[Elecraft] KNB2 - looking for experience with mods that made it effective

[dmb at lightstream.net]

Just a few observations regarding NR and NB, from an op at a QTH that is
at times plagued by powerline noise:

Since the KDSP2 provides Noise Reduction (NR) as opposed to Noise Blanking
(NB), the best that it can do with *any* noise is to make it easier on the
ears. It will not however drop the noise floor that may be covering up a
weak signal. I have never heard any NR on any radio that was capable of
doing that, and have never seen it have any effect on the S-meter or the
noise floor as observed on a panadapter. However, the Noise Blanker has
the potential to actually drop the noise floor (as observed on both the
S-meter and panadapter), revealing signals that would otherwise have been
completely masked.

I have both the K3 and K2, and the K3's Noise Blanker is the very best
that I've ever used on any radio, including several SDR radios, and it was
one of the primary reasons that I bought a K3 after having borrowed one
from a friend. I have had instances here where the S-meter on the K3 reads
S9 on 10 meters from powerline noise, and engaging the NB -completely-
eliminates the noise and the s-meter drops to S0 or S1, revealing signals
that were otherwise completely inaudible. Engaging the NR in this case
didn't drop the S-meter at all, and did nothing to reveal the signals that
were covered up by the powerline noise.

That said, I still find the K3's NR to be effective, but again, only to
reduce listening fatigue. Unfortunately, I've never heard NR from any
radio render a signal copyable with NR engaged, that would not be copyable
with it disengaged.

Just my $0.02 worth...

73, Dale
WA8SRA




> Stan,
>
> As I indicated, slow rise time noises (like powerline noise) will not be
> squelched by the KNB2 nor the KNB1.  They will work on fast rise time
> noise pulses like from auto ignition noise or lightning, but will not
> work on continuous noise sources like powerline noise.
>
> The KX3 (and the K3) handle the NB function differently, and in many
> instances can be effective for powerline or household appliance noise.
> For the K2, the only cure may be with the KDSP2 Noise Reduction
> algorithms.
>
> 73,
> Don W3FPR
>
> On 10/9/2013 7:20 PM, Stan AE7UT wrote:
>> Thanks Don and Ron.
>>
>> I checked the NB and it appears to be working fine.
>> I added the .001 and didn't notice any significant change in the pulsing
>> noise I'm hearing.
>>
>> I wish I could show a screen shot from my P3.  There are multiple large
>> swaths of pulsing
>> S9+ RF in this rural town.  I do live about 3 miles from a power plant
>> with
>> large electric lines
>> about a mile away.  I've never really gone out and tried to pin down the
>> noises.  Sounds like
>> a job for the KX3 on a lonely night.  In between the patches of noise
>> it's
>> VERY quiet.
>> My glass is half full!
>>
>>
>