =)   ]
-- 
Eric Manning   VA7DZ VE3DPV
K2 #2561 "Pauline"

If God intended you to use SSB, He wouldn't have given you a fist. Or 
two lungs.