[Elecraft] Hardware Noise Blanker on the K3

[Guy Olinger K2AV]

The hardware (IF in the NB LEVEL display) blanker is analog, and works
the same as blankers in analog receivers for decades.  But it takes
high impulse very short spikes to drive it.  An analog blanker will
always cause some degree of  "distortion", description of said
"distortion" always particular to the hearer.  Not just K3, any
classic analog blanker. The circuit is modulating the IF with what
amounts to a square wave pulse. Noteworthy in use of these is splatter
from other loud signals in the IF stage which has the blanker.

>From time to time on the lower bands, I have my hide-and-seek 13kV
power line buzz.  The IF blanker works well on this for me as long as
it's not a contest.  I drop back to the DSP blanking in a contest, but
without all the loud signals to splatter the IF blanker, the IF is a
tad better.  On the other hand, I have this AC related growl/buzz on 6
meters which the IF blanker won't touch at all.  DSP blanking t2-7 or
t3-7 gets it nicely.

The DSP blanker is the future.  It's code.  It can be worked on,
improved, and have new ideas added to it.

Oh, and one other thing, running the RF gain wide open on lowbands
with PRE on, or not using ATT when you should, is the enemy of the
blankers.  Engaging the ADC defense hardware AGC by smash-mouthing RF
gain/PRE/ATT settings mushes blanker effectiveness.

73, Guy.

On Sun, Jun 13, 2010 at 10:15 PM, juergen <plebian99 at yahoo.com> wrote:
> Hi Toby
>
> Frankly the hardware noise blanker on the K3 is mostly useless.
>
> I dont really dont even know if its "analog" in nature. I have compared it to many other analog blankers on other radios,  if it does work its barely perceptible.
>
>  I must have a faulty analog blanker. The  way people speak about how well it works i just dont see in practice. I have 2 k3's and have used my clubs K3's and they are all the same. All i seem to hear is distortion and no blanking effect.
>
>
> The DSP noise blanker on the K3 is a different story. On any of the  number 7 settings it will take care of most power line noise.  I find that   you really need  to use the 7 setting even for mild power line noise. On true analog noise blankers you could take out mild power line  noise without aggressive  settings which just cause distortion. The K3's DSp noise blanker is impressive even with all the distortion, so yes it does "work"
>
> If you  do have a radio from the past  that works in your location I would suggest you keep it. That is what I have done, I have radios here that I use on the  low bands  that beat the K3's DSP blanker and they just conventional analog  blankers. The big advantage is that I can use these blankers on low settings and still have a "decent" receiver without distortion.
>
>
> Noise blankers on radios have always been luck of the draw. I know of  several people who have changed radios for nothing more than good noise blanker performance. These days operating anywhere in big cities you really need a decent noise blanker.
>
>
> John
>
>
> --- On Sun, 6/13/10, Toby Pennington <toby423 at embarqmail.com> wrote:
>
>> From: Toby Pennington <toby423 at embarqmail.com>
>> Subject: [Elecraft] Hardware Noise Blanker on the K3
>> To: Elecraft at mailman.qth.net
>> Date: Sunday, June 13, 2010, 6:41 PM
>> Someone with power line
>> noise.......does the hardware noise blanker work very well
>> on s9 power line noise.  IF so,  is the SSB signal
>> distorted ?  DSP blankers work to some extent but
>> distort the audio.
>>
>> Toby  W4CAK
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