[Elecraft] K3 - FW 2.20 audio levels

Fred Jensen k6dgw at foothill.net
Thu Jul 24 19:29:04 EDT 2008


Just installed 2.20 ... please disregard all of my previous comments 
regarding low audio levels for us deaf guys.  I got the AGC fairly flat, 
found out higher thresholds seem to raise the point where AGC starts, 
thus things got markedly louder.  After this I ran the AF gain at about 
11 o'clock.  Tried AF LO, gain is about 1 o'clock but no distortion at 
all.  As far as Audio Levels go, I'm a happy ham ... well I'm a pretty 
happy ham in a lot of other respects too.

I was messing around with the FIR/IIR thing and found that, listening to 
W1AW on 14047.5, narrowing the DSP bandwidth from 500 Hz to 150 Hz 
produces nearly no change in audio level.  Going to 100 Hz, either FIR 
or IIR didn't matter, the audio level drops dramatically, and stays 
there at 50 Hz too.  I'm pretty sure I've missed a detail here.  I don't 
run at 100 Hz hardly at all so it isn't really going to affect me, just 
curious.

Regarding ringing of IIR filters, I understand the math [math and engr 
degrees], but honestly, I don't hear much difference at 100 Hz BW 
between the finite and the infinite [never thought I'd find a way to use 
them in the same sentence].  W1AW sounds about the same, and there is 
almost no ringing.  It sounds a little "peaked" to me, but then again, 
without my hearing aids, everything sounds "peaked" at about 600 Hz.

Hope to hear lots of Elecrafters in the Flight of the Bumblebees this 
Sunday.  I'm a "Bee", I'll be on with my K2, BuddiPole 20m vertical GP, 
and solar charged gel cell.  I may have one of W6MMA's yagi's and if so 
I should be 5NN for you :-)

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2008 Cal QSO Party  4-5 Oct 08
- www.cqp.org



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