[K3] Noise Blanking, all-mode squelch- any strategies for settings?

[Arlen Fletcher]

Greetings Elecrafters,

I’m new to the K3 (and HF in general), and I’m trying to sort out how to get useful results from the Noise Blanking (NB) features.

I’m looking for strategies, tips, techniques, etc. for selecting the settings for NB. With over 14,000 possible settings between the IF NB and the DSP NB (according to KE7X’s K3 book), I find myself getting overwhelmed and I give up on NB. Honestly, I can hear very little difference as I go through the various NB settings, so how am I suppose to choose the ‘right’ one?

I operate SSB almost exclusively, and I don’t use all-mode squelch  - but I need to experiment with this. I’d appreciate hearing your take on squelch.

What’s your secret recipe for picking NB settings that work?

Thanks!

73, Arlen, AA7F

______________________________________________________________
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
Message delivered to [hidden email]

[Bill-3]

As no one has responded yet, I'll throw in my most recent experience:

I assume you meant to say Noise Reduction - a mistake I made a couple of
months ago. Although I was quickly informed of my mistake, I never did
receive any really useful information regarding the many settings
available on the K3.

My specific question involved thunderstorm static - for which the K3 is
no better than any other rig. In fact, it handles the noise less well
than a couple of my other rigs. Hence, I do not use the K3 during high
static conditions.

Be aware that many answers will be sent to you via direct email, rather
than on this reflector. Should one of them be informative, please post
same - in order that we may all learn.

Bill W2BLC K-Line


______________________________________________________________
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
Message delivered to [hidden email]

[JHRichards]

Hi Arlen  -  I, too, seek just such a general guide for using the
various noise reduction features on modern transceivers, but have yet to
find one.  Transceiver user manuals are typically pretty lean on real
world explanation - they enumerate the features, point out what button
or knob makes an adjustment, but there is a paucity of explanation on
how and when to use those features on the air.  This is a problem with
many other features on these radios.  Moreover, the manuals rarely
explain how an one feature relates to the another noise reducing
features, including the NB Noise Blanker, BW Bandwidth, PBT Pass band,
RF-Gain, and other controls, which, when used together, work pretty well.

Modern transceivers like the K3 have different tools for different
problems.  I recommend a detailed web search for articles and comments
that explain how these various systems work, in general, and which work
best on what types of noise, in particular.  Eventually, you will
assemble enough information to better understand how these features
operate and interact.  I have yet to find a single, comprehensive
explanation in real world terms... and I have looked!

Sometimes a combination of adjustments will get the click.  Sometimes
nothings gets the click.  This research will pay dividends and you will
learn about the K3 and other radios as well.

In any case, there are no free lunches, these tools alter incoming
signals, causing, in turn, some level of distortion and impose unwanted
digital "artifacts" - hopefully resulting in greater intelligibility,
but with some fallout or deleterious impact in the signal.  You trade
off one for the other, and hopefully don't go too far and make things
worse, which is easy to do.  Used in moderation, audio quality is
sacrificed to some degree to achieve better intelligibility.

The first thing you must determine is which type of noise is tackled by
each noise reducing feature.  For example, and it varies from rig to
rig, but generally (speaking in very general and not scientific terms
lest I generalize too much) -  DSP NR attempts to reduce random noise
like atmospheric static and general hiss which covers a weak signal. The
NB Noise Blanker typically reduces repetitive pulse type noise like
ignition sparking, and some NB circuits are geared more to reducing the
heavier pulsing of radar systems, like what SW listeners call the
Russian Woodpecker.   The AN or Auto Notch seeks out and removes one or
more constant tones, like when someone is tuning his antenna tuner right
over your QSO.  A manual notch does that manually, you gotta adjust it
out, frequency and bandwidth are user selected.  The PBT or Pass band
Tuning control allows you to shift the receiver pass band left of right
to avoid a problem signal on one or the other side of the signal you
want.  You get less of the desired signal, but maybe none or far less of
the offending signal that way.   RF-Gain can often be used to lower
signal and noise (so to speak) and you end up with less noise and less
signal, but maybe a better signal-to-noise ratio where noise is less
noticeable against the resulting signal volume.

You should research how each one works, on transceivers generally, and
the K3 in particular, and EXPERIMENT with each individually and blended
with others for best advantage, each situation may vary from another in
some way.

There are few concise explanations, so it may take some time to assemble
a comprehensive explanation, but the effort will pay dividends on your
time investment.

Good luck.
--------------------- K8JHR  ---------------------

______________________________________________________________
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
Message delivered to [hidden email]

[k6dgw]

I'll try.  The short answer, in case you're not into an explanation is:
"It all depends on your circumstances, the character of your noise, the
strength of the signal you're trying to copy, how much distortion you're
willing to tolerate ... and sometimes the phase of the moon."  No one
can give someone else a set of numbers that will work in every case.

The K3 has two Noise Blankers and a DSP Noise Reduction feature.

Noise blankers do exactly what their name implies ... when a sharp noise
pulse comes along, they simply punch a hole in the signal [mute the
receiver] for a short period.  The adjustable things are generally the
length of the "hole" and some form of threshold setting that determines
when it decides it's a noise pulse.

The K3 has one hardware NB at the 1st IF [8 MHz] that works essentially
like any other NB.  It also has one in the DSP firmware that operates on
the "number soup" from the ADC.  It too blanks the signal for variable
times and under variable conditions ... because it's doing it with
arithmetic and not hardware components, it can be somewhat more precise.

Noise blankers are effective against repetitive short pulse noise such
as ignition noise from a vehicle [not nearly as common as 40 years ago]
and precipitation static.  They are *not* very effective against power
line hash although sometimes they'll knock it down some if it has a
short repetitive component.  They are not effective against T-storm
static much at all.

Obviously, punching holes in the signal distorts it and the longer the
holes, the more distortion.  As you increase the aggressiveness of the
NB, you'll start trading noise for distortion, so the basic rule is, use
as little as possible.  They're not magic.

Noise Reduction on the other hand all happens in the DSP.  There are
various approaches to it, in the K3, the DSP algorithm builds a variable
filter on the fly to enhance the desired signal, thus appearing to lower
the noise.  How well it works depends on it's ability to identify the
signal components separate from the noise.  I have found it to be much
more effective on SSB than CW with very narrow bandpass.  I rarely
operate SSB so mine doesn't get much use.

The "aggressiveness" of the NR is adjustable in the K3.  The first half
of the available settings operate on the signal and what you hear is the
result.  The second half mix in some non-NR'd signal with the output.
The general rule for NB [as little as necessary] sort of applies to NR
too, and again, no one can tell you exactly how to use it.  That's a lot
of words to say, "NR isn't magic either."

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

On 7/29/2014 9:48 AM, Arlen Fletcher wrote:

> Greetings Elecrafters,
>
> I’m new to the K3 (and HF in general), and I’m trying to sort out how
> to get useful results from the Noise Blanking (NB) features.
>
> I’m looking for strategies, tips, techniques, etc. for selecting the
> settings for NB. With over 14,000 possible settings between the IF NB
> and the DSP NB (according to KE7X’s K3 book), I find myself getting
> overwhelmed and I give up on NB. Honestly, I can hear very little
> difference as I go through the various NB settings, so how am I
> suppose to choose the ‘right’ one?
>
> I operate SSB almost exclusively, and I don’t use all-mode squelch  -
> but I need to experiment with this. I’d appreciate hearing your take
> on squelch.
>
> What’s your secret recipe for picking NB settings that work?

______________________________________________________________
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
Message delivered to [hidden email]

[k6dgw]

Fred Cady's book has more the approach you're probably looking for.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

On 7/29/2014 1:51 PM, K8JHR wrote:

> Hi Arlen  -  I, too, seek just such a general guide for using the
> various noise reduction features on modern transceivers, but have yet to
> find one.  Transceiver user manuals are typically pretty lean on real
> world explanation - they enumerate the features, point out what button
> or knob makes an adjustment, but there is a paucity of explanation on
> how and when to use those features on the air.  This is a problem with
> many other features on these radios.  Moreover, the manuals rarely
> explain how an one feature relates to the another noise reducing
> features, including the NB Noise Blanker, BW Bandwidth, PBT Pass band,
> RF-Gain, and other controls, which, when used together, work pretty well.

______________________________________________________________
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
Message delivered to [hidden email]

[Jim Brown-10]

On 7/29/2014 2:58 PM, Fred Jensen wrote:
> Noise blankers do exactly what their name implies ... when a sharp
> noise pulse comes along, they simply punch a hole in the signal [mute
> the receiver] for a short period.  The adjustable things are generally
> the length of the "hole" and some form of threshold setting that
> determines when it decides it's a noise pulse.

Fred has given you a great explanation and excellent advice. I'll add a
bit of clarification. A Noise Blanker does NOT do much (if anything) on
broadband random noise. Rather, it works mostly on various forms of
man-made noise. Much of the noise I hear comes and goes, and/or is
different on different bands.

As Fred has made clear, less is more -- when I use the NB, I often do a
long push on the knob to enter setup mode, and reset both the DSP and
the IF to those best compromise minimum values that reduce the noise
without chopping too much of the audio.

It also helps to RTFM, which has some advice about what the DSP NB does
and what the IF NB does.

73, Jim K9YC
______________________________________________________________
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
Message delivered to [hidden email]

[alsopb]

Something missed in this discussion.

When you change a NB/NR setting, don't expect a instantaneous change.
Count to five and then conclude whether a setting change helped or not.

In some past posting, this was pointed out by Elecraft.

73 de Brian/K3KO

On 7/30/2014 15:45, Jim Brown wrote:

> On 7/29/2014 2:58 PM, Fred Jensen wrote:
>> Noise blankers do exactly what their name implies ... when a sharp
>> noise pulse comes along, they simply punch a hole in the signal [mute
>> the receiver] for a short period.  The adjustable things are generally
>> the length of the "hole" and some form of threshold setting that
>> determines when it decides it's a noise pulse.
>
> Fred has given you a great explanation and excellent advice. I'll add a
> bit of clarification. A Noise Blanker does NOT do much (if anything) on
> broadband random noise. Rather, it works mostly on various forms of
> man-made noise. Much of the noise I hear comes and goes, and/or is
> different on different bands.
>
> As Fred has made clear, less is more -- when I use the NB, I often do a
> long push on the knob to enter setup mode, and reset both the DSP and
> the IF to those best compromise minimum values that reduce the noise
> without chopping too much of the audio.
>
> It also helps to RTFM, which has some advice about what the DSP NB does
> and what the IF NB does.
>
> 73, Jim K9YC
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2012.0.2247 / Virus Database: 3955/7446 - Release Date: 07/30/14
>
>

______________________________________________________________
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
Message delivered to [hidden email]

Arlen,

One thing to keep in mind regarding NB and NR is that only the NB can
actually (sometimes) reduce the noise floor to the point where you will be
able to hear weak signals that are far below the noise floor that you
would have when NB is NOT engaged. In other words, when engaged and
properly set for the offending noise, the NB --may-- actually drop the
noise floor to what it would be if the interfering noise were not there at
all.

So far, I've never heard any NR function reduce the actual noise floor.
Yes, it can make the noise a bit less annoying, but it will rarely, if
ever, enable you to copy a signal that you would otherwise be unable to
copy if NR were off.

All that said, the K3's Noise Blanker (NB) is the most effective NB that I
have ever used on any radio for the line noise racket that occasionally
threatens to infringe upon my ham radio time.

73, Dale
WA8SRA

> Greetings Elecrafters,
>
> I’m new to the K3 (and HF in general), and I’m trying to sort out how to
> get useful results from the Noise Blanking (NB) features.
>
> I’m looking for strategies, tips, techniques, etc. for selecting the
> settings for NB. With over 14,000 possible settings between the IF NB and
> the DSP NB (according to KE7X’s K3 book), I find myself getting
> overwhelmed and I give up on NB. Honestly, I can hear very little
> difference as I go through the various NB settings, so how am I suppose to
> choose the ‘right’ one?
>
> I operate SSB almost exclusively, and I don’t use all-mode squelch  - but
> I need to experiment with this. I’d appreciate hearing your take on
> squelch.
>
> What’s your secret recipe for picking NB settings that work?
>
> Thanks!
>
> 73, Arlen, AA7F
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

______________________________________________________________
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
Message delivered to [hidden email]

[Don Wilhelm-4]

There is no 'secret recipe'.
As has been pointed out by several others, the NB settings must be
adjusted to best deal with the noise you are encountering at any given
time on any given band. Also, when dealing with the DSP based Noise
Blanker, give it a little time to build the filter that will be used to
do the job - count to 5 is a good suggestion. If you are using the
hardware NB, you should hear the effects almost immediately.

Listen to the noise before deciding whether NB or NR is the proper tool
to use. The NB works on high rise time, short impulse noise. It will not
be effective at all on more constant noise sources like powerline or AC
motor noise - those type noises will respond to the NR settings.

Noise Blanking is just what it says - it puts a blank 'hole' in the
receiver stream, and yes the K3 allows you to adjust it to control not
only the threshold where it begins to act, but also the width of the
blanking. You as a listener must come to a compromise - if the blanking
width is too wide for the transmission mode, those holes will begin to
disrupt the communications as the width becomes wider.

With Noise Reduction, the DSP builds a filter around what it detects to
be a coherent signal. It takes a little time for the DSP to sense that
it has a coherent signal and build that filter. You will also find that
the NR function will cause distortion when that filter is narrow. How
effective NR will be depends on the relative strength of the noise and
the signal that you want to hear.

So experiment a bit and you will become more adept at selecting between
NB and NR as the occasion arises. It is not a "catch all" for all noise
sources. Your selection and settings will vary from time to time and
band to band. I suggest running most of the time with both NB and NR off
and letting your brain do most of the filtering. When that is
bothersome, turn the appropriate one on and find the best settings that
attack your particular noise source.

73,
Don W3FPR

On 7/30/2014 6:14 PM, [hidden email] wrote:
> What’s your secret recipe for picking NB settings that work?
>
>

______________________________________________________________
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
Message delivered to [hidden email]