Question about KNB2 Noise Blanker

[Marinos]

I do have to agree with the comments for the NB in the K2. I do have power
line noise in my QTH which seems to be unaffected by the K2NB, especially
when it falls below an S9 level, which sometimes can be the limiting factor
in completing a QSO.
The majority of the time I have to engage the Preamp in order for the K2NB
to start detecting the pulses, and at that level of Rx gain, the receiver
may become overloaded by nearby strong signals if present.

>From all other rigs that have come here at different times, only the NB in a
TT Corsair 560 used to behave in a similar way.
In order of NB function, the best rigs I have tried so far are TS830, 930
and Drake TR7.

For a receiver of the K2 caliber, I believe, it is worth every penny and
construction effort, even if it means incorporating a "pre-made" surface
mount module for the NB in order to improve on the NB area which seems to be
suboptimal.
For example an "expensive and/or difficult to build" but optimized NB module
will be FAR more desirable and effective feature in a real world Rx
performance improvement rather than a similar DSP module that is already
available from Elecraft.

These are my $.02 opinion about the NB, which may be the only area that
needs some improvement in a radio that has no equal in the market today. And
can definitely make a difference for people wanting to have a K2 as their
only/main rig in a urban QTH....as most of us live.

73,
Marinos, ki4gin


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[Thom LaCosta]

On Sun, 2 Jan 2005, Marinos Markomanolakis, M.D. wrote:

> For example an "expensive and/or difficult to build" but optimized NB module
> will be FAR more desirable and effective feature in a real world Rx
> performance improvement rather than a similar DSP module that is already
> available from Elecraft.
>
> These are my $.02 opinion about the NB, which may be the only area that needs
> some improvement in a radio that has no equal in the market today. And can
> definitely make a difference for people wanting to have a K2 as their
> only/main rig in a urban QTH....as most of us live.

Couldn't agree more...I live in a very old part of the city here...surrounded by
industrial users of power, a leaking power grid and a utility that doesn't care.

Since I've gotten back on the air the K2 sits on the desk, glaring at me because
it's virtually useless with S9+ QRN.

If I'm lucky, I can operate between 2 AM and 6 AM, as long as I turn off the oil
burner since it too acts like an arc gap.

Thom

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[Don Nesbitt]

Hi Thom.  Not to prolong the agony (I think that Wayne has already put this
on the "list" - hope it moves up to a high priority), but I have the same
problem as you do and for general "power-line" noise, my KNB2 is useless -
however, there is a certain "pop, popping, frying" noise that is S9+30 on 80
meters that it eliminates completely!!  Too bad I don't operate 80!

I'd be glad to beta test something if anyone's got some mods (yes, I already
tried changing the "NB2" capacitor a number of times all to no avail).  Now
before anyone gets too terribly defensive, I've already rated my K2 as way
above my Pro II and the Mark V - but simply put, the noise blanker could use
some technical attention.  73 es Happy New Year --Don N4HH
K2/100/#2028/KPA100, etc. etc.

----- Original Message -----
From: "Thom R. Lacosta" <[hidden email]>
To: "Marinos Markomanolakis, M.D." <[hidden email]>
Cc: <[hidden email]>
Sent: Sunday, January 02, 2005 12:05 PM
Subject: Re: [Elecraft] Question about KNB2 Noise Blanker


> On Sun, 2 Jan 2005, Marinos Markomanolakis, M.D. wrote:
<snip>
> Couldn't agree more...I live in a very old part of the city
here...surrounded by
> industrial users of power, a leaking power grid and a utility that doesn't
care.
<snip>



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[Bryce A. Carr]

Partial repeat of Marinos Markomanolakis, M.D. 2 Jan/05

> For a receiver of the K2 caliber, I believe, it is worth every penny and
> construction effort, even if it means incorporating a "pre-made" surface
> mount module for the NB in order to improve on the NB area which seems to
be
> suboptimal.
> For example an "expensive and/or difficult to build" but optimized NB
module
> will be FAR more desirable and effective feature in a real world Rx
> performance improvement rather than a similar DSP module that is already
> available from Elecraft.
>
> These are my $.02 opinion about the NB, which may be the only area that
> needs some improvement in a radio that has no equal in the market today.
And
> can definitely make a difference for people wanting to have a K2 as their
> only/main rig in a urban QTH....as most of us live.
>
> 73,
> Marinos, ki4gin

Excellent Marinos. Thats what I wanted to say! I am using my K2 as my main
rig due to it's excellent features except when I must switch due to city
noise. I do, of course, have a variable gain preamp that I built for my
80/160 phased loops  that in turn feeds my K2 so I have plenty of rf  at the
blanker input.and the scope confirms it. There is nothing wrong with the
blanking pulse widths. This low level city hash is simply not triggering the
blanking mv due to other blanker problems.
With my old Kenwood TS-140S and other rigs I typically see a 3 S unit drop
in a S4 city noise floor and the weak ones jump out of it. We 160m noise
eaters would buy a good RF noise blanker even if the box was  twice the size
of the K2.                                  Aloha, Bryce, kh6at

>
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