Elecraft

RE: How does K2 NB work?

Classic

List

Threaded

7 messages Options

David Walker-8

RE: How does K2 NB work?

It doesn't. Don't waste your time on this option.

> Thinking of building my 2nd K2. I wondered what
> the consensus is on HOW WELL DOES THE NB WORK?in a K2?
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

Jim Sheldon

RE: RE: How does K2 NB work?

A blanket "It doesn't. Don't waste your time--" isn't really a good thing
to say at this time. #1, it DOES work on many types of impulse noise. If
you are looking to eliminate atmospheric static noise (QRN) then yes, it
doesn't work. Pulse type ignition noise from vehicles passing your
location, or running near you, it does an excellent job of removing. Also,
much of the power line noise caused by leaky/cracked insulators and bad
grounds on your nearby power lines are usually effectively removed by the
KNB2. This is what the KNB2 was designed to do, and it is actually better
at this job than the NB in my IC-706MKIIG and other rigs I have had in the
past.

Again, if you are trying to eliminate QRN, there isn't anything available in
ANY rig that I know of that will do that.

Another thing to consider -- any time the noise blanker is ON, it will cause
distortion in the received audio of the station you are listening to if
there is a reasonably strong signal within 5 to 10 KHz of the signal you are
trying to receive. This occurs with ANY noise blanker, not just the KNB2.

Jim Sheldon, W0EB
K2 #4338

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of David Walker
> Sent: Sunday, August 27, 2006 6:26 AM
> To: [hidden email]
> Subject: [Elecraft] RE: How does K2 NB work?
>
> It doesn't. Don't waste your time on this option.
>
>
> > Thinking of building my 2nd K2. I wondered what
> > the consensus is on HOW WELL DOES THE NB WORK?in a K2?
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

w6jd

Re: RE: How does K2 NB work?

In reply to this post by David Walker-8

Mine works just fine on the noises I have to deal with. I live on a busy street and it handles ignition noise with no problems and most of my power line noise.

Doug
W6JD

-------------- Original message --------------
From: "David Walker" <[hidden email]>

> It doesn't. Don't waste your time on this option.
>
>
> > Thinking of building my 2nd K2. I wondered what
> > the consensus is on HOW WELL DOES THE NB WORK?in a K2?
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

Ron D'Eau Claire-2

RE: RE: How does K2 NB work?

The noise blanker works extremely well on repetitious, high-amplitude pulse
type noise such as that put out by cheap lamp dimmers, auto ignition, etc.
The dimmers are more of a nemesis on the lower frequency bands were auto
ignition is more of a problem on the higher frequency bands.

Basically, the blanker works by noting the interval of a train of pulses and
then turning off (blanking) the signal path for an instant when the each
pulse occurs. That effectively makes the pulses disappear.

Having used my K2 in areas where I could not get away from those cheap lamp
dimmers, it made the difference between hearing a roar of S9+ noise to
having the background drop to an S1 or S2 level of typical band QRN.

The blanker can't do much of anything if the noise does not consist of a
train of high-amplitude pulses. Typical noises it can't handle are the hash
from motor commutators, the frying sounds one sometimes gets from leaky
power line insulators, etc. But it's FB on "popping" arcs that sometimes
occur on power lines and anything else that is high-amplitude and
repetitious.

Even so, there is a downside to any noise blanker. It is punching holes in
the signal path. They are too short to hear, so the noise just goes away.
But that action of switching the I.F. signal path off then on again produces
frequency "mixing", just like any frequency converter or "mixer". As a
result, various frequencies in the I.F. path might produce mixing products
that appear as spurious signals or other noise! That's why Elecraft
recommends you turn the blanker OFF when you don't need it.

Ron AC7AC

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

AA5CK

Re: RE: How does K2 NB work?

In reply to this post by David Walker-8

If you have any doubts whether your K2NB can handle pulse type noise
here are a couple of simple circuits that can either ease your mind or
send it to the bench.

The first is a pulse-generator/signal tracer/audio amp that works well
as such and produces a 10uS pulse. A 2N3904 and 2N3906 may be used.

http://www.electronics-lab.com/projects/oscillators_timers/012/index.html

The second produces pulse widths of approx. 10uS to 500uS with C1 values
between 470pF and .047uF.

http://www.electronics.50g.com/cpg.htm

Also don't forget, as others on the list have noted, sometimes the
preamp must be used to amplify the noise enough to trigger the K2NB.

Good Luck...Ted...aa5ck

David Walker wrote:
> It doesn't. Don't waste your time on this option.
>
>
>> Thinking of building my 2nd K2. I wondered what
>> the consensus is on HOW WELL DOES THE NB WORK?in a K2?
>
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

Tom Hammond-3

Re: RE: How does K2 NB work?

Fellas:

For an off-the-air demo of how well MY KNB2 works, you might want to check out:

http://www.n0ss.net/knb2_demo.zip

This recording was made during a real-time QSO, and NOTHING special
was done. I just hooked the K2's AF output to the laptop PC and
started recording while I enabled the KNB2 and then stepped thru the
two available modes.

The file is ZIPped because it's really a 2MB WAV file. SO you'll have
to UNZIP it before you run it.

Enjoy!

73,

Tom Hammond N0SS

At 02:58 PM 8/27/2006, AA5CK wrote:

>If you have any doubts whether your K2NB can handle pulse type noise
>here are a couple of simple circuits that can either ease your mind
>or send it to the bench.
>
>The first is a pulse-generator/signal tracer/audio amp that works
>well as such and produces a 10uS pulse. A 2N3904 and 2N3906 may be used.
>
>
>http://www.electronics-lab.com/projects/oscillators_timers/012/index.html
>
>The second produces pulse widths of approx. 10uS to 500uS with C1
>values between 470pF and .047uF.
>
> http://www.electronics.50g.com/cpg.htm
>
>Also don't forget, as others on the list have noted, sometimes the
>preamp must be used to amplify the noise enough to trigger the K2NB.
>
>Good Luck...Ted...aa5ck
>
>David Walker wrote:
>>It doesn't. Don't waste your time on this option.
>>
>>
>>>Thinking of building my 2nd K2. I wondered what
>>>the consensus is on HOW WELL DOES THE NB WORK?in a K2?
>>
>_______________________________________________
>Elecraft mailing list
>Post to: [hidden email]
>You must be a subscriber to post to the list.
>Subscriber Info (Addr. Change, sub, unsub etc.):
>http://mailman.qth.net/mailman/listinfo/elecraft
>
>Help: http://mailman.qth.net/subscribers.htm
>Elecraft web page: http://www.elecraft.com

Vin Cortina

Re: RE: How does K2 NB work?

Sure makes the point, Tom.

Vin KR2F

K1-4 s/n:1977
KX1 s/n:1476

----- Original Message -----
From: "Tom Hammond" <[hidden email]>
To: "David Walker" <[hidden email]>
Cc: <[hidden email]>
Sent: Sunday, August 27, 2006 4:37 PM
Subject: Re: [Elecraft] RE: How does K2 NB work?

> Fellas:
>
> For an off-the-air demo of how well MY KNB2 works, you might want to check
> out:
>
> http://www.n0ss.net/knb2_demo.zip
>
> This recording was made during a real-time QSO, and NOTHING special was
> done. I just hooked the K2's AF output ...

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com