Best way to use NB and NR?

[tomb18]

Hi,
I was wondering if anyone could give me some hints as to the best way to use the NB and the NR?
Most of the time I use the nr and there seems to be little effect of the nb (maybe one-two s units?)  Does the nb take away from faint signals?  If not should I always just use it?
Thanks

[Don Wilhelm-4]

The K3 noise blanker, and in fact any noise blanker works by producing
"holes" in the receive path.  That is what blanking means - if an
impulse is detected, it shuts off the receive path for a specified
period of time.

That will not "take away" from the reception of faint signals, but if
combined with gaps in the received signals because of impulse events
occurring at the receiving station, it may make the copy of faint
signals difficult because of the blanks in the received data stream.

In my opinion, it should only be used when necessary, not all the time.  
If you have constant static pulses or automotive ignition noise or
distant lightning surge problems at your QTH, then it may be beneficial
to run the NB at all times, but if you do not need it, keep it off.  
Remember that the NB responds to impulse noise - it will not be
effective in reducing slow rise time noise like atmospheric noise or
power-line induced noise.  NB needs a fast rise time to be effective.

NR is a different animal altogether.  It will reduce or eliminate things
like atmospheric noise or power line noise - it works on correlation
principles.  That means is it is normally quiet while it looks for what
might be a valid signal.  When it finds something that appears to be a
valid signal, it builds a filter around it and sends that result to the
K3 audio.  What it looks for is highly dependent on the parameters set
for the K3 NR algorithm as well as your local noise.  There are several
settings provided for in the menu.  Do a little experimenting with your
chosen mode and local noise situation until you discover what works best
for you.  The settings for CW will likely not be good for SSB.  Try the
settings to find which works for your particular situation.  This is not
a case of "one size fits all", customize it to your particular noise
source.   With NR on, the desired signal should be enhanced, but really
weak signals may be at or near the noise level, and may not appear as a
valid signal, giving the appearance that weak signals may be covered up
and not detected.  I suggest (after experimenting) that you normally run
with NR turned off, but turn it on if the situation warrants it.

73,
Don W3FPR

On 9/29/2011 12:15 PM, tomb18 wrote:
> Hi,
> I was wondering if anyone could give me some hints as to the best way to use
> the NB and the NR?
> Most of the time I use the nr and there seems to be little effect of the nb
> (maybe one-two s units?)  Does the nb take away from faint signals?  If not
> should I always just use it?
>
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[Bob K6UJ]

Wow Don,  great explanation !

Bob
K6UJ




On Sep 29, 2011, at 8:51 PM, Don Wilhelm wrote:

> The K3 noise blanker, and in fact any noise blanker works by producing
> "holes" in the receive path.  That is what blanking means - if an
> impulse is detected, it shuts off the receive path for a specified
> period of time.
>
> That will not "take away" from the reception of faint signals, but if
> combined with gaps in the received signals because of impulse events
> occurring at the receiving station, it may make the copy of faint
> signals difficult because of the blanks in the received data stream.
>
> In my opinion, it should only be used when necessary, not all the time.  
> If you have constant static pulses or automotive ignition noise or
> distant lightning surge problems at your QTH, then it may be beneficial
> to run the NB at all times, but if you do not need it, keep it off.  
> Remember that the NB responds to impulse noise - it will not be
> effective in reducing slow rise time noise like atmospheric noise or
> power-line induced noise.  NB needs a fast rise time to be effective.
>
> NR is a different animal altogether.  It will reduce or eliminate things
> like atmospheric noise or power line noise - it works on correlation
> principles.  That means is it is normally quiet while it looks for what
> might be a valid signal.  When it finds something that appears to be a
> valid signal, it builds a filter around it and sends that result to the
> K3 audio.  What it looks for is highly dependent on the parameters set
> for the K3 NR algorithm as well as your local noise.  There are several
> settings provided for in the menu.  Do a little experimenting with your
> chosen mode and local noise situation until you discover what works best
> for you.  The settings for CW will likely not be good for SSB.  Try the
> settings to find which works for your particular situation.  This is not
> a case of "one size fits all", customize it to your particular noise
> source.   With NR on, the desired signal should be enhanced, but really
> weak signals may be at or near the noise level, and may not appear as a
> valid signal, giving the appearance that weak signals may be covered up
> and not detected.  I suggest (after experimenting) that you normally run
> with NR turned off, but turn it on if the situation warrants it.
>
> 73,
> Don W3FPR
>
> On 9/29/2011 12:15 PM, tomb18 wrote:
>> Hi,
>> I was wondering if anyone could give me some hints as to the best way to use
>> the NB and the NR?
>> Most of the time I use the nr and there seems to be little effect of the nb
>> (maybe one-two s units?)  Does the nb take away from faint signals?  If not
>> should I always just use it?
>>
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> Elecraft mailing list
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> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

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[Dan Sherwood]

As a brand new K3 user, I find some of the NR DSP settings quite perplexing.
In working some nets, e.g. MARS, I've found some stations' audio almost
totally suppressed, while others enhanced.  Unfortunately, this process is
not consistent, but changes as the "noise picture" changes. Trial and error
methodology rules the day here.

On a lighter note, an algorithm that consistently suppresses an individual
station could come in handy.  Certainly would consider a 2M XVTR module to
run on our local repeater!

I would be interested if there's a "White Paper" somewhere on the Elecraft
web site, (or elsewhere), with an in-depth explanation of what the various
settings do.

73,

Dan
WA6PZK



On 9/29/11 8:51 PM, "Don Wilhelm" <[hidden email]> wrote:

> The K3 noise blanker, and in fact any noise blanker works by producing
> "holes" in the receive path.  That is what blanking means - if an
> impulse is detected, it shuts off the receive path for a specified
> period of time.
>
> That will not "take away" from the reception of faint signals, but if
> combined with gaps in the received signals because of impulse events
> occurring at the receiving station, it may make the copy of faint
> signals difficult because of the blanks in the received data stream.
>
> In my opinion, it should only be used when necessary, not all the time.
> If you have constant static pulses or automotive ignition noise or
> distant lightning surge problems at your QTH, then it may be beneficial
> to run the NB at all times, but if you do not need it, keep it off.
> Remember that the NB responds to impulse noise - it will not be
> effective in reducing slow rise time noise like atmospheric noise or
> power-line induced noise.  NB needs a fast rise time to be effective.
>
> NR is a different animal altogether.  It will reduce or eliminate things
> like atmospheric noise or power line noise - it works on correlation
> principles.  That means is it is normally quiet while it looks for what
> might be a valid signal.  When it finds something that appears to be a
> valid signal, it builds a filter around it and sends that result to the
> K3 audio.  What it looks for is highly dependent on the parameters set
> for the K3 NR algorithm as well as your local noise.  There are several
> settings provided for in the menu.  Do a little experimenting with your
> chosen mode and local noise situation until you discover what works best
> for you.  The settings for CW will likely not be good for SSB.  Try the
> settings to find which works for your particular situation.  This is not
> a case of "one size fits all", customize it to your particular noise
> source.   With NR on, the desired signal should be enhanced, but really
> weak signals may be at or near the noise level, and may not appear as a
> valid signal, giving the appearance that weak signals may be covered up
> and not detected.  I suggest (after experimenting) that you normally run
> with NR turned off, but turn it on if the situation warrants it.
>
> 73,
> Don W3FPR
>
> On 9/29/2011 12:15 PM, tomb18 wrote:
>> Hi,
>> I was wondering if anyone could give me some hints as to the best way to use
>> the NB and the NR?
>> Most of the time I use the nr and there seems to be little effect of the nb
>> (maybe one-two s units?)  Does the nb take away from faint signals?  If not
>> should I always just use it?
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

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[KK7P]

This is true of the hardware blanker in the K3.

The DSP blanker works on a different principle, in part
because the noise pulse has potentially been "stretched"
by the selectivity of the roofing filter.

In the DSP blanker, for the duration of the noise pulse, a
locally generated signal is substituted.  The amplitude is
computed from the signal prior to the noise pulse, and the
phase is extracted from the incoming signal+pulse.

This is why it pays to play with BOTH noise blanker
parameters with the K3.  Depending on the type of impulse
noise (ignition, power line arcing, electric fence, etc.),
one may be much more effective than the other, or certain
qualities of each may be usefully employed to minimize
communications disruption.


73,

Lyle KK7P

> The K3 noise blanker, and in fact any noise blanker
>works by producing "holes" in the receive path...
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[tomb18]

Thanks for the great explanations.

[Phil Shepard]

Tomorrow is North America's Summits on the Air (SOTA) Day.  There will be a
much larger than usual amount of SOTA activity tomorrow in the US and
Canada.  Over 30 different summit activations are already publicized, and
more are being added hourly.  These stations will be set up on prominent
mountain tops.  The hams hiked there and set up portable stations, and a lot
of Elecraft rigs will be heard.  I use a K2 and wire antennas.  The
activations will start around 1400z and run throughout the day.  The SOTA
Watch site, www.sotawatch.org, lists the activations - The "Alerts" page
lists those planned, and the "Spots" page shows the spots for those already
on the air.  More information about SOTA can be found at www.sota.org.uk.

Chasing summits is an informal and very enjoyable ham radio activity.  Why
not join in by working some summits tomorrow!  As the SOTA Watch site shows,
the activations are often centered around QRP frequencies.  There will be
activations from HF through VHF/UHF, with FM, SSB and CW operation.  Keep
track of the stations that you work - you can log them into the SOTA
database and work toward certificates and trophies.  It's fun - give it a
try!

See you from the summits.

73,

Phil, NS7P

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