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RLVZ

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Dick Van Zandt (K9OM) has sent you a forum message for you to review.

----- start of message -----
"Noisy DSP experiences".

Forum: Articles
Subject: An Interesting CQ WPX CW Experience

The "noisy DSP" phenomena is well known. Rob Sherwood has also identified this problem and has written about it.

I have the following radios
K3
K2
Flex5000
IC7700
Perseus

ALL the above radios except the K2suffer from the noisy front end problem when mild QRN is around. It sounds like these radios have a reverb unit on the receiver which multiplies static and pulse noise.

Elecraft claims to have a cure for this problem, however I still find the receiver noisy. The K2 I prefer over the K3 on CW when there is QRN around. The filters on the K2 sound better on CW when there is QRN about.

It amazes me every time that I turn on any of my old old analog radios like the TS830S or the FT1000D and do a comparison. The QRN all of a sudden becomes tolerable and not so nerve wrecking.

The TS830S is still my favorite low band radio for picking weak signals out of QRN on 160 and 80 meters. This is especially so when there is a lot static and QRN around.

Its unfortunate that there is no current model analog transceiver manufactured that has fantastic receiver dynamic range numbers like the Elecraft K3. The only option available is to build your own like the PA3AKE H-mode mixer high performance receiver.

http://www.xs4all.nl/~martein/pa3ake/hmode/

----- end of message -----

You can see this forum message in full at:

http://eham.net/forums/Articles/201100

This email was sent to you from Dick Van Zandt (K9OM) through a notification
system on eHam.net.

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Vic K2VCO

Re: eHam.net forum message

I wonder if he is talking about QRN from storms, etc. or manmade QRN?

I've heard this before. The K3's AGC pulse rejection feature is intended to improve
performance in this area.

Has anyone tried to quantify or describe this better? It would need to be done with an a/b
comparison. It's not so easy to describe types of QRN, either. 'QRN' is meaningless,
because of the huge differences in the nature of noise, which anyone who tries to compare
noise blankers, for example, soon learns!

On 7/13/2010 9:37 PM, [hidden email] wrote:

>
>
> Dick Van Zandt (K9OM) has sent you a forum message for you to review.
>
>
> ----- start of message ----- "Noisy DSP experiences".
>
> Forum: Articles Subject: An Interesting CQ WPX CW Experience
>
> The"noisy DSP" phenomena is well known. Rob Sherwood has also identified this
> problem and has written about it.
>
> I have the following radios K3 K2 Flex5000 IC7700 Perseus
>
> ALL the above radios except the K2suffer from the noisy front end problem when mild
> QRN is around. It sounds like these radios have a reverb unit on the receiver which
> multiplies static and pulse noise.
>
> Elecraft claims to have a cure for this problem, however I still find the receiver
> noisy. The K2 I prefer over the K3 on CW when there is QRN around. The filters on the
> K2 sound better on CW when there is QRN about.
>
> It amazes me every time that I turn on any of my old old analog radios like the TS830S
> or the FT1000D and do a comparison. The QRN all of a sudden becomes tolerable and not
> so nerve wrecking.
>
> The TS830S is still my favorite low band radio for picking weak signals out of QRN on
> 160 and 80 meters. This is especially so when there is a lot static and QRN around.
>
> Its unfortunate that there is no current model analog transceiver manufactured that
> has fantastic receiver dynamic range numbers like the Elecraft K3. The only option
> available is to build your own like the PA3AKE H-mode mixer high performance
> receiver.
>
> http://www.xs4all.nl/~martein/pa3ake/hmode/

--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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Geoffrey Mackenzie-Kennedy

Re: eHam.net forum message

In reply to this post by RLVZ

Thank you for posting K9OM's comment.

FWIW I have a Perseus and two other receivers which both use H-Mode mixers,
one of which uses a version of PA3AKE's H-Mode front end.

With the Perseus used as a stand alone receiver, I have not experienced this
"noise problem" in the presence of mild or quite strong static or manmade
pulse QRN, UNLESS I wind up the Perseus' NR too far, then indeed there is
some tunnel/ reverberation effect, which can at times be annoying.

With the Perseus connected to the IF of either H-Mode receiver right after
the first mixer, mainly for use as a panadapter, I very seldom use the
Perseus' NR and then only at a low setting, and use the main receiver's LO
noise blanker if required..

73,

Geoff
GM4ESD

On Wednesday, July 14, 2010 5:37 AM, RLVZ wrote:

> Dick Van Zandt (K9OM) has sent you a forum message for you to review.

<snip>

> ALL the above radios except the K2suffer from the noisy front end problem
> when mild QRN is around. It sounds like these radios have a reverb unit
> on the receiver which multiplies static and pulse noise.
>
> Elecraft claims to have a cure for this problem, however I still find the
> receiver noisy. The K2 I prefer over the K3 on CW when there is QRN
> around. The filters on the K2 sound better on CW when there is QRN about.
>
> It amazes me every time that I turn on any of my old old analog radios
> like the TS830S or the FT1000D and do a comparison. The QRN all of a
> sudden becomes tolerable and not so nerve wrecking.
>
> The TS830S is still my favorite low band radio for picking weak signals
> out of QRN on 160 and 80 meters. This is especially so when there is a
> lot static and QRN around.
>
> Its unfortunate that there is no current model analog transceiver
> manufactured that has fantastic receiver dynamic range numbers like the
> Elecraft K3. The only option available is to build your own like the
> PA3AKE H-mode mixer high performance receiver.
>
> http://www.xs4all.nl/~martein/pa3ake/hmode/

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W8JI

Re: eHam.net forum message

>FWIW I have a Perseus and two other receivers which both use H-Mode mixers,
> one of which uses a version of PA3AKE's H-Mode front end.
>
> With the Perseus used as a stand alone receiver, I have not experienced
> this
> "noise problem" in the presence of mild or quite strong static or manmade
> pulse QRN, UNLESS I wind up the Perseus' NR too far, then indeed there is
> some tunnel/ reverberation effect, which can at times be annoying.

I think people are talking about two different things here.

What I am talking about, and what I understand some others to be talking
about, is a problem with DSP systems processing noise floor signal,
especially when the noise is a bit rough, without adding artifacts that make
copy or quality worse.

This is not anything to do with noise blanker use, which would have limited
use with a weak noise-floor signal.

Processing with a noise blanker punches a hole or reduces gain for fast
level increases, and noise blanking in a DSP is a different process. I'm not
sure what goes on now, but years ago when I worked on some DSP NR systems it
was necessary to compare many samples of signal and look for repeating
patterns that would be a steady signal and try to subtract out things that
did not repeat. This always caused a delay or echo or distortion, depending
on the aggressiveness of the noise reduction.

I fully expect any kind of blanker or processor to screw up the signal
characteristics. There is no way around it. :-) My concern is when the
processing is off and there should be a faithful accurate reproduction of
signal, even when it is below noise floor.

I have no problem at all with how the K3 blanker and noise reduction works,
and actually IMO it does a good job for me. I just don't think any DSP radio
is as good as a full analog system when signal levels are near noise levels,
especially when the noise floor is a bit rough.

73 Tom

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Geoffrey Mackenzie-Kennedy

Re: eHam.net forum message

Thanks for your explanation, I had missed the point of RLVZ's comment.

A related cause and I am speculating here without doing the calculations,
when the noise is rough and signals are at or under the noise floor might be
the added in-passband low level intermodulation products generated by a
narrow bandwidth roofing filter when hit by all of the received noise power,
which the DSP then has to cope with, given that the OIP3 of a narrow
bandwidth crystal filter is usually "worse" than that of a wider filter -
all else being equal. I do have some crystal filter OIP3 vs filter bandwidth
measured data which shows this effect, but will stop speculating on the
effect on a DSP :-)

I agree with your comment about DSP radios vs full analogue radios.

73,

Geoff
GM4ESD

Tom W8JI wrote:

> I think people are talking about two different things here.
>
> What I am talking about, and what I understand some others to be talking
> about, is a problem with DSP systems processing noise floor signal,
> especially when the noise is a bit rough, without adding artifacts that
> make
> copy or quality worse.

<snip>

> I have no problem at all with how the K3 blanker and noise reduction
> works,
> and actually IMO it does a good job for me. I just don't think any DSP
> radio
> is as good as a full analog system when signal levels are near noise
> levels,
> especially when the noise floor is a bit rough.

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Guy, K2AV

Re: eHam.net forum message

Would it be possible to add a function to the utility which creates a
file which lists all the K3 settings and configurations and control
settings when it is invoked? Something that could be cut and pasted
into an email or attached? This would be useful for many problem
resolve sessions.

I'm thinking that there are real issues here, solving or
identification made problematic by unintentionally fuzzy descriptions.
IF this could be boiled down to a certain kind of signal and
precisely defined settings producing a widely agreed upon result,
there could be a resolution. It is very hard to code solutions to
impressions, particularly it is not at all clear whether NR was on at
the same time, what settings were in use, and whether IF and/or DSP in
use for NB, etc, etc, etc.

Backing off PRE/ATT/RFgain settings in a noisy situation definitely
helps the "clarity" of DSP functions, but this tactic seems eternally
to fall on deaf ears.

It is clear in some posts that the term noise reduction is used when
the NB functions of the K3 are being addressed.

On the other side of this, I've never seen an analog radio nullify key
clicks. I don't think we know everything that is possible with DSP
processing in the digital realm given time? Very careful and precise
descriptions would be helpful.

73, Guy.

On Wed, Jul 14, 2010 at 2:54 PM, Geoffrey Mackenzie-Kennedy
<[hidden email]> wrote:

> Thanks for your explanation, I had missed the point of RLVZ's comment.
>
> A related cause and I am speculating here without doing the calculations,
> when the noise is rough and signals are at or under the noise floor might be
> the added in-passband low level intermodulation products generated by a
> narrow bandwidth roofing filter when hit by all of the received noise power,
> which the DSP then has to cope with, given that the OIP3 of a narrow
> bandwidth crystal filter is usually "worse" than that of a wider filter -
> all else being equal. I do have some crystal filter OIP3 vs filter bandwidth
> measured data which shows this effect, but will stop speculating on the
> effect on a DSP :-)
>
> I agree with your comment about DSP radios vs full analogue radios.
>
> 73,
>
> Geoff
> GM4ESD
>
>
>
> Tom W8JI wrote:
>
>> I think people are talking about two different things here.
>>
>> What I am talking about, and what I understand some others to be talking
>> about, is a problem with DSP systems processing noise floor signal,
>> especially when the noise is a bit rough, without adding artifacts that
>> make
>> copy or quality worse.
>
> <snip>
>
>> I have no problem at all with how the K3 blanker and noise reduction
>> works,
>> and actually IMO it does a good job for me. I just don't think any DSP
>> radio
>> is as good as a full analog system when signal levels are near noise
>> levels,
>> especially when the noise floor is a bit rough.
>
>
>
> ______________________________________________________________
> 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
>

Dick Dievendorff

Re: eHam.net forum message

This is a huge undertaking, and the MCU config variables are a moving target. But it is (low) on my list of possible K3 Utility enhancements.
Dick, K6KR

Sent from my iPhone

On Jul 14, 2010, at 12:41 PM, Guy Olinger K2AV <[hidden email]> wrote:

> Would it be possible to add a function to the utility which creates a
> file which lists all the K3 settings and configurations and control
> settings when it is invoked? Something that could be cut and pasted
> into an email or attached? This would be useful for many problem
> resolve sessions.
>
> I'm thinking that there are real issues here, solving or
> identification made problematic by unintentionally fuzzy descriptions.
> IF this could be boiled down to a certain kind of signal and
> precisely defined settings producing a widely agreed upon result,
> there could be a resolution. It is very hard to code solutions to
> impressions, particularly it is not at all clear whether NR was on at
> the same time, what settings were in use, and whether IF and/or DSP in
> use for NB, etc, etc, etc.
>
> Backing off PRE/ATT/RFgain settings in a noisy situation definitely
> helps the "clarity" of DSP functions, but this tactic seems eternally
> to fall on deaf ears.
>
> It is clear in some posts that the term noise reduction is used when
> the NB functions of the K3 are being addressed.
>
> On the other side of this, I've never seen an analog radio nullify key
> clicks. I don't think we know everything that is possible with DSP
> processing in the digital realm given time? Very careful and precise
> descriptions would be helpful.
>
> 73, Guy.
>
> On Wed, Jul 14, 2010 at 2:54 PM, Geoffrey Mackenzie-Kennedy
> <[hidden email]> wrote:
>> Thanks for your explanation, I had missed the point of RLVZ's comment.
>>
>> A related cause and I am speculating here without doing the calculations,
>> when the noise is rough and signals are at or under the noise floor might be
>> the added in-passband low level intermodulation products generated by a
>> narrow bandwidth roofing filter when hit by all of the received noise power,
>> which the DSP then has to cope with, given that the OIP3 of a narrow
>> bandwidth crystal filter is usually "worse" than that of a wider filter -
>> all else being equal. I do have some crystal filter OIP3 vs filter bandwidth
>> measured data which shows this effect, but will stop speculating on the
>> effect on a DSP :-)
>>
>> I agree with your comment about DSP radios vs full analogue radios.
>>
>> 73,
>>
>> Geoff
>> GM4ESD
>>
>>
>>
>> Tom W8JI wrote:
>>
>>> I think people are talking about two different things here.
>>>
>>> What I am talking about, and what I understand some others to be talking
>>> about, is a problem with DSP systems processing noise floor signal,
>>> especially when the noise is a bit rough, without adding artifacts that
>>> make
>>> copy or quality worse.
>>
>> <snip>
>>
>>> I have no problem at all with how the K3 blanker and noise reduction
>>> works,
>>> and actually IMO it does a good job for me. I just don't think any DSP
>>> radio
>>> is as good as a full analog system when signal levels are near noise
>>> levels,
>>> especially when the noise floor is a bit rough.
>>
>>
>>
>> ______________________________________________________________
>> 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
>>
> ______________________________________________________________
> 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

Don Cunningham

Re: eHam.net forum message

This very message and a host of others in the archives are the very reason I
own a K3 and have pre-ordered a P3. These guys listen to customer input,
respond, and fix things as soon as possible!!! The P3 does NOT do what I
really need in its initial form, BUT I am confident after emailing with P3's
design engineer that it will, in later updates, do all I need it to do. I
would never have this confidence with the major three manufacturers of ham
gear!!!!!! I have been a year trying to get Icom to make one, simple
firmware change to make the IC-7700 more user friendly on RTTY and am being
stonewalled. Thanks Elecraft for NOT acting like that!!!!!
73,
Don, WB5HAK
----- Original Message -----
From: "Dick Dievendorff" <[hidden email]>
To: "Guy Olinger K2AV" <[hidden email]>
Cc: <[hidden email]>; "Elecraft Discussion List" <[hidden email]>
Sent: Wednesday, July 14, 2010 2:52 PM
Subject: Re: [Elecraft] eHam.net forum message

> This is a huge undertaking, and the MCU config variables are a moving
> target. But it is (low) on my list of possible K3 Utility enhancements.
> Dick, K6KR
>
>
> Sent from my iPhone
>
> On Jul 14, 2010, at 12:41 PM, Guy Olinger K2AV <[hidden email]>
> wrote:
>
>> Would it be possible to add a function to the utility which creates a
>> file which lists all the K3 settings and configurations and control
>> settings when it is invoked? Something that could be cut and pasted
>> into an email or attached? This would be useful for many problem
>> resolve sessions.
>>
>> I'm thinking that there are real issues here, solving or
>> identification made problematic by unintentionally fuzzy descriptions.
>> IF this could be boiled down to a certain kind of signal and
>> precisely defined settings producing a widely agreed upon result,
>> there could be a resolution. It is very hard to code solutions to
>> impressions, particularly it is not at all clear whether NR was on at
>> the same time, what settings were in use, and whether IF and/or DSP in
>> use for NB, etc, etc, etc.
>>
>> Backing off PRE/ATT/RFgain settings in a noisy situation definitely
>> helps the "clarity" of DSP functions, but this tactic seems eternally
>> to fall on deaf ears.
>>
>> It is clear in some posts that the term noise reduction is used when
>> the NB functions of the K3 are being addressed.
>>
>> On the other side of this, I've never seen an analog radio nullify key
>> clicks. I don't think we know everything that is possible with DSP
>> processing in the digital realm given time? Very careful and precise
>> descriptions would be helpful.
>>
>> 73, Guy.
>>
>> On Wed, Jul 14, 2010 at 2:54 PM, Geoffrey Mackenzie-Kennedy
>> <[hidden email]> wrote:
>>> Thanks for your explanation, I had missed the point of RLVZ's comment.
>>>
>>> A related cause and I am speculating here without doing the
>>> calculations,
>>> when the noise is rough and signals are at or under the noise floor
>>> might be
>>> the added in-passband low level intermodulation products generated by a
>>> narrow bandwidth roofing filter when hit by all of the received noise
>>> power,
>>> which the DSP then has to cope with, given that the OIP3 of a narrow
>>> bandwidth crystal filter is usually "worse" than that of a wider
>>> filter -
>>> all else being equal. I do have some crystal filter OIP3 vs filter
>>> bandwidth
>>> measured data which shows this effect, but will stop speculating on the
>>> effect on a DSP :-)
>>>
>>> I agree with your comment about DSP radios vs full analogue radios.
>>>
>>> 73,
>>>
>>> Geoff
>>> GM4ESD
>>>
>>>
>>>
>>> Tom W8JI wrote:
>>>
>>>> I think people are talking about two different things here.
>>>>
>>>> What I am talking about, and what I understand some others to be
>>>> talking
>>>> about, is a problem with DSP systems processing noise floor signal,
>>>> especially when the noise is a bit rough, without adding artifacts that
>>>> make
>>>> copy or quality worse.
>>>
>>> <snip>
>>>
>>>> I have no problem at all with how the K3 blanker and noise reduction
>>>> works,
>>>> and actually IMO it does a good job for me. I just don't think any DSP
>>>> radio
>>>> is as good as a full analog system when signal levels are near noise
>>>> levels,
>>>> especially when the noise floor is a bit rough.
>>>
>>>
>>>
>>> ______________________________________________________________
>>> 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
>>>
>> ______________________________________________________________
>> 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
> ______________________________________________________________
> 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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Dunc Carter - W5DC

Re: eHam.net forum message

In reply to this post by RLVZ

Regarding key clicks. I suspect this may vary considerably with the
specific circumstances including the likelihood of considerable
variations in the individual transmitter rise and fall times and and the
roofing filter bandwidths.

Last November, I think, I read a suggestion about blanking key clicks
suggesting mainly the more extreme dsp settings, especially 3-7.

In the following 160 contest, one of the local contesters who uses Yaesu
equipment was kind enough to furnish loud key clicks that I was able to
test with, At the time, I had the nominal 250 Hz filter and the 2.8 KHz
filter with the 2.8 KHz filter being ineffective. Since I didn't have
an antenna set up for transmitting at the time, I was free to
experiment. The best blanking effect was with the 3-7 dsp setting and,
at roughly 130 Hz spacing from center on the high side of the 250 Hz
filter which has asymmetrical slopes, the click and other spur level was
reduced by four S-units on the K3 meter, allowing me to copy weak
signals at that separation. The analog blanker may have some effect on
the blanking of clicks but it wasn't nearly as obvious as the dsp
blanker. Since then, I've acquire a 500 Hz filter but I haven't had the
chance to test it in the same combat conditions. I don't know if the NR
would help with the 500 Hz filter; it does on other impulse noise
whereas the NR is fairly useless at 250 Hz.

Dunc, W5DC
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Terry Schieler

Re: eHam.net forum message

In reply to this post by Dick Dievendorff

That would be great, Dick. Guy has a very valuable suggestion there. I
know you've got a plate full before you, but if I had a nickel for every guy
on this reflector that asked me (or that I asked) for their settings, I'd
own four K3's instead of one. Thanks for your consideration on this.

Terry, W0FM

-----Original Message-----
From: Dick Dievendorff [mailto:[hidden email]]
Sent: Wednesday, July 14, 2010 2:52 PM
To: Guy Olinger K2AV
Cc: [hidden email]; Elecraft Discussion List
Subject: Re: [Elecraft] eHam.net forum message

This is a huge undertaking, and the MCU config variables are a moving
target. But it is (low) on my list of possible K3 Utility enhancements.
Dick, K6KR

Sent from my iPhone

On Jul 14, 2010, at 12:41 PM, Guy Olinger K2AV <[hidden email]>
wrote: