I was one of the people who wasn't quite happy with K3 audio.
Perhaps my experience will help others.
I worked with Wayne and he noticed something in my audio recordings and made
some suggestions. There are a lot of combinations of AGC settings that I had
worked through but the background noise in my high-noise environment always
left me fatigued. Note this is not hiss just loud band noise as presented to
my ears, the narrower the filter the more tiring the noise. (Think of a
windstorm outside whistling through the trees the narrower the filter the
more band-limited the noise and the more whistle-like.)
Well now, it seems Wayne asked me where my Pitch setting was. I hadn't
thought about moving it before he asked.
I now set Pitch to 420 and the color of the background noise has changed,
significantly. I have been sitting here for a couple of hours working on my
computer with the K3 tuned to just noise and it seems like I am listening to
a different receiver. High noise environments are a major bummer but I am
finding ways to cope. This Pitch effect is probably psychological but higher
pitched whistling through the trees left me significantly more tired.
Changing Pitch has had a major effect on these tired ears.
Other than the Pitch, here are the settings I find the best for my
environment:
AGC DCY = Soft
AGC Hold = 0.3
AGC PLS = Off
AGC SLP = 8
AGC THR = 2
AGC-F = 80
FGC-S = 20 (I normally operate in slow now)
Comments:
There have been many comments about AGC induced IMD in pileups. Large noise
backgrounds may act like its' own pileup. I am not an expert here but noise
can cause AGC gain fluctuations just like one signal in a pileup causing
gain fluctuations that the rest of the signals mix with. The larger the
fluctuations and the faster the fluctuations the more chances there are for
creating mixing products in the audio range. Operating with AGC off and
riding the RF gain control is the most pleasing audio solution but going to
soft decay and slow AGC makes sense and helps a lot.
AGC THR=2 causes the AGC to engage sooner, in effect this sounds to the ear
like turning down the RF gain reducing background noise. Reduced RF gain
always helps when the signal is strong enough. This may actually not help
the IMD situation, don't really know.
AGC SLP = 8 doesn't quite sound as good as 12 but this is a tradeoff to be
able to distinguish weak from strong signals. I operate in diversity mode
most of the time with a vertical and a dipole. I like to be able to hear
which path is producing the stronger signal.
AGC-F = 80 reduces the decay rate after noise events. This then is a
compromise between stock 120 dB per second decay and the slow AGC decay rate
of 20 dB per second. Think of this now as AGC-Medium, this is not a major
effect.
Thanks for taking the time Wayne.
Mike Scott - AE6WA
Tarzana, CA (DM04 / near LA)
NAQCC 3535
K3-100 #508 / KX1 #1311
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