[Elecraft] Auto Notch Revisited.

[Tim Tucker]

I agree with the majority of your assessment.  I also brought up the Auto
notch issue several years ago and haven't seen much, if any improvement.
 As a result, I nearly always just use manual notch.  I also have the same
complaint with the way the NR in the K3 works.  The KX3 implementation is
far superior, IMO.  I've actually considered coupling an AF DSP speaker
product from West Mountain Radio to the K3 to overcome the K3 autonotch and
NR limitations.  I've used one of their speakers mobile for many years
coupled with my IC-7000 with a lot of success.


On Thu, Jul 31, 2014 at 2:01 PM, wa9fvp <repair at willcoele.com> wrote:

> It's been 2 years since there were complaints on this forum about the K3
> auto-notch.  Apparently it was never fixed.
>
> The other day I was working a Ham in Tel Aviv when a carrier came on and
> covered his signal.  The Auto notch worked well but the guys voice was very
> distorted.  To me that's unacceptable.
>
> This year at the Dayton Hamvention I talked to someone from Elecraft about
> the DSP problems and he agreed that the auto notch needs some improvement.
> I think he was a the product manager.
>
> Back in the early 90's I worked with another Engineer on a project we
> called
> "The Hamblaster". I published two articles in QEX (October 1991 and January
> 1992). We developed a PC based sound card that connects to the receiver's
> audio and performed, among other things,  an auto-notch and noise reduction
> (NR).  In our DSP software, the auto-notch was generated by summing the
> inverted NR output to the input signal.  Whether it's a noise reduction or
> an auto-notch we still used a software algorithm called the LMS (Least
> Means
> Square).
>
> Most Ham transceiver use the same LMS algorithm and I never heard distorted
> audio when the notch was engaged.  That's especially true with Yaesu, Icom
> or Kenwood. I'm not sure about the other American brands but I bet they are
> OK as well.
>
> My second complaint is the K3's NR control.  Most other manufacturers have
> an analog like control that simply changes the NR level.  I don't
> understand
> the logic of having several steps from F1-1 to F4-4 and F5-1 (mixed) to
> F8-4
> (mixed).  I would rather have two separate settings.  F0 to F9 for the
> level
> and if you want a to fiddle with the delay, D0 to D9 in the main menu.  I
> think the level control on other radios is simply a mix of the input signal
> with the NR output and is similar to the K3's mF5-1 to mF8-4
>
> To me it sounds as if there's a dynamic range problem on the K3 whereby the
> numbers in the math are over-ranging when the notch is engaged and is
> causing a "flat-topping" in the audio signal.  But that's just a guess!
>
> I hope someone at Elecraft reads this and gets the ball rolling to fix the
> problem!
>
> Jack WA9FVP
> Willco Electronics
> repair at willcoele.com
>
>
>
>
> -----
> Jack WA9FVP
>
> Sent from my TRS-80 :-)
> --
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