Re: [Elecraft] K2 noise on receiver when switching from transmit

[Mike Fanning]

Don, your question is valid but I’m afraid I don’t have a good answer.  I 
honestly don’t know if this is a recent occurrence or if it has always been 
there because I have practically no run time on the KPA100 since I built it.  I 
have put the KDSP2 in bypass and that does fix the problem, as long as I am not 
running full QSK.  In other words, if I add 10ms or more worth of t-r delay, I 
don’t hear the popping with the KDSP2 bypassed.  The receiver will pop if t-r 
delay is set to zero, but that’s probably par for the course.  I have not done 
any sniffing around on the diodes, but that will be next on my to do list after 
Field Day.  Thank you again for your help, and please let me know if you have 
any other suggestions or insight.

73,
Mike, K4GU


On Jun 10, 2015, at 6:36 AM, Don Wilhelm  wrote:

> Mike,
> 
> With the blue toroids, you do have the updated KPA100.  Can I assume that 
> this problem is a recent occurrence rather than a problem that has always 
> been there?
> 
> Yes, removing and jumpering out the KDSP2 will likely stop it (or just try 
> putting it in bypass), but that is not the source of the real problem, it is 
> just the source of the 'pop'.
> I would suggest digging into the KPA100 a bit.  Lay the KPA100 on its 'back' 
> on a book or box to the right of the K2, remove the shield and make the diode 
> voltage measurements.  Hopefully that will reveal an anomaly.
> 
> 73,
> Don W3FPR
> 
> 
> On 6/10/2015 12:45 AM, Mike Fanning wrote:
>> Thanks for the quick reply Don!  I checked the 8R setting and it was indeed 
>> set to hold (and is set there again after toggling it to make sure).  I do 
>> have the KDSP2 option with the KPA100, but after peeling off the right side 
>> panel I see two baby blue toroids.  The K2 is serial number is 5882 and it 
>> was purchased in December 2006.  The KPA100 was bought at Dayton in 2009.  I 
>> think it took me another year to get around to building it, so it was 
>> probably buttoned up about 5 years ago and has been the backup/receive only 
>> rig since doing all the alignment checks.  This will be the first time I 
>> have really done any transmitting with it since adding the KPA100 (I’ll make 
>> sure to revisit the PA screws as instructed).  You have given me something 
>> else to check though - I need to pull the KDSP2 and see if that affects the 
>> problem.  I’m wondering if there were other upgrades to either the K2 or 
>> KDSP2 that might affect this as well?
>> 
>> 
> 
> 
> 

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Re: [Elecraft] K2 noise on receiver when switching from transmit

[Don Wilhelm]

Mike,

With the blue toroids, you do have the updated KPA100.  Can I assume 
that this problem is a recent occurrence rather than a problem that has 
always been there?


Yes, removing and jumpering out the KDSP2 will likely stop it (or just 
try putting it in bypass), but that is not the source of the real 
problem, it is just the source of the 'pop'.
I would suggest digging into the KPA100 a bit.  Lay the KPA100 on its 
'back' on a book or box to the right of the K2, remove the shield and 
make the diode voltage measurements.  Hopefully that will reveal an anomaly.


73,
Don W3FPR


On 6/10/2015 12:45 AM, Mike Fanning wrote:

Thanks for the quick reply Don!  I checked the 8R setting and it was indeed set 
to hold (and is set there again after toggling it to make sure).  I do have the 
KDSP2 option with the KPA100, but after peeling off the right side panel I see 
two baby blue toroids.  The K2 is serial number is 5882 and it was purchased in 
December 2006.  The KPA100 was bought at Dayton in 2009.  I think it took me 
another year to get around to building it, so it was probably buttoned up about 
5 years ago and has been the backup/receive only rig since doing all the 
alignment checks.  This will be the first time I have really done any 
transmitting with it since adding the KPA100 (I’ll make sure to revisit the PA 
screws as instructed).  You have given me something else to check though - I 
need to pull the KDSP2 and see if that affects the problem.  I’m wondering if 
there were other upgrades to either the K2 or KDSP2 that might affect this as 
well?





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Re: [Elecraft] K2 noise on receiver when switching from transmit

[Mike Fanning]

Thanks for the quick reply Don!  I checked the 8R setting and it was indeed set 
to hold (and is set there again after toggling it to make sure).  I do have the 
KDSP2 option with the KPA100, but after peeling off the right side panel I see 
two baby blue toroids.  The K2 is serial number is 5882 and it was purchased in 
December 2006.  The KPA100 was bought at Dayton in 2009.  I think it took me 
another year to get around to building it, so it was probably buttoned up about 
5 years ago and has been the backup/receive only rig since doing all the 
alignment checks.  This will be the first time I have really done any 
transmitting with it since adding the KPA100 (I’ll make sure to revisit the PA 
screws as instructed).  You have given me something else to check though - I 
need to pull the KDSP2 and see if that affects the problem.  I’m wondering if 
there were other upgrades to either the K2 or KDSP2 that might affect this as 
well?

Anyway, thanks for the lead and please let me know if you have any other ideas.

73,
Mike, K4GU


On Jun 9, 2015, at 10:52 PM, Don Wilhelm  wrote:

> Mike,
> 
> I am curious to hear just how long ago that "some time ago" really is.
> 
> The first thing to check is the setting of 8R - it should be set to HOLD with 
> the KPA100 installed.  To check, go in the menu to T-R, edit the parameter 
> and then tap DISPLAY.  If 8R was already set to HOLD, you will see 'nor' and 
> you will have to tap DISPLAY again to set it back to HOLD.  OTOH, if you see 
> HOLD when you tap DISPLAY the first time, it had been set to 'nor' - when you 
> see HOLD, tap the menu button twice to exit.
> 
> There was a time when such pops could occur on some K2s that were equipped 
> with both the KDSP2 and the KPA100.
> The real source was never discovered other than it was caused by some 
> transition in the KPA100 T/R switch and related to the unmute timing in the 
> KDSP2.
> 
> That has not occurred in K2s that have the upgraded KPA100.  So check your 
> KPA100 - remove the right side panel and look between the shield and the 
> board.
> If you see two toroids with blue cores, it has been upgraded, but if you see 
> toroids with red cores, order the KPA100UPKT and do the upgrade.
> 
> 73,
> Don W3FPR
> 
> On 6/9/2015 11:13 PM, Mike Fanning wrote:
>> Hi all,
>> I have a K2 that I built some time ago that I added the KPA100 to at a later 
>> time.  I don’t have more than 10 minutes worth of run time on the KPA100 and 
>> I’m putting a dress rehearsal together for Field Day in a couple of weeks.  
>> I noticed tonight that when I am running more than about 10 Watts (enough to 
>> kick the KPA100 on) that I get a nasty pop on the receiver whenever I come 
>> from transmit to receive mode.  Changing the tx-rx delay doesn’t affect the 
>> noise, and whenever I back the power down so that the KPA100 is not engaged, 
>> the problem goes away.  Any suggestions as to what might be going on?  It 
>> will be really tiring to listen to the receiver in this mode for 24 hours at 
>> FD…
>> 
>> 
> 
> 

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Re: [Elecraft] K2 noise on receiver when switching from transmit

[Don Wilhelm]

Mike,

I am curious to hear just how long ago that "some time ago" really is.

The first thing to check is the setting of 8R - it should be set to HOLD 
with the KPA100 installed.  To check, go in the menu to T-R, edit the 
parameter and then tap DISPLAY.  If 8R was already set to HOLD, you will 
see 'nor' and you will have to tap DISPLAY again to set it back to 
HOLD.  OTOH, if you see HOLD when you tap DISPLAY the first time, it had 
been set to 'nor' - when you see HOLD, tap the menu button twice to exit.


There was a time when such pops could occur on some K2s that were 
equipped with both the KDSP2 and the KPA100.
The real source was never discovered other than it was caused by some 
transition in the KPA100 T/R switch and related to the unmute timing in 
the KDSP2.


That has not occurred in K2s that have the upgraded KPA100.  So check 
your KPA100 - remove the right side panel and look between the shield 
and the board.
If you see two toroids with blue cores, it has been upgraded, but if you 
see toroids with red cores, order the KPA100UPKT and do the upgrade.


73,
Don W3FPR

On 6/9/2015 11:13 PM, Mike Fanning wrote:

Hi all,
I have a K2 that I built some time ago that I added the KPA100 to at a later 
time.  I don’t have more than 10 minutes worth of run time on the KPA100 and 
I’m putting a dress rehearsal together for Field Day in a couple of weeks.  I 
noticed tonight that when I am running more than about 10 Watts (enough to kick 
the KPA100 on) that I get a nasty pop on the receiver whenever I come from 
transmit to receive mode.  Changing the tx-rx delay doesn’t affect the noise, 
and whenever I back the power down so that the KPA100 is not engaged, the 
problem goes away.  Any suggestions as to what might be going on?  It will be 
really tiring to listen to the receiver in this mode for 24 hours at FD…




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[Elecraft] K2 noise on receiver when switching from transmit

[Mike Fanning]

Hi all,
I have a K2 that I built some time ago that I added the KPA100 to at a later 
time.  I don’t have more than 10 minutes worth of run time on the KPA100 and 
I’m putting a dress rehearsal together for Field Day in a couple of weeks.  I 
noticed tonight that when I am running more than about 10 Watts (enough to kick 
the KPA100 on) that I get a nasty pop on the receiver whenever I come from 
transmit to receive mode.  Changing the tx-rx delay doesn’t affect the noise, 
and whenever I back the power down so that the KPA100 is not engaged, the 
problem goes away.  Any suggestions as to what might be going on?  It will be 
really tiring to listen to the receiver in this mode for 24 hours at FD…

Thanks for any light anyone can shed.

73,
Mike, K4GU
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[Elecraft] K2 Noise on 160m

[Jimithy66]

Thanks to all that responded to my K2 problem and thanks for the Tips
Sverre, LA3ZA.
I had done a simple tone adjustment and probably messed up the filters
because the
receive frequency shifts when filter 3 and 4 are selected. After that is
corrected I
 will re-visit the noise problem.

Thanks again Gary, Don, Sverre, and the K9 that responded.

See you in the QRP ARCI 160m 6 hour sprint Wed. evening (in the US).

73/  Jim  / W1FMR




























*Message: 4Date: Mon, 25 Nov 2013 19:01:16 +From: Gary McKelvie
>To:
elecraft@mailman.qth.net Subject: Re: [Elecraft]
K2 Signal to Noise on 160m ?Message-ID:
<43498680-08c7-4f61-b779-0871815fa...@btinternet.com
<43498680-08c7-4f61-b779-0871815fa...@btinternet.com>>Content-Type:
text/plain;   charset=us-asciiThank you to Sverre for the link to a
very interesting and useful web page. 73 Gary G7USCSent from my iPhone> On
24 Nov 2013, at 20:56, "Sverre Holm (LA3ZA)" > wrote:>> You don't give so much information here about how
you did the sidetone pitch> adjustment, but it is easy to mess up things if
you do that without> adjusting filters also.>> See item 3 in the list of
'Elecraft K2 do's and don'ts'>
http://la3za.blogspot.no/2011/09/elecraft-k2-dos-and-donts.html

Jimithy66 wrote>> This a used K2 and I adjusted the STP (Sidetone Pitch)>>
to my liking and wonder if that messed something up>> or is the K2 noisy on
160m ?>*

*Sidetone frequency:* Don't be tempted to adjust the sidetone frequency if
you want it higher or lower in pitch (Menu, sidetone P menu). Many radios
allow this and the K2's menu gives the impression that it is
straightforward to do so. The flip side of the coin is that all the filter
settings (XFIL) and the audio filter (KAF2) also need to be readjusted,
otherwise the filters will not match the new sidetone.
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Re: [Elecraft] K2 noise blanker question

[Don Wilhelm]

Ron,

Yes, there is a simple test.  Turn on the Preamp, do not connect an 
antenna, and tap the case of Q21 with something metallic (like a 
screwdriver).  You will hear clicks along with bursts of sound because 
the screwdriver is acting as an antenna (it is important to distinguish 
between the two).  When you turn on the NB, the clicks should diminish.

Remember that the KNB2 responds to impulse noise only (like automotive 
ignition noise or nearby lightning static), it will not make any 
difference for noise that has a slower rise time, like atmospheric noise 
or other forms of wideband noise.

The way the KNB2 works is to "punch a hole" in the received signal path 
- it "blanks" the signal path for a duration selected by the capacitor 
time constant.  If the time constant is too long, it can create 
significant distortion in the received signal.  Some have doubled the 
value of C11 (solder an additional .001 uF across its leads) and 
reported better results, but it really depends on your particular noise 
source.

73,
Don W3FPR

On 9/10/2011 12:36 AM, R Thompson wrote:
> Is there a simple way to check if the noise blanker for the K2 works?  I
> tried to use it tonight but it didn't seem to make any difference.  Then
> I tried turning a switch on a fan on and off, that produced S7 noise
> spikes on the S meter, but the noise blanker didn't seem to make a
> difference.
>
>Ron VE8RT
>
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[Elecraft] K2 noise blanker question

[R Thompson]

Is there a simple way to check if the noise blanker for the K2 works?  I
tried to use it tonight but it didn't seem to make any difference.  Then
I tried turning a switch on a fan on and off, that produced S7 noise
spikes on the S meter, but the noise blanker didn't seem to make a
difference.

  Ron VE8RT

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[Elecraft] K2 Noise Blanker Revisions

[Nidge_(G0NIG)]

I'm in the process of trying to bring an early K2 (serial#653) kicking and 
screaming 
into the 21st Century, I'll also point out that I'm not the original builder 
of this 
radio. 

For a while I've not been overly convinced about the sensitivity and dynamic 
range of this particular example, it hasn't helped matters that along the 
way 
in my investigations I found numerous build errors. 

Today my attention was drawn to the Noise Blanker option.  I downloaded 
the manual and noticed there were some major differences between my 
example and that referenced in the manual.  I have looked through the 
Elecraft website and found the archived manual for the main build but I 
can't find an archived manual for this particular example of Noise Blanker. 

I'm lucky in that I have a friend very local to me who is in the process of 
building a K2 and so this morning I had the opertuinity to try his more 
recent 
noise blanker board in my K2.  WHAT A DIFFERENCE 

I would guestimate that there was a 25-30dB increase in performance when his 
noise blanker was installed. 

The biggest visual differences between the two boards are: 

My older example has variable capacitors for C3 and C5. 
Pins 3 and 4 of U3 are shorted together 
L1 and L2 are grey torroids, L1 having 13winding and 
L2 having 14 windings 
L3 is marked with brownish orangey paint and has 15 windings. 

I'm hoping someone maybe able to point me to an archived manual 
for this earlier version of the noise blanker so I can assertain if it is 
reworkable or whether a newer revision should be purchased. 

Regards 

Nidge (G0NIG) 

IO93dv 


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Re: [Elecraft] K2 Noise Blanker Part

[C L Jonkers]

Excellent response to building/parts questions is available at 
supp...@elecraft.com. 

73
Neil  NJ6L
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Re: [Elecraft] K2 Noise Blanker Part?

[Dave Sergeant]

.0068uF is 6.8nF. That capacitor labelled 6n8 is the right one (ignore 
the J63, which refer to the tolerance etc).

73 Dave G3YMC

On 16 Jul 2011 at 0:44, vicki glover wrote:

> Guys,
> Trying to build K2 Noise Blanker.  Have part in kit labeled 6n8J63. 
> Missing part for C12 (.0068uF Disk or Monolithic Capacitor).  Is
> Elecraft trying to use this 6n8J63 for C12?  I looked up data sheets on
> the 6n8J63 and it is an inductor, ceramic prehaps wire wound.  This
> can't be right?  What gives?  Any ideas?  Hope some of you may have
> information.  


http://www.davesergeant.com

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[Elecraft] K2 Noise Blanker Part?

[vicki glover]

Guys,
Trying to build K2 Noise Blanker.  Have part in kit labeled 6n8J63.  Missing 
part for C12 (.0068uF Disk or Monolithic Capacitor).  Is Elecraft trying to use 
this 6n8J63 for C12?  I looked up data sheets on the 6n8J63 and it is an 
inductor, ceramic prehaps wire wound.  This can't be right?  What gives?  Any 
ideas?  Hope some of you may have information.  Trying to get "Richard" to call 
is very hit or miss!
73
mike-KB3QJA 
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[Elecraft] K2 Noise Blanker Questions

[Nigel (Nidge) Smith]

I'm in the process of trying to bring an early K2 (serial#653) kicking and 
screaming
into the 21st Century, I'll also point out that I'm not the original builder 
of this
radio.

For a while I've not been overly convinced about the sensitivity and dynamic
range of this particular example, it hasn't helped matters that along the 
way
in my investigations I found numerous build errors.

Today my attention was drawn to the Noise Blanker option.  I downloaded
the manual and noticed there were some major differences between my
example and that referenced in the manual.  I have looked through the
Elecraft website and found the archived manual for the main build but I
can't find an archived manual for this particular example of Noise Blanker.

I'm lucky in that I have a friend very local to me who is in the process of
building a K2 and so this morning I had the opertuinity to try his more 
recent
noise blanker board in my K2.  WHAT A DIFFERENCE

I would guestimate that there was a 25-30dB increase in performance when his
noise blanker was installed.

The biggest visual differences between the two boards are:

My older example has variable capacitors for C3 and C5.
Pins 5 and 6 of U3 are shorted together
L1 and L2 are grey torroids, L1 having 13winding and
L2 having 14 windings
L3 is marked with brownish orangey paint and has 15 windings.

I'm hoping someone maybe able to point me to an archived manual
for this earlier version of the noise blanker so I can assertain if it is
reworkable or whether a newer revision should be purchased.

Regards

Nidge (G0NIG)

IO93dv 

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[Elecraft] [K2] Noise Blanker problem

[Brian Denley]

Pat and Don:
Thanks for the tips!!  I will report back.

Brian 
KB1VBF
http://home.comcast.net/~b.denley/index.html
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Re: [Elecraft] [K2] Noise Blanker problem

[Don Wilhelm]

  Brian,

A Not Installed indication for any K2 option indicates a problem with 
either that option's microprocessor or a continuity on the AUXBUS 
signal.  Check the soldering, especially at the KNB2 firmware chip pin 
1, as well as the other pins of the firmware chip.

The other possibilities are the 4 MHz resonator or the firmware chip itself.

73,
Don W3FPR

On 1/29/2011 9:12 PM, Brian Denley wrote:
> I am still getting the Not Installed message with the KNB2.  I have built
> and re-built the board, rewinding L1 and L2 twice and resoldering all the
> joints again.  Resistance  between pins 1 and 6 is way up in the megohm
> range.  What should it be?Any suggestions would be welcome.
> Brian
> KB1VBF
>
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[Elecraft] [K2] Noise Blanker problem

[Brian Denley]

I am still getting the Not Installed message with the KNB2.  I have built 
and re-built the board, rewinding L1 and L2 twice and resoldering all the 
joints again.  Resistance  between pins 1 and 6 is way up in the megohm 
range.  What should it be?Any suggestions would be welcome.
Brian
KB1VBF
http://home.comcast.net/~b.denley/index.html 

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Re: [Elecraft] [K2] Noise Blanker

[Don Wilhelm]

  Doug,

I am not going to really answer your question, but give it some "food 
for thought" - most true Noise Blankers will not work on RF hash (which 
I would interpret as a "frying noise" mainly because it is too 
constant.  If such a constant noise were to be blanked (the IF would be 
interrupted for the duration of the noise), then you would also kill 
reception.  There are some radios with buttons labeled NB that do more 
of a "noise reduction" function rather than full blanking, and may be 
effective for those more constant types of noise.

Yes, the KDSP2 does do Noise Reduction, and does it quite well.  Whether 
it will handle your particular noise is to be determined.  If you can 
find someone with a K2 equipped with the KDSP2, you would want to try it 
at your location to see if it will handle your noise.  If you do borrow, 
you may want to try several of the variety of setting available on the 
KDSP2, so record your friends settings and restore them before you 
return the K2.  Just a note - some users of the KDSP2 do not know that 
the noise reduction parameters can be adjusted, and they just use 
whatever the defaults are.  You may need something different than the 
defaults, so some experimentation may be required.

73,
Don W3FPR

On 10/4/2010 9:00 PM, Douglas Furton wrote:
> I wrote a week or so ago for some advice about testing my K2 noise blanker.  
> From the replies I received (thank you), I now know that my blanker is 
> probably working FB, but isn't well suited to blank the type of noise that 
> plagues my QTH.
>
> So, I would like to ask anyone with the K2 DSP option if any of the noise 
> reduction schemes implemented digitally are good at blotting out the type of 
> I can't seem to get rid of.
>
> The noise I'm complaining about sounds a lot like the type of RF hash one 
> might expect a noise blanker to get.  In fact, I had a FT-450 that swatted 
> this noise to nothing.
>
> I have the K2 audio filter module, but am wondering if the DSP module might 
> improve my situation.
>
> I would appreciate any relies regarding how well the K2 DSP filter works 
> compared to the analog filter.
>
> Doug
> K8EXB
>
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[Elecraft] [K2] Noise Blanker

[Douglas Furton]

I wrote a week or so ago for some advice about testing my K2 noise blanker.  
From the replies I received (thank you), I now know that my blanker is probably 
working FB, but isn't well suited to blank the type of noise that plagues my 
QTH.

So, I would like to ask anyone with the K2 DSP option if any of the noise 
reduction schemes implemented digitally are good at blotting out the type of I 
can't seem to get rid of.  

The noise I'm complaining about sounds a lot like the type of RF hash one might 
expect a noise blanker to get.  In fact, I had a FT-450 that swatted this noise 
to nothing.

I have the K2 audio filter module, but am wondering if the DSP module might 
improve my situation.

I would appreciate any relies regarding how well the K2 DSP filter works 
compared to the analog filter.

Doug
K8EXB


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[Elecraft] K2 noise blanker and sensitivity

[lstavenhagen]

Hi all,
Speaking of the NB, mine is on the way now from Elecraft and I had a quick
question.

I read somewhere a long time ago (perhaps in the archives here of the
reflector) that the NB module reduces the sensitivity of the RX in the K2.
My questions are

- if so, by how much (i.e. is it noticeable)
- is it all the time, or only when the NB is enabled?

Just curious,

Tnx es 73, 
LS
W5QD
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Re: [Elecraft] K2 noise

[Guy Olinger K2AV]

You did not say whether the PREamp was engaged.  Without it, the
internal noise is very low, and SHOULD be there to a mild degree.
WITHOUT the preamp, AGC off, it takes to about noon for moderate noise
audio.  WITH the preamp, AGC off it takes to about 9 oclock for
moderate noise audio.  What I hear I call hiss, not hash.

If you engage the preamp you will normally hear significantly more
noise. This significantly more noise SHOULD be there. It's a preamp,
and a "quiet preamp" is the holy grail.  A good preamp will increase
the noise as you hear it, but it will increase the signal more.

People use widely varying words to describe ""noise"".  Here I would
ask whether you are hearing hash versus hiss.  Hiss sounds smooth but
is noise.  Hash as a noise has edgy or gritty components to it that
are typically related to 60 Hz, 120 hz, or sometimes odd switching
power supply. But on battery, as you describe, I hear only a hiss.

At one point replacing the battery, I did something to the speaker
(twisted it) where something was making contact as the cone vibrated,
which added a hash-sounding element to speaker audio that was not in
phones audio. I was able to twist it out.

I have gotten hash off of a couple power supplies.  Still the best and
quietest is my ancient (20 years?) 3 amp Rak Shak 22-120A which powers
the K2 with a trickle charge float voltage that keeps the battery
topped off when K2 is off and will power 15 watts without complaint.

73, Guy

On Wed, Feb 3, 2010 at 10:06 AM, richard gilley  wrote:
> With so much talk on the K3 noise, AGC etc I thought I would ask if
> the following is normal on a K2.  Or do I have an issue with my build
> 6732.
> This K2 has the KSUB SSB and KPA100 additions.
> With only battery power and ear phone connected; AGC off: AF fully
> clockwise; RF gain fully ccw; cw mode; fltr settings 200,400, or 700.
> any band,  I hear a definite constant, fairly low level, hash.
>
> With RF gail fully clockwise and AF gain fully ccw, no hash is heard
> until AF gain is advanced from 7 o'clock to about 8 o'clock.
>
> Would this be considered normal or do I have another issue to look into?
>
> Best regards
> Dick AD1G
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Re: [Elecraft] K2 noise

[Mike Harris]

Hi Dick,

The KAF2 removes a lot of hf hash from the audio and makes listening 
to SSB much nicer.  An essential module I would say and many prefer 
it over the more fancy and expensive KDSP2.

Regards,

Mike VP8NO

- Original Message - 
From: "richard gilley" 
To: 
Sent: Wednesday, February 03, 2010 12:06 PM
Subject: [Elecraft] K2 noise


> With so much talk on the K3 noise, AGC etc I thought I would ask 
> if
> the following is normal on a K2.  Or do I have an issue with my 
> build
> 6732.
> This K2 has the KSUB SSB and KPA100 additions.
> With only battery power and ear phone connected; AGC off: AF fully
> clockwise; RF gain fully ccw; cw mode; fltr settings 200,400, or 
> 700.
> any band,  I hear a definite constant, fairly low level, hash.
>
> With RF gail fully clockwise and AF gain fully ccw, no hash is 
> heard
> until AF gain is advanced from 7 o'clock to about 8 o'clock.
>
> Would this be considered normal or do I have another issue to look 
> into?
>
> Best regards
> Dick AD1G

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Re: [Elecraft] K2 noise

[Don Wilhelm]

Dick,

That is probably normal - you are hearing the internal receiver noise.  
It should be at a fairly low level - you said it was, but I can't relate 
to your perception of just how low or loud that may be.  If you are 
using very sensitive headphones, it will be apparent at a lower setting 
of the AF Gain than would be heard with less sensitive headphones.
All I can say for certain is that when I am working on a K2, I normally 
plug my computer Line-in cable into the headphone jack (mainly so I can 
see the trace on Spectrogram), and as a result I hear the K2 audio in 
the computer speakers - I can usually hear the internal receiver white 
noise 'hiss' with the AF Gain set somewhere near the 8 o'clock position 
- but I can change that point easily by adjusting the gain control on th 
epowered computer speakers.

You said you had AGC off - and yes AGC can influence how loud the 
internal noise appears to be.

In the K2 (after SN 3000), there is an AGC Threshold pot on the Control 
Board, and the most sensitive setting for that control is at the point 
where activating the AGC does not *substantially* reduce that internal 
receiver noise.  It will reduce the internal noise a bit, and that exact 
threshold setting will vary from K2 to K2 - the initial 3.80 volt 
setting is not a "one size fits all" setting - the manual alludes to the 
fact that it could be refined by saying "but it can be adjusted later to 
suite the operator."  The manual does not further explain how to 
determine that setting.
Be AWARE - the AGC Threshold must be set before adjusting the S-meter, 
and the S-meter must be calibrated after changing the Threshold.  A 
Threshold setting below about 3.65 volts may not allow one to adjust the 
S-meter properly.

73,
Don W3FPR

richard gilley wrote:
> With so much talk on the K3 noise, AGC etc I thought I would ask if  
> the following is normal on a K2.  Or do I have an issue with my build  
> 6732.
> This K2 has the KSUB SSB and KPA100 additions.
> With only battery power and ear phone connected; AGC off: AF fully  
> clockwise; RF gain fully ccw; cw mode; fltr settings 200,400, or 700.  
> any band,  I hear a definite constant, fairly low level, hash.
>
> With RF gail fully clockwise and AF gain fully ccw, no hash is heard  
> until AF gain is advanced from 7 o'clock to about 8 o'clock.
>
> Would this be considered normal or do I have another issue to look into?
>
> Best regards
> Dick AD1G
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[Elecraft] K2 noise

[richard gilley]

With so much talk on the K3 noise, AGC etc I thought I would ask if  
the following is normal on a K2.  Or do I have an issue with my build  
6732.
This K2 has the KSUB SSB and KPA100 additions.
With only battery power and ear phone connected; AGC off: AF fully  
clockwise; RF gain fully ccw; cw mode; fltr settings 200,400, or 700.  
any band,  I hear a definite constant, fairly low level, hash.

With RF gail fully clockwise and AF gain fully ccw, no hash is heard  
until AF gain is advanced from 7 o'clock to about 8 o'clock.

Would this be considered normal or do I have another issue to look into?

Best regards
Dick AD1G
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Re: [Elecraft] K2 Noise Blanker Problem

[David Woolley (E.L)]

Don Wilhelm wrote:
> 
> First do a test to see if your NB is working at all.  Remove the 
> antenna, turn on the Preamp, then tap on the case of Q21 with a 
> screwdriver.  The taps will create impulse noise in the receiver which 

Has it actually been established that the problem noise is impulsive? 
One of the commonest problems with noise blanking is that people don't 
understand that it is only suitable for wideband, impulsive noise.

-- 
David Woolley
"we do not overly restrict the subject matter on the list, and we
encourage postings on a wide range of amateur radio related topics"
List Guidelines 
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Re: [Elecraft] K2 Noise Blanker Problem

[drewko]

The K2 NB works very well with light-dimmer noise. If you have a
light-dimmer to test it the results should be dramatic.

73,
Drew
AF2Z



On Thu, 27 Aug 2009 13:20:22 -0700 (PDT),  Eric WD6DB(lost in noise)
wrote:

>I built my K2 some months back with the KNB2 option.  The noise blanker has 
>never been effective against any type of noise.  The MCU recognizes the 
>blanker, it draws the proper amount of current, but just doesn't seem to do 
>anything.  Before drinking the Kool-Aid (TM) I was pretty much a Kenwood man 
>and was used to ineffective noise blankers so I ended up blowing it off.  I 
>recently built a K1, and the NB in it works FB.  This got me thinking, and 
>besides Elecraft would never release a NB that was useless--it violates the 
>Tao of Elecraft.  Yesterday I built another KNB2 (any excuse) and installed it 
>in my K2.  Same result!  I checked all the solder joints, component values, RF 
>board mods.  It makes no difference whether it is NB1, NB2, HI or LO, the 
>preamp is on or off--nothing.  No change in S-meter reading, no change in 
>audio.  Any ideas, oh mighty brains?  
>
>Thanks, Eric WD6DB(lost in noise)  
>__

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Re: [Elecraft] K2 Noise Blanker Problem

[Don Wilhelm]

Eric,

First do a test to see if your NB is working at all.  Remove the 
antenna, turn on the Preamp, then tap on the case of Q21 with a 
screwdriver.  The taps will create impulse noise in the receiver which 
should be blanked when NB1 or NB2 is turned on.  Be careful to 
differentiate between the clicks from the impulse noise and the rush of 
'antenna/band noise' that happens because the screwdriver shaft can act 
as an antenna.

If you find the NB is responding to that test, but it still does not 
help with your noise source, you can try widening the gate time a bit - 
try adding an additional .001 uF capacitor in parallel with C11 (just 
soleder ti to the solder pads for a test - if that helps, you can either 
leave the parallel cpacitor in place or change C11 to .002 uF.  Other 
values may help as well, so some experimentation may be of help.  If the 
noise gate is widened too much you will begin to notice "holes" on the 
received signal.

73,
Don W3FPR

eric norris wrote:
> I built my K2 some months back with the KNB2 option.  The noise blanker has 
> never been effective against any type of noise.  The MCU recognizes the 
> blanker, it draws the proper amount of current, but just doesn't seem to do 
> anything.  Before drinking the Kool-Aid (TM) I was pretty much a Kenwood man 
> and was used to ineffective noise blankers so I ended up blowing it off.  I 
> recently built a K1, and the NB in it works FB.  This got me thinking, and 
> besides Elecraft would never release a NB that was useless--it violates the 
> Tao of Elecraft.  Yesterday I built another KNB2 (any excuse) and installed 
> it in my K2.  Same result!  I checked all the solder joints, component 
> values, RF board mods.  It makes no difference whether it is NB1, NB2, HI or 
> LO, the preamp is on or off--nothing.  No change in S-meter reading, no 
> change in audio.  Any ideas, oh mighty brains?  
>
> Thanks, Eric WD6DB(lost in noise)  
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[Elecraft] K2 Noise Blanker Problem

[eric norris]

I built my K2 some months back with the KNB2 option.  The noise blanker has 
never been effective against any type of noise.  The MCU recognizes the 
blanker, it draws the proper amount of current, but just doesn't seem to do 
anything.  Before drinking the Kool-Aid (TM) I was pretty much a Kenwood man 
and was used to ineffective noise blankers so I ended up blowing it off.  I 
recently built a K1, and the NB in it works FB.  This got me thinking, and 
besides Elecraft would never release a NB that was useless--it violates the Tao 
of Elecraft.  Yesterday I built another KNB2 (any excuse) and installed it in 
my K2.  Same result!  I checked all the solder joints, component values, RF 
board mods.  It makes no difference whether it is NB1, NB2, HI or LO, the 
preamp is on or off--nothing.  No change in S-meter reading, no change in 
audio.  Any ideas, oh mighty brains?  

Thanks, Eric WD6DB(lost in noise)  
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[Elecraft] K2 Noise Blanker Problem

[eric norris]

I built my K2 some months back with the KNB2 option.  The noise blanker has 
never been effective against any type of noise.  The MCU recognizes the 
blanker, it draws the proper amount of current, but just doesn't seem to do 
anything.  Before drinking the Kool-Aid (TM) I was pretty much a Kenwood man 
and was used to ineffective noise blankers so I ended up blowing it off.  I 
recently built a K1, and the NB in it works FB.  This got me thinking, and 
besides Elecraft would never release a NB that was useless--it violates the Tao 
of Elecraft.  Yesterday I built another KNB2 (any excuse) and installed it in 
my K2.  Same result!  I checked all the solder joints, component values, RF 
board mods.  It makes no difference whether it is NB1, NB2, HI or LO, the 
preamp is on or off--nothing.  No change in S-meter reading, no change in 
audio.  Any ideas, oh mighty brains?  

Thanks, Eric WD6DB(lost in noise)  
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[Elecraft] K2 Noise Blanker Problem

[eric norris]

I built my K2 some months back with the KNB2 option.  The noise blanker has 
never been effective against any type of noise.  The MCU recognizes the 
blanker, it draws the proper amount of current, but just doesn't seem to do 
anything.  Before drinking the Kool-Aid (TM) I was pretty much a Kenwood man 
and was used to ineffective noise blankers so I ended up blowing it off.  I 
recently built a K1, and the NB in it works FB.  This got me thinking, and 
besides Elecraft would never release a NB that was useless--it violates the Tao 
of Elecraft.  Yesterday I built another KNB2 (any excuse) and installed it in 
my K2.  Same result!  I checked all the solder joints, component values, RF 
board mods.  It makes no difference whether it is NB1, NB2, HI or LO, the 
preamp is on or off--nothing.  No change in S-meter reading, no change in 
audio.  Any ideas, oh mighty brains?  

Thanks, Eric WD6DB(lost in noise)  
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Re: [Elecraft] K2 noise blanker

[ka5oai]

Ron D'Eau Claire wrote:
> 
> One of the early Elecraft customers, Sverre Holm, LA3ZA, put
> together a wonderful page of K2 mods with links to the various documents.
> Check here for info about the KNB2:
> 
> http://www.qslnet.de/member/la3za/K2/modAny.html#KNB2
> 

on that page in the section about:
¤Increase time constants 
http://www.ac6rm.net/mailarchive/html/elecraft-list/2000-10/msg00086.html
http://www.ac6rm.net/mailarchive/html/elecraft-list/2000-10/msg00086.html 
 or here 
http://www.ac6rm.net/mailarchive/html/elecraft-list/2000-08/msg00040.html
http://www.ac6rm.net/mailarchive/html/elecraft-list/2000-08/msg00040.html 
are both 404 links

the gist of it said:
NB1: 10us ->70us
NB2:  70us->500us or 1ms
For electrical noise from motors, electrical fence etc
Increase C11 & C12
G3LUB
but I found no reference to values to change C11 &/or C12 to ???

after some digging I finally found the information here:
http://www.qsl.net/ve3mcf/elecraft_reflect/KNB2_Mods.txt



> Date: Wed, 04 Oct 2000 16:04:31 -0600
> From: Larry East 
> Subject: [Elecraft] Noise Blanker Observations
> 
> Thought I'd add my two (binary) bits worth to the NB discussion:
> 
> I find that my NB is very effective on an annoying popping sound (mostly
> on
> 80M) that I suspect is caused by an electric fence in the area. NB1
> reduces
> it considerably and NB2 removes it completely. I get similar results for
> certain types of static crashes: NB1 is somewhat effective and NB2 is very
> effective. However, neither seems to be too effective against electrical
> noise from drill motors, etc.
> 
> Back in August a couple of folks posted notes that they had increased C12
> on the NB board by a factor of 10 to 20 (thus increasing the blanking gate
> width to around 1-2 milliseconds) and got much better blanking of
> electrical noise. So I decided to give that a try.
> 
> Increasing C12 to 0.1uF definitely resulted in better attenuation (with
> NB2
> selected) of some types of electrical and atmospheric noise. However, it
> resulted in a rather raspy sounding CW signals. Backing off to 0.047uF
> worked just about as well on noise and did not produce any noticeable
> effects on signals.
> 
> As a result, I have made the following mod to my NB board:
> 
> 1. Changed C11 from 0.001uF to 0.0068uF (using the original C12 cap) to
> give an NB1 blanking pulse width of 65-70 us (instead of 10 us).
> 
> 2. Changed C12 from 0.0068uF to 0.047uF to give an NB2 blanking pulse
> width
> of around 500 us (instead of 70 us).
> 
> Seems to be a good overall compromise for the types of noise that I hear.
> Your results may vary.
> 
> 72/73,
> Larry W1HUE/7
> 


the root page was this one:
http://www.qsl.net/ve3mcf/elecraft_reflect/index.html#k2modas

maybe the above info will save someone else some time searching for the
info.


-
73 & GB
KA5OAI
Sam Morgan
-- 
View this message in context: 
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Sent from the Elecraft mailing list archive at Nabble.com.

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Re: [Elecraft] K2 noise blanker

[Brett Gazdzinski]

I did this mod last night.
I did not notice much if any difference.
I have to try the screwdriver on the transistor test Don told me about.

Since they fixed the streetlight, I don't have much noise, but have found 
noise that sounds
very like ignition noise from a car, with no impact from the NB on it.

No big deal, since I don't have a lot of noise (now).

Brett
N2DTS

- Original Message - 
From: "Joe Planisky" 
To: "Brett Gazdzinski" 
Cc: 
Sent: Sunday, March 01, 2009 6:03 PM
Subject: Re: [Elecraft] K2 noise blanker


> Hi Brett,
>
> Last summer, I had similar questions about the KNB2 in my K2.  In my 
> case, a neighbor had put up a new electric fence and I was getting QRM  in 
> the form of a pulse every second.  The unmodified KNB2 seemed to  have 
> little to no effect on the noise.  In fact, I questioned whether  it was 
> working at all.  A 'scrape test' (connecting a wire to the  antenna 
> connector and scraping it on some metal surface in the shack  to generate 
> static) indicated that it was indeed working.
>
> The modification described here
>
> http://www.dl7maj.de/KNB2-Mod.pdf
>
> seemed to improve the situation.  After making the mod described, the 
> KNB2 would partially take out the electric fence noise using the LEVEL 
> LOW threshold.  Not perfect, but better than it was.
>
> You can read the original thread by searching the list archives for  the 
> topic "[K2] KNB2 vs. electric fence" that started on August 3, 2008.
>
> 73
> --
> Joe KB8AP
>
>
> On Mar 1, 2009, at 2:18 PM, Brett Gazdzinski wrote:
>
>> I have tried it on various types of noises, some which sounded like  auto
>> ignition noise, I think someone had something running without  resistor 
>> wires
>> or plugs, strong and weak signals, no change.
>> I did have a bad street light out front of my house, the reason I  got 
>> the
>> NB, but they fixed it before I got the noise blanker.
>>
>> The main reason I asked was there seems to be no degradation of  signals 
>> with
>> the NB on at any setting.
>> On most rigs, you can hear a difference, and where its adjustable,  it 
>> makes
>> things sound really bad when you turn it up. The pro 3 is like that.
>>
>> On the K2, I have been unable to detect it doing anything at all,  any 
>> mode,
>> any noise, although the noise level I usually have is not bad.
>>
>> Thanks for the replies,
>> Brett
>> N2DTS
>> 

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Re: [Elecraft] k2 noise blanker

[Don Wilhelm]

Brett,

To induce a noise that your KNB2 *should* blank, turn on the preamp and 
tap on Q21 with a metal screwdriver - the clicks should disappear with 
the NB on, which will tell you that your KNB2 is working.

If the noise blankiing is not effective with the particular noise you 
are dealing with, you can try widening the gate pulse by placing an 
additional capacitor in parallel with C11.  I would suggest .001 for 
starters, but increase that to whatever your noise source demands.  BUT, 
consider that an increased gate time will cut wider "holes" on your 
received signal, so there is a compromise between a gate time that 
defeats the noise and good receive audio - if the audio distortion is 
too great, then back off on the added capacitance value.

73,
Don W3FPR

Brett Gazdzinski wrote:
> I have the noise blanker in my K2, and I have yet to find a noise it does 
> anything with.
> It seems to have no impact at all on the receiver, no matter what settings.
>
> I did remove the bypass jumper, but it does not act like it
>
> Is it supposed to be noticeable at all with it on?
>
> Brett
>   
>
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Re: [Elecraft] K2 noise blanker

[Ron D'Eau Claire]

IMX with the K2 Noise Blanker there's little or no degradation of normal
signals. However, it can produce intermod noise when strong signals are
present. After all, it does "punch holes" in the signal where the noise
pulses would normally be. That action makes the noise blanker a mixer as
well which will produce artifacts. Some of them are recognizable as such.
Some will merely sound like excess QRN. (That's why the NB has a switch. One
doesn't want it on unless it needs to be on :-) Even so, I've not
experienced significant intermod issues with the KNB2 but I don't live close
to any high powered stations either. 

There are several technical articles on the Elecraft site that might give
you some ideas. One of the early Elecraft customers, Sverre Holm, LA3ZA, put
together a wonderful page of K2 mods with links to the various documents.
Check here for info about the KNB2:

http://www.qslnet.de/member/la3za/K2/modAny.html#KNB2

I've seen some references to various ways to "test" your noise blanker over
time. I didn't explore them because I had a test of my own: I own a lamp
with a cheap dimmer. The KNB2 kills the racket completely when it must be
on. Fortunately, I also own the lamp and can turn it off! 

Also might post a query to "supp...@elecraft.com" 

73,

Ron AC7AC

-Original Message-

I have tried it on various types of noises, some which sounded like auto 
ignition noise, I think someone had something running without resistor wires

or plugs, strong and weak signals, no change.
I did have a bad street light out front of my house, the reason I got the 
NB, but they fixed it before I got the noise blanker.

The main reason I asked was there seems to be no degradation of signals with

the NB on at any setting.
On most rigs, you can hear a difference, and where its adjustable, it makes 
things sound really bad when you turn it up. The pro 3 is like that.

On the K2, I have been unable to detect it doing anything at all, any mode, 
any noise, although the noise level I usually have is not bad.

Thanks for the replies,
Brett
N2DTS 

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Re: [Elecraft] K2 noise blanker

[K2ZR]

Perhaps there's a comment from Elecraft on the K2's Noise Blanker
Dick, K2ZR/4

Brett Gazdzinski wrote:

>Joe,
>I will try this, thanks!
>
>Brett
>N2DTS
>
>- Original Message - 
>From: "Joe Planisky" 
>To: "Brett Gazdzinski" 
>Cc: 
>Sent: Sunday, March 01, 2009 6:03 PM
>Subject: Re: [Elecraft] K2 noise blanker
>
>
>  
>
>>Hi Brett,
>>
>>Last summer, I had similar questions about the KNB2 in my K2.  In my  
>>case, a neighbor had put up a new electric fence and I was getting QRM  
>>in the form of a pulse every second.  The unmodified KNB2 seemed to  
>>have little to no effect on the noise.  In fact, I questioned whether  
>>it was working at all.  A 'scrape test' (connecting a wire to the  
>>antenna connector and scraping it on some metal surface in the shack  
>>to generate static) indicated that it was indeed working.
>>
>>The modification described here
>>
>>http://www.dl7maj.de/KNB2-Mod.pdf
>>
>>seemed to improve the situation.  After making the mod described, the  
>>KNB2 would partially take out the electric fence noise using the LEVEL  
>>LOW threshold.  Not perfect, but better than it was.
>>
>>You can read the original thread by searching the list archives for  
>>the topic "[K2] KNB2 vs. electric fence" that started on August 3, 2008.
>>
>>73
>>--
>>Joe KB8AP
>>
>>
>>On Mar 1, 2009, at 2:18 PM, Brett Gazdzinski wrote:
>>
>>
>>
>>>I have tried it on various types of noises, some which sounded like  
>>>auto
>>>ignition noise, I think someone had something running without  
>>>resistor wires
>>>or plugs, strong and weak signals, no change.
>>>I did have a bad street light out front of my house, the reason I  
>>>got the
>>>NB, but they fixed it before I got the noise blanker.
>>>
>>>The main reason I asked was there seems to be no degradation of  
>>>signals with
>>>the NB on at any setting.
>>>On most rigs, you can hear a difference, and where its adjustable,  
>>>it makes
>>>things sound really bad when you turn it up. The pro 3 is like that.
>>>
>>>On the K2, I have been unable to detect it doing anything at all,  
>>>any mode,
>>>any noise, although the noise level I usually have is not bad.
>>>
>>>Thanks for the replies,
>>>Brett
>>>N2DTS
>>>
>>>  
>>>
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>
>  
>
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Re: [Elecraft] K2 noise blanker

[Brett Gazdzinski]

Joe,
I will try this, thanks!

Brett
N2DTS

- Original Message - 
From: "Joe Planisky" 
To: "Brett Gazdzinski" 
Cc: 
Sent: Sunday, March 01, 2009 6:03 PM
Subject: Re: [Elecraft] K2 noise blanker


> Hi Brett,
> 
> Last summer, I had similar questions about the KNB2 in my K2.  In my  
> case, a neighbor had put up a new electric fence and I was getting QRM  
> in the form of a pulse every second.  The unmodified KNB2 seemed to  
> have little to no effect on the noise.  In fact, I questioned whether  
> it was working at all.  A 'scrape test' (connecting a wire to the  
> antenna connector and scraping it on some metal surface in the shack  
> to generate static) indicated that it was indeed working.
> 
> The modification described here
> 
> http://www.dl7maj.de/KNB2-Mod.pdf
> 
> seemed to improve the situation.  After making the mod described, the  
> KNB2 would partially take out the electric fence noise using the LEVEL  
> LOW threshold.  Not perfect, but better than it was.
> 
> You can read the original thread by searching the list archives for  
> the topic "[K2] KNB2 vs. electric fence" that started on August 3, 2008.
> 
> 73
> --
> Joe KB8AP
> 
> 
> On Mar 1, 2009, at 2:18 PM, Brett Gazdzinski wrote:
> 
>> I have tried it on various types of noises, some which sounded like  
>> auto
>> ignition noise, I think someone had something running without  
>> resistor wires
>> or plugs, strong and weak signals, no change.
>> I did have a bad street light out front of my house, the reason I  
>> got the
>> NB, but they fixed it before I got the noise blanker.
>>
>> The main reason I asked was there seems to be no degradation of  
>> signals with
>> the NB on at any setting.
>> On most rigs, you can hear a difference, and where its adjustable,  
>> it makes
>> things sound really bad when you turn it up. The pro 3 is like that.
>>
>> On the K2, I have been unable to detect it doing anything at all,  
>> any mode,
>> any noise, although the noise level I usually have is not bad.
>>
>> Thanks for the replies,
>> Brett
>> N2DTS
>>
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Re: [Elecraft] K2 noise blanker

[Joe Planisky]

Hi Brett,

Last summer, I had similar questions about the KNB2 in my K2.  In my  
case, a neighbor had put up a new electric fence and I was getting QRM  
in the form of a pulse every second.  The unmodified KNB2 seemed to  
have little to no effect on the noise.  In fact, I questioned whether  
it was working at all.  A 'scrape test' (connecting a wire to the  
antenna connector and scraping it on some metal surface in the shack  
to generate static) indicated that it was indeed working.

The modification described here

http://www.dl7maj.de/KNB2-Mod.pdf

seemed to improve the situation.  After making the mod described, the  
KNB2 would partially take out the electric fence noise using the LEVEL  
LOW threshold.  Not perfect, but better than it was.

You can read the original thread by searching the list archives for  
the topic "[K2] KNB2 vs. electric fence" that started on August 3, 2008.

73
--
Joe KB8AP


On Mar 1, 2009, at 2:18 PM, Brett Gazdzinski wrote:

> I have tried it on various types of noises, some which sounded like  
> auto
> ignition noise, I think someone had something running without  
> resistor wires
> or plugs, strong and weak signals, no change.
> I did have a bad street light out front of my house, the reason I  
> got the
> NB, but they fixed it before I got the noise blanker.
>
> The main reason I asked was there seems to be no degradation of  
> signals with
> the NB on at any setting.
> On most rigs, you can hear a difference, and where its adjustable,  
> it makes
> things sound really bad when you turn it up. The pro 3 is like that.
>
> On the K2, I have been unable to detect it doing anything at all,  
> any mode,
> any noise, although the noise level I usually have is not bad.
>
> Thanks for the replies,
> Brett
> N2DTS
>
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[Elecraft] K2 noise blanker

[Brett Gazdzinski]

I have tried it on various types of noises, some which sounded like auto 
ignition noise, I think someone had something running without resistor wires 
or plugs, strong and weak signals, no change.
I did have a bad street light out front of my house, the reason I got the 
NB, but they fixed it before I got the noise blanker.

The main reason I asked was there seems to be no degradation of signals with 
the NB on at any setting.
On most rigs, you can hear a difference, and where its adjustable, it makes 
things sound really bad when you turn it up. The pro 3 is like that.

On the K2, I have been unable to detect it doing anything at all, any mode, 
any noise, although the noise level I usually have is not bad.

Thanks for the replies,
Brett
N2DTS 

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Re: [Elecraft] k2 noise blanker

[Sam Morgan]

ron wrote:
> Brett Gazdzinski wrote:
>> I have the noise blanker in my K2, and I have yet to find a noise it does 
>> anything with.
>> It seems to have no impact at all on the receiver, no matter what settings.
>>   
>  
> The noise blanker is effective on man-made noise or automobiles, NOT RF 
> (white noise).
> 
What ever type of powerline noise I have at my home qth,
My Kenwood TS-450's noise blanker eliminates it totally.
The noise blanker in my K2 is totally ineffective on it.

There have been other noises that the K2's NB has been able to quieten, but 
that 
is of no help with my powerline noise problem.

P.S. Yes the power company has tried to find and fix it, so far no luck.
They will be back at it in a few months, when I call them again. The Noise id 
temperature sensitive, when the sun heats something up it kicks in, when the 
night cools down it stops. Moving is not an option.
P.P.S. Yes I have tried locating it, off the ends, with a rotateable dipole, no 
joy.
P.P.S.S. Yes I have used an MFJ-1026 phasing unit, again no joy.

-- 
GB & 73
KA5OAI
Sam Morgan
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Re: [Elecraft] k2 noise blanker

[ron]

Brett Gazdzinski wrote:
> I have the noise blanker in my K2, and I have yet to find a noise it does 
> anything with.
> It seems to have no impact at all on the receiver, no matter what settings.
>   
 
The noise blanker is effective on man-made noise or automobiles, NOT RF 
(white noise).

Ron
wb1hga
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Re: [Elecraft] k2 noise blanker

[Ron D'Eau Claire]

The K2's noise blanker likes lots of signal, even when you select low 
threshold. Sometimes switching the K2's preamp on makes the difference between 
no "blanking" at all and full noise suppression.

Keep in mind that the blanker suppresses high amplitude, short duration pulses 
only, such as you hear on 10 meters from unshielded automobile ignition systems 
or on the lower bands from cheap lamp dimmers. If the noise doesn't make a loud 
"buzz" sound, it probably won't suppress it. 

But those noise types that it does suppress, it normally suppresses very, very 
well if the signals are strong enough.

Ron AC7AC



-Original Message-
From: elecraft-boun...@mailman.qth.net 
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of OE5CSP-Chris
Sent: Sunday, March 01, 2009 12:50 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] k2 noise blanker


Brett,


My K2 noise blanker is not doing a lot but there are a few modifications
around, which can be found in the internet.I haven´t tried them yet...

73, Chris



Brett Gazdzinski wrote:
> 
> I have the noise blanker in my K2, and I have yet to find a noise it does 
> anything with.
> It seems to have no impact at all on the receiver, no matter what
> settings.
> 
> I did remove the bypass jumper, but it does not act like it
> 
> Is it supposed to be noticeable at all with it on?
> 
> Brett
> N2DTS 
> 
> __
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-- 
View this message in context: 
http://n2.nabble.com/k2-noise-blanker-tp2403328p2403783.html
Sent from the Elecraft mailing list archive at Nabble.com.

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Re: [Elecraft] k2 noise blanker

[Joe Vrabel]

Brett Gazdzinski wrote:
> 
> I have the noise blanker in my K2, and I have yet to find a noise it does 
> anything with.
> It seems to have no impact at all on the receiver, no matter what
> settings.
> 
> I did remove the bypass jumper, but it does not act like it
> 
> Is it supposed to be noticeable at all with it on?
> 
> Brett
> N2DTS 
> 
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Re: [Elecraft] k2 noise blanker

[OE5CSP-Chris]

Brett,


My K2 noise blanker is not doing a lot but there are a few modifications
around, which can be found in the internet.I haven´t tried them yet...

73, Chris



Brett Gazdzinski wrote:
> 
> I have the noise blanker in my K2, and I have yet to find a noise it does 
> anything with.
> It seems to have no impact at all on the receiver, no matter what
> settings.
> 
> I did remove the bypass jumper, but it does not act like it
> 
> Is it supposed to be noticeable at all with it on?
> 
> Brett
> N2DTS 
> 
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> 

-- 
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Re: [Elecraft] k2 noise blanker

[James Sarte]

Jack,

On the K3, hold down the NB button until you see the DSP menu.  Rotating VFO
A will change the DSP settings while rotating VFO B will change the IF
settings.  

When I come across power line noise for example, I'll usually set the IF
setting to NAR1 and adjust the DSP setting until the noise usually goes
away.  

73,
James KC2UEE

-Original Message-


I haven't found the setting yet  for the K3 blankers that provide the  
same effect, but it should be there.

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Re: [Elecraft] k2 noise blanker

[James Sarte]

Hi Brett,

I don't have a K2, but I do have a K3.  At first I too thought that my NB
board wasn't working, but after tuning around a few bands, I did find some
electrical hash that the NB removed right away.  

73,
James KC2UEE

-Original Message-
From: elecraft-boun...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Brett Gazdzinski
Sent: Saturday, February 28, 2009 11:23 PM
To: elecraft@mailman.qth.net
Subject: [Elecraft] k2 noise blanker

I have the noise blanker in my K2, and I have yet to find a noise it does 
anything with.
It seems to have no impact at all on the receiver, no matter what settings.

I did remove the bypass jumper, but it does not act like it

Is it supposed to be noticeable at all with it on?

Brett
N2DTS 

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Re: [Elecraft] k2 noise blanker

[Jack Brindle]

The noise blanker on my K2 is _very_ effective at eliminating the  
power-line noise in the area. Many time with it off the noise level is  
around S9 or higher and unless signals are very loud I just can't hear  
them. Turn on the NB, and the noise disappears and I hear signals.  
When I first got the K2 with the NB several years ago I had the same  
questions as you. Then the power-line noise problems started, and I  
quickly found out. I just wish whoever is responsible for the PL noise  
would be just as responsive in getting rid of them...

I haven't found the setting yet  for the K3 blankers that provide the  
same effect, but it should be there.

Keep looking at various periodic noise environments, you will find a  
use for the blanker.


On Feb 28, 2009, at 8:22 PM, Brett Gazdzinski wrote:

> I have the noise blanker in my K2, and I have yet to find a noise it  
> does
> anything with.
> It seems to have no impact at all on the receiver, no matter what  
> settings.
>
> I did remove the bypass jumper, but it does not act like it
>
> Is it supposed to be noticeable at all with it on?
>
> Brett
> N2DTS
>
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-Jack Brindle, W6FB
===


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[Elecraft] k2 noise blanker

[Brett Gazdzinski]

I have the noise blanker in my K2, and I have yet to find a noise it does 
anything with.
It seems to have no impact at all on the receiver, no matter what settings.

I did remove the bypass jumper, but it does not act like it

Is it supposed to be noticeable at all with it on?

Brett
N2DTS 

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Re: [Elecraft] K2 Noise Solved

[Jack Smith]

Don:

I can't find it now, but I remember a column by Robert A. Pease in which 
he left a transistor wrapped around  the business end of a soldering 
iron at 700F over the weekend as an experiment and found that its 
performance specs were still in compliance when he checked it Monday 
morning.


A related issue to tip temperature is that a physically small tip will 
loose too much heat. There's a happy optimum where the tip possesses 
sufficient thermal mass to not cool down when applied to the joint, but 
is sufficiently small for the job.


Jack K8ZOA



A word to potential builders - keep the soldering iron temperature 
greater than 700 deg F (750 is better).  You will not damage anything 
if the soldering temperature is 800 deg F or below *and* the soldering 
time is kept short - contrary to popular belief, damage *will* occur 
with a low iron temperature applied for a long period of time.  Also 
use a small diameter solder so you can control the amount and watch as 
the thru-hole is heated, it will wick a bit of solder into the hole 
when it receives adequate heat, but too much applied solder will mask 
that process and can hide a bad solder joint.


73,
Don W3FPR


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Re: [Elecraft] K2 Noise Solved

[Don Wilhelm]

Don,

I have a strong suspicion that the solder pad did not receive enough 
heat initially.  It can happen that the solder looks nice and shiny, but 
the solder does not have good flow onto the pad.  I have seen that 
condition more times than I would like.  It is the result of too low a 
soldering temperature.


A word to potential builders - keep the soldering iron temperature 
greater than 700 deg F (750 is better).  You will not damage anything if 
the soldering temperature is 800 deg F or below *and* the soldering time 
is kept short - contrary to popular belief, damage *will* occur with a 
low iron temperature applied for a long period of time.  Also use a 
small diameter solder so you can control the amount and watch as the 
thru-hole is heated, it will wick a bit of solder into the hole when it 
receives adequate heat, but too much applied solder will mask that 
process and can hide a bad solder joint.


73,
Don W3FPR

[EMAIL PROTECTED] wrote:
A few weeks back I wrote that I was experiencing  a most unusual noise 
problem. I had hoped that someone else might have had  the same problem and would 
have the answer. This didn't happen.
The  noise was noticeable when the volume control and RF Gain were at minimum 
and  even the antenna disconnected.   
I want to thank Gary,   KI4GGX, who was of great encouragement to me is the 
solving of this problem. He  even suggested I record the noise.  I did and sent 
it to him to hear.
I  finally decided to use the bruit force approach and used a 1000 UF 
capacitor  with one side grounded.
Starting at U9 the audio amp, shorting leads to  ground through the 
capacitor, I discovered the noise was coming in via the  CW side tone path. I traced 
the noise to the input to U 10B pin 5.
Under a  high intensity light and a magnifying glass, all solder pads looked 
clean and  shiny.
Not knowing where else to go, I resoldered all the pins of U10 plus  C36. I 
suspect C36 may have been my problem but all that noise has now gone  away.
Don Webb...KA7L  

  


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[Elecraft] K2 Noise Solved

[DDWEBB]

A few weeks back I wrote that I was experiencing  a most unusual noise 
problem. I had hoped that someone else might have had  the same problem and 
would 
have the answer. This didn't happen.
The  noise was noticeable when the volume control and RF Gain were at minimum 
and  even the antenna disconnected.   
I want to thank Gary,   KI4GGX, who was of great encouragement to me is the 
solving of this problem. He  even suggested I record the noise.  I did and sent 
it to him to hear.
I  finally decided to use the bruit force approach and used a 1000 UF 
capacitor  with one side grounded.
Starting at U9 the audio amp, shorting leads to  ground through the 
capacitor, I discovered the noise was coming in via the  CW side tone path. I 
traced 
the noise to the input to U 10B pin 5.
Under a  high intensity light and a magnifying glass, all solder pads looked 
clean and  shiny.
Not knowing where else to go, I resoldered all the pins of U10 plus  C36. I 
suspect C36 may have been my problem but all that noise has now gone  away.
Don Webb...KA7L  




**Gas prices getting you down? Search AOL Autos for 
fuel-efficient used cars.  
(http://autos.aol.com/used?ncid=aolaut000507)
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Re: [Elecraft] K2 Noise

[KD2JC]

I may have had a similar noise in my K-2 and had finally traced it to running
Ham Radio Deluxe while using an external speaker.  If I shut down HRD the
noise would go away, BUT with HRD on and using the internal speaker on the
K-2 it was not there.  I traced it to computer noise getting into the
speaker because of poor shielding of the external speaker leads.  Hope this
helps: 73 


DDWEBB wrote:
> 
> I am hearing  low level random noise from my K2, 
>  I hear it from speaker or head phones as well and even when volume  and
> RF 
> controls are all CCW and the antenna is disconnected. I even hear it when 
> I am 
> in transmit mode. Any suggestions as to where to start looking. I hate the  
> thought of removing the LM380n from the control board and finding I have a
> bad  
> capacitor some where else.
> Don...KA7L
>  
>  
>  S/N 1175. REV B
> 
> 
> 
> **Get trade secrets for amazing burgers. Watch "Cooking with 
> Tyler Florence" on AOL Food.  
> (http://food.aol.com/tyler-florence?video=4&?NCID=aolfod000302)
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[Elecraft] K2 Noise Blanker & XG1

[Bob Scott]

I have been playing catch up with my K2 (#436) and recently installed  
the A - B mods as well as adding the KAF2 AND KNB2 options.  All was  
well until I added the KNB2 option.  When I added the KNB2 option, I  
noticed that my output levels had dropped.  I then discovered that I  
had forgot to change the resistors on the RF board.


Once that was done, I had improved audio, but the S-meter is reading  
low.  With the KNB2 installed and the pre-amp on, I get about an S3  
when I am tuned to the XG1 generator signal set to 50 microvolts.  If  
I bypass the KNB2 by shorting pins 1 to 6 on J12, I get the full S9  
reading.


I have pulled C8 to isolate the bandpass filter and my S-meter  
readings remain at S3.  Is this normal or might I have a problem with  
the bandpass filter.


Thanks in advance for your help.

73, Bob Scott W4ZY
Woodbridge, VA



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[Elecraft] K2 noise blanker

[wb2srf]

When I first completed the K2 with the noise blanker option and ran some
tests, I also expected to hear more of a difference in backround noise
reduction. Unless it is repetitive pulse noise the blanker has no audible
effect which is good in some respects compared to other receivers like
the Icom 706 noise blanker which can needlessly distort the reception of
strong signals.

The blanker is very effective in eliminating lamp dimmer noise, and once
I heard the difference it put my mind to rest that the circut which I
assembled was working properly.

GL 73,
Bob Johansen WB2SRF Staten Island, NY USA
K2 S/N 5622
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RE: [Elecraft] K2 noise blanker

[Ron D'Eau Claire]

Sometimes turning on the preamplifier makes a world of difference, even when
low threshold is selected. I realize that the preamplifier is not needed on
the lower frequency bands and normally would be turned off to preserve the
dynamic range of the receiver. But this is a case where raising the overall
signal levels above normal helps the  KNB2 to suppress the noise much
better. In my experience it often brings otherwise inaudible stations up to
Q5 copy.

I've not been following the thread. My apologies if others have already
mentioned this. 

Ron AC7AC

-Original Message-
Many thanks for all the suggestions!  Since it is easier and quicker to take
the radio to a dimmer switch than it is to remove the covers and scratch the
top of a transistor, I shall do that first!

I am beginning to think that I was expecting too much from the circuit, and
that being elecraft it would somehow squeeze the laws of physics a bit!

73 Stephen G4SJP 

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[Elecraft] K2 noise blanker

[Stephen Prior]

Many thanks for all the suggestions!  Since it is easier and quicker to take
the radio to a dimmer switch than it is to remove the covers and scratch the
top of a transistor, I shall do that first!

I am beginning to think that I was expecting too much from the circuit, and
that being elecraft it would somehow squeeze the laws of physics a bit!

73 Stephen G4SJP 



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Re: [Elecraft] K2 Noise blanker- is it working?

[Don Wilhelm]

Stephen,

Turn the preamp on and scratch/tap the Q21 case with a metallic object 
(screwdriver) while turning the NB on and off.  If the NB is working, 
you will hear the sharp impulse clicks substantially reduced.


Many types of power line noise are not handled by the KNB2, it is great 
on impulse noise, such as that from an automobile engine (not diesel).  
The KDSP2 does a good job on many other types of noise.


73,
Don W3FPR

Stephen Prior wrote:

I built the noise blanker kit for my K2 s/no. 4905 (I think) a few weeks
back, and I am beginning to wonder if it is working.  I can not tell any
difference between NB1, NB2, whether hi or lo threshold.

It is said that it works against the sort of pulse noise I get here from
power lines occasionally, yet it makes no difference.  Since all the cars in
the family are diesel powered and I am some distance from a quiet country
road, I have not had the opportunity to see whether it works on petrol
engined ignition noise.  My experience with noise blankers in other radios
is that you can usually hear some change when it is switched in, but I
don't.

Am I expecting too much?  Or could there possibly be a fault which would
still pass the rx signal through the noise blanker board and yet stop the
noise blanker working?  Had I not read how good it is supposed to be, and
had I not made it myself, I probably would not be asking the question!

  

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Re: [Elecraft] K2 Noise blanker- is it working?

[Bill W5WVO]

Another good source of in-home switching hash is the ubiquitous external 
low-voltage halogen lamp power supply. In my experience, some of them are 
completely quiet, some of them are anything but. If you have one of the 
latter, though, you probably already know that.  :-)


Bill / W5WVO


[EMAIL PROTECTED] wrote:

The best way I have used to test the effectiveness of noise blanker is
try to use the radio in a house with a common incandescent lamp dimmer
nearby the antenna connection. Use a wire antenna placed near the
lamp or wiring of the dimmer circuit if necessary to increase the
coupled noise.

The power line frequency zero crossing pulse width modulator (severe
contant buzzing sound) of the lamp dimmer noise will be almost
completely supressed if the noise blanker circuit is working properly

GL 73,
Bob Johansen WB2SRF
K2 S/N 5622
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[Elecraft] K2 Noise blanker- is it working?

[wb2srf]

The best way I have used to test the effectiveness of noise blanker is
try to use the radio in a house with a common incandescent lamp dimmer
nearby the antenna connection. Use a wire antenna placed near the lamp or
wiring of the dimmer circuit if necessary to increase the coupled noise.

The power line frequency zero crossing pulse width modulator (severe
contant buzzing sound) of the lamp dimmer noise will be almost completely
supressed if the noise blanker circuit is working properly

GL 73,
Bob Johansen WB2SRF
K2 S/N 5622
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[Elecraft] K2 Noise blanker- is it working?

[Stephen Prior]

I built the noise blanker kit for my K2 s/no. 4905 (I think) a few weeks
back, and I am beginning to wonder if it is working.  I can not tell any
difference between NB1, NB2, whether hi or lo threshold.

It is said that it works against the sort of pulse noise I get here from
power lines occasionally, yet it makes no difference.  Since all the cars in
the family are diesel powered and I am some distance from a quiet country
road, I have not had the opportunity to see whether it works on petrol
engined ignition noise.  My experience with noise blankers in other radios
is that you can usually hear some change when it is switched in, but I
don't.

Am I expecting too much?  Or could there possibly be a fault which would
still pass the rx signal through the noise blanker board and yet stop the
noise blanker working?  Had I not read how good it is supposed to be, and
had I not made it myself, I probably would not be asking the question!

Thanks

73 Stephen G4SJP



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Re: [Elecraft] K2 Noise Blanker performance

[drewko1]

I just installed one in my K2. I tested it by turning on a light
dimmer switch on the other side of the house which generates an S5
noise level on 80m. The K2NB totally eliminated it. 

73,
Drew
AF2Z


On Thu, 03 May 2007 04:02:42 +, you wrote:

>I finished K2 #5665 a few weeks ago and have read the
>discussions about how well the K2NB does or doesn't work.  
>
>I'm in an RV on a bluff on the Oregon Coast and we've just 
>had a thunder storm (with hail) pass over.  The tip of the 
>screwdriver antenna's whip produced a few minutes of  strong 
>precipitation static, similar to ignition noise that the noise blanker 
>TOTALLY eleminated.  
>
>It was a good test for the K2's NB ... for this kind of noise, at 
>least ... and it worked GREAT!
>
>73! Ken Kopp - K0PP
>K2 #5665 - K3#_
>[EMAIL PROTECTED]
>
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[Elecraft] K2 Noise Blanker performance

[Ken Kopp]

I finished K2 #5665 a few weeks ago and have read the
discussions about how well the K2NB does or doesn't work.  

I'm in an RV on a bluff on the Oregon Coast and we've just 
had a thunder storm (with hail) pass over.  The tip of the 
screwdriver antenna's whip produced a few minutes of  strong 
precipitation static, similar to ignition noise that the noise blanker 
TOTALLY eleminated.  

It was a good test for the K2's NB ... for this kind of noise, at 
least ... and it worked GREAT!


73! Ken Kopp - K0PP
K2 #5665 - K3#_
[EMAIL PROTECTED]

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RE: [Elecraft] K2 noise

[Don Wilhelm]

Hans,

That effect can happen if your IF filter alignment is way off.  I suggest
aligning the filters using Spectrogram.  See the information for doing that
on the Builders Resouce section of the Elecraft website or look at the K2
Dial Calibration article on my website http://w3fpr.qrpradio.com .

When you are finished aligning the filters, you can observe the AF content
of an actual received signal with Spectrogram and determine if you still
have a problem.

73,
Don W3FPR

> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] Behalf Of Hans Johansson
> Sent: Wednesday, January 10, 2007 4:34 PM
> To: elecraft@mailman.qth.net
> Subject: [Elecraft] K2 noise
>
>
> I have a problem with my K2. When I am listening to CW-signals
> at my beatnote 700 Hz everything is OK. But when I tune to higher
> or lower pitch it comes noise on the signal.It is more noticeable on
> strong signals than on weak ones. I wonder if anyone have had this
> problem and have any suggestions of solution or is it a shortcoming
> of the K2 ? (Perhaps VCO noise). I have no transformer in the
> neighborhood of the K2.
>
> 73 de  Hans  SM6BGA
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>
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[Elecraft] K2 noise

[Hans Johansson]

I have a problem with my K2. When I am listening to CW-signals
at my beatnote 700 Hz everything is OK. But when I tune to higher
or lower pitch it comes noise on the signal.It is more noticeable on
strong signals than on weak ones. I wonder if anyone have had this
problem and have any suggestions of solution or is it a shortcoming
of the K2 ? (Perhaps VCO noise). I have no transformer in the 
neighborhood of the K2.

73 de  Hans  SM6BGA
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RE: [Elecraft] K2 Noise Blanker Slot as Additional IF Amplifier S tage

[Solosko, Robert B (Bob)]

Dick,
If your filters are adjusted correctly (best done using Spectrogram, as 
others have mentioned), it may be that you're not tuning the CW signal to the 
center of the filter's band pass (usually set to 600Hz). I recently added a CW 
tuning indicator to my K2, and now, once the indicator shows that the CW signal 
is centered at 600HZ, I can switch to any of the much narrower XTAL or DSP 
filters and the signal is always right there. To avoid the slight reduction in 
signal level with the narrowest XTAL filters, I have my narrowest XTAL filter 
set to 300Hz and when needed, then use my narrowest DSP filter, which is set to 
100Hz.

73,

Bob W1SRB

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Lemkes
Sent: Friday, August 11, 2006 10:58 PM
To: elecraft@mailman.qth.net
Subject: [Elecraft] K2 Noise Blanker Slot as Additional IF Amplifier
Stage


Has anyone thought of, or tried modifying the K2 Noise Blanker to be an 
additional K2 IF amplifier stage?

My problem is that when I really, really need the crystal filter, I am 
trying to copy a very weak (but readable) CW signal with adjacent S-9 QRM. 
When I switch in tighter than about 1200 Hz of crystal filtering, I tend to 
lose the target signal due to filter loss. ( Losing the target signal is not 
because the BFOs are not properly calibrated).

  When I use just the DSP filter to block the adjacent S-9 QRM, then I still 
lose the target DX due to AGC "pumping" (without the IF "roofing" filter). 
I'd really like some additional IF gain to compensate for the crystal filter 
loss.

  I would try using the Noise Blanker's U1, MC1350, as the added IF stage, 
and use U3, the Controller's decoded program lines to adjust U1's AGC input 
for front panel gain control.  I could use P1's pin 8, 8R, as power for the 
MC1350 so that it's only active on "receive".

  Any feedback would be appreciated.

  73, Dick, AD7AF

Dick and Marty Lemke
PO Box 1038
Ocean Park, WA 98640
Tel. 360-665-2438
www.lemkestudios.com 

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RE: [Elecraft] K2 Noise Blanker Slot as Additional IF Amplifier Stage

[Steven Pituch]

Hi Dick,
The variable crystal filters in the K2 are very good.  In fact the best I
have ever used.  As Don says, unless you have a bad component, crystal
filtering should be excellent down to about 250 Hz, and the DSP down to 100
Hz before you get a bit of attenuation of signal.  You can even boost the
volume a bit in the DSP adjustments.  I originally had similar problems to
you when I first built the rig  in 1999.  Now I use MixW to check the
filters visually.  You can also use Spectrogram.

Pictures don't lie.  I have some MixW screens shots on my website here.  I
think it would be hard to get these kind of results with most other ham
transceivers.
http://users.ev1.net/~spituch/Steve's%20Page/Radio/RTTY/RTTY.html
>From the photos alone the performance of the filters look phenomenal.

If you adjust the filters while looking at the MixW screen you can get
instant feedback on the adustments you are making and easily adjust the
filters perfectly.  Centering the filters this way is a snap.

One of the reasons for the great popularity of the K2 is that you don't need
to add any filters.

Regards,
Steve, W2MY

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RE: [Elecraft] K2 Noise Blanker Slot as Additional IF Amplifier Stage

[Don Wilhelm]

Dick,

Not an IF amplifier stage, but an added IF filter - check out
http://homepages.nildram.co.uk/%7Ebaker/K2_Overview.html to see if that
might address your stated needs.

If you have filter loss at bandwidths less than 1200 Hz, then I would
conclude that you have something wrong with your filter - the filter
typically does not show attenuation until the bandpass is reduced to less
than 200 Hz.  If you are certain your BFO frequencies are correct (the
filter peak is centered on your sidetone pitch), you should not experience
attenuation at reasonable filter widths - if you do, I would suspect that
you have a bad crystal in the filter.

73,
Don W3FPR


> -Original Message-

>
> Has anyone thought of, or tried modifying the K2 Noise Blanker to be an
> additional K2 IF amplifier stage?
>
> My problem is that when I really, really need the crystal filter, I am
> trying to copy a very weak (but readable) CW signal with adjacent
> S-9 QRM.
> When I switch in tighter than about 1200 Hz of crystal filtering,
> I tend to
> lose the target signal due to filter loss. ( Losing the target
> signal is not
> because the BFOs are not properly calibrated).
>
>   When I use just the DSP filter to block the adjacent S-9 QRM,
> then I still
> lose the target DX due to AGC "pumping" (without the IF "roofing"
> filter).
> I'd really like some additional IF gain to compensate for the
> crystal filter
> loss.
>
>   I would try using the Noise Blanker's U1, MC1350, as the added
> IF stage,
> and use U3, the Controller's decoded program lines to adjust U1's
> AGC input
> for front panel gain control.  I could use P1's pin 8, 8R, as
> power for the
> MC1350 so that it's only active on "receive".
>
>

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[Elecraft] K2 Noise Blanker Slot as Additional IF Amplifier Stage

[Lemkes]

Has anyone thought of, or tried modifying the K2 Noise Blanker to be an 
additional K2 IF amplifier stage?


My problem is that when I really, really need the crystal filter, I am 
trying to copy a very weak (but readable) CW signal with adjacent S-9 QRM. 
When I switch in tighter than about 1200 Hz of crystal filtering, I tend to 
lose the target signal due to filter loss. ( Losing the target signal is not 
because the BFOs are not properly calibrated).


 When I use just the DSP filter to block the adjacent S-9 QRM, then I still 
lose the target DX due to AGC "pumping" (without the IF "roofing" filter). 
I'd really like some additional IF gain to compensate for the crystal filter 
loss.


 I would try using the Noise Blanker's U1, MC1350, as the added IF stage, 
and use U3, the Controller's decoded program lines to adjust U1's AGC input 
for front panel gain control.  I could use P1's pin 8, 8R, as power for the 
MC1350 so that it's only active on "receive".


 Any feedback would be appreciated.

 73, Dick, AD7AF

Dick and Marty Lemke
PO Box 1038
Ocean Park, WA 98640
Tel. 360-665-2438
www.lemkestudios.com 


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Re: [Elecraft] K2 Noise Blanker Problem (Feature?)

[John Reiser]

Hi Harvey,

This is for you.  As I said before on this list, If you are having QRN, try 
turning on the KNB2.  On some types, particularly anoying kind kind that 
sounds like frying bacon, it works superbly.  But it doesn't work for all 
kinds of QRN in my experience.  No noise blanker does.


I always try changing the threshhohd as well.  Most of the time I notice no 
change, but sometimes it makes the difference between being able to copy a 
signal and not.  Of course, this assumes that your KNB2 is correctly built.


73,

John (W2GW)

- Original Message - 
From: "Harvey Howell" <[EMAIL PROTECTED]>
To: "Bob Patten" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>; "Elecraft 
Reflector" ; "Lyle Johnson" <[EMAIL PROTECTED]>

Sent: Sunday, April 09, 2006 8:51 PM
Subject: Re: [Elecraft] K2 Noise Blanker Problem (Feature?)


Hi Bob. I tried switching the NB threshold and it has no effect on the NR 
on my K2 s/n 5022.


Harvey KN6VP

- Original Message - 
From: "Bob Patten" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; "Elecraft Reflector" 
; "Lyle Johnson" <[EMAIL PROTECTED]>

Sent: Sunday, April 09, 2006 10:44 AM
Subject: [Elecraft] K2 Noise Blanker Problem (Feature?)


Hi Gary, I finally discovered what the NB was doing on every other 
threshhold change.  What I had perceived
as a drop in level was actually the DSP Noise Reduction being turned on 
and off.  Each time the NB is switched from
low to high threshhold, the DSP NR is either turned on or off depending 
on its present state.  I guess I should
consider this a bonus, since I only have to push one key (albeit twice) 
for NR instead of pushing Display
and Band+.   Now though, I'm wondering if this behaviour is unique to my 
K2 or if any with both Noise Blanker
and DSP installed exhibit the same?  You said you didn't hear any change 
on yours when cycling NB threshhold, but

did that K2 also have DSP installed?

I'll post this to the list also - maybe someone else can verify whether 
this is unique to mine or common to all...


--
73, Bob Patten, N4BPPlantation, FL

E-Mail: [EMAIL PROTECTED]   Website: http://www.qsl.net/n4bp
QRP ARCI #3412SOC #1ARS #799SMIRK #6625  FISTS #7871

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Re: [Elecraft] K2 Noise Blanker Problem (Feature?)

[Harvey Howell]

Hi Bob. I tried switching the NB threshold and it has no effect on the NR on 
my K2 s/n 5022.


Harvey KN6VP

- Original Message - 
From: "Bob Patten" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; "Elecraft Reflector" ; 
"Lyle Johnson" <[EMAIL PROTECTED]>

Sent: Sunday, April 09, 2006 10:44 AM
Subject: [Elecraft] K2 Noise Blanker Problem (Feature?)


Hi Gary, I finally discovered what the NB was doing on every other 
threshhold change.  What I had perceived
as a drop in level was actually the DSP Noise Reduction being turned on 
and off.  Each time the NB is switched from
low to high threshhold, the DSP NR is either turned on or off depending on 
its present state.  I guess I should
consider this a bonus, since I only have to push one key (albeit twice) 
for NR instead of pushing Display
and Band+.   Now though, I'm wondering if this behaviour is unique to my 
K2 or if any with both Noise Blanker
and DSP installed exhibit the same?  You said you didn't hear any change 
on yours when cycling NB threshhold, but

did that K2 also have DSP installed?

I'll post this to the list also - maybe someone else can verify whether 
this is unique to mine or common to all...


--
73, Bob Patten, N4BPPlantation, FL

E-Mail: [EMAIL PROTECTED]   Website: http://www.qsl.net/n4bp
QRP ARCI #3412SOC #1ARS #799SMIRK #6625  FISTS #7871

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[Elecraft] K2 Noise Blanker Problem (Feature?)

[Bob Patten]

Hi Gary, I finally discovered what the NB was doing on every other 
threshhold change.  What I had perceived
as a drop in level was actually the DSP Noise Reduction being turned on 
and off.  Each time the NB is switched from
low to high threshhold, the DSP NR is either turned on or off depending 
on its present state.  I guess I should
consider this a bonus, since I only have to push one key (albeit twice) 
for NR instead of pushing Display
and Band+.   Now though, I'm wondering if this behaviour is unique to my 
K2 or if any with both Noise Blanker
and DSP installed exhibit the same?  You said you didn't hear any change 
on yours when cycling NB threshhold, but

did that K2 also have DSP installed?

I'll post this to the list also - maybe someone else can verify whether 
this is unique to mine or common to all...


--
73, Bob Patten, N4BPPlantation, FL

E-Mail: [EMAIL PROTECTED]   Website: http://www.qsl.net/n4bp
QRP ARCI #3412SOC #1ARS #799SMIRK #6625  FISTS #7871

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Re: [Elecraft] K2, Noise Gen and Spectrogram

[G3VVT]

James,
 
Sometimes in addition to a noise generator and a PC with a soundcard  running 
Spectrogram you may need to add a 600 ohm 1:1 isolation transformer  between 
the LS output of the K2 and the PC sound card input. Perhaps I was  
unfortunate in that both my PC and a separate laptop had spikes on the  display 
from 
harmonics of the AC power frequency. In the UK we use 50Hz AC power  so that 
was 
present as a very large spike followed by 150Hz and every 100Hz  after that 
through the audio spectrum. With your use of 60Hz AC power in the USA  would 
possibly expect that plus multiples through the audio test range if  afflicted.
 
The use of an audio isolation transformer killed these spikes stone  dead.
 
Don, W3FPR suggested the audio transformers from scrap PC modem cards as a  
possible source of suitable 600 ohm transformers.
 
The Spectrogram program turned out to have other uses for me beyond  checking 
K2s.
Having done a hurried rebuild on a 2m repeater for a semi local repeater  
group, when installed on site the through audio was poor and sounded  muffled. 
With the aid of a VHF noise generator plus my laptop running  Spectrogram was 
able to follow the audio through from the repeater RX audio  output, through 
the 
logic and right up to the TX modulator. Apart from the  normal RX de-emphasis 
and the blocking of the audio below 300Hz in the  logic to remove the 
incoming CTCSS, the audio was correct right the way through  the system.
 
The problem in the end turned out to be the TX modulation pre-emphasis was  
not functioning. No doubt there are many other uses for the Spectrogram 
program,  but on this occasion saved me a lot of time in fault finding on the  
repeater.
 
Bob, G3VVT
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Re: [Elecraft] K2, Noise Gen and Spectrogram

[Matt Osborn]

Your URL seems not to work. I located your page at

http://www.qsl.net/w3fpr/index.htm.

Should the other work as well?

On Mon, 27 Jun 2005 16:00:30 -0400, "W3FPR - Don Wilhelm"
<[EMAIL PROTECTED]> wrote:


>Take a look at the K2 Dial Calibration article on my webpage
>http:/w3fpr.qrpradio.com for the information you seek. 
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Re: [Elecraft] K2, Noise Gen and Spectrogram

[Evert Bakker]

Hello James,

The noise generator and spectrogram will do the job!
Look at the www.n0ss.net webpage and you will find the article and 
downloadable software including instructions!

With me, it worked.

Good luck,

Evert, PA2KW, K2 #4836


James Kern wrote:


I need to set my K2 Filters. After I had changed one of my chips a few years
ago, I know by operating my K2 that the filters are 'off' and need to be
reset. I had forgotten about it until this Field Day when my K2 was promptly
removed from the table when the filter problem was 'found'.  My friend
previously set them originally using a noise generator and spectrogram. How
is this done? Is spectrogram and a noise generator all I need? I just
ordered the Elecraft NG1.. will this suffice along with Spectrogram? Does
someone have a nice written web page or technical archive on using
spectrogram with any kind of noise generator? Thanks!

James, KB2FCV
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RE: [Elecraft] K2, Noise Gen and Spectrogram

[W3FPR - Don Wilhelm]

James,

A noise source (NG1 will do nicely) and Spectrogram are all that is required
(ignoring the cable to connect the K2 to the sound card input).

Take a look at the K2 Dial Calibration article on my webpage
http:/w3fpr.qrpradio.com for the information you seek.  If you want to
bypass all the information contained there about setting the reference
oscillator, just skip to "Step 3, Cal FIL".  There are links to additional
information should you need it.

There is also information on the Elecraft website - look in the Builder's
Resources pages.

73,
Don W3FPR

> -Original Message-
>
> I need to set my K2 Filters. After I had changed one of my chips
> a few years
> ago, I know by operating my K2 that the filters are 'off' and need to be
> reset. I had forgotten about it until this Field Day when my K2
> was promptly
> removed from the table when the filter problem was 'found'.  My friend
> previously set them originally using a noise generator and
> spectrogram. How
> is this done? Is spectrogram and a noise generator all I need? I just
> ordered the Elecraft NG1.. will this suffice along with Spectrogram? Does
> someone have a nice written web page or technical archive on using
> spectrogram with any kind of noise generator? Thanks!
>
>
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[Elecraft] K2, Noise Gen and Spectrogram

[James Kern]

I need to set my K2 Filters. After I had changed one of my chips a few years
ago, I know by operating my K2 that the filters are 'off' and need to be
reset. I had forgotten about it until this Field Day when my K2 was promptly
removed from the table when the filter problem was 'found'.  My friend
previously set them originally using a noise generator and spectrogram. How
is this done? Is spectrogram and a noise generator all I need? I just
ordered the Elecraft NG1.. will this suffice along with Spectrogram? Does
someone have a nice written web page or technical archive on using
spectrogram with any kind of noise generator? Thanks!
 
James, KB2FCV
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RE: [Elecraft] K2 Noise Blanker Modifications

[Sverre Holm]

It works now, so I think it is just the usual qsl.net problems. This is why
I have mirrored my mods list on qslnet.de .
 
Try  <http://www.qslnet.de/la3za/K2/mod.html>
http://www.qslnet.de/la3za/K2/mod.html under General mods and KNB2.
 
 
73

Sverre
LA3ZA
http://www.qsl.net/la3za/
  


  _  

From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] 
Sent: 17. november 2004 02:21
To: [EMAIL PROTECTED]; elecraft@mailman.qth.net
Subject: Re: [Elecraft] K2 Noise Blanker Modifications



Hi Sverre,
 
The link to VE3MCF for the mod to increase KNB2 time constant does not seem
to work anymore. Any other source of the mod details for suggested values
for C11/C12?
 
Regards,
Bob, G3VVT

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Re: [Elecraft] K2 Noise Blanker Modifications

[G3VVT]

Hi Sverre,
 
The link to VE3MCF for the mod to increase KNB2 time  constant does not seem 
to work anymore. Any other source of the mod  details for suggested values for 
C11/C12?
 
Regards,
Bob, G3VVT
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RE: [Elecraft] K2 Noise Blanker Modifications

[Sverre Holm]

Did you get a reply to your question? 

In case you did not, there were some noise blanker mods for pulse widths a
long time ago. They can also be found on the K2 Mods list, see
http://www.qslnet.de/la3za/K2/mod.html under General mods and KNB2.

73

Sverre
LA3ZA
http://www.qsl.net/la3za/
 

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Ralph McClintock
Sent: 9. november 2004 11:56
To: elecraft@mailman.qth.net
Subject: [Elecraft] K2 Noise Blanker Modifications

Hello,
 Does anyone have any ideas about level and pulse width modifications for
the K2 Noise Blanker. My problem is neighbors electric fences and corrals.
They were built with aluminum, copper and steel wire intermixed and have
over 300 twisted connections. I have replaced the old solenoid type pulser
with a solid state unit. The pulsing is not even touched by the KNB2 in any
configuration eventhough they are about 40db over 9. I can tell the NB2/LWR
position is working but does not do anywhere near what is required. On
160-40 my primary bands of interest it's really bad. 
Tnx & 73's,
Ralph   W1ZK Vermont
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[Elecraft] K2 Noise Blanker Modifications

[Ralph McClintock]

Hello,
 Does anyone have any ideas about level and pulse width modifications for the 
K2 Noise Blanker. My problem is neighbors electric fences and corrals. They 
were built with aluminum, copper and steel wire intermixed and have over 300 
twisted connections. I have replaced the old solenoid type pulser with a solid 
state unit. The pulsing is not even touched by the KNB2 in any configuration 
eventhough they are about 40db over 9. I can tell the NB2/LWR position is 
working but does not do anywhere near what is required. On 160-40 my primary 
bands of interest it's really bad. 
Tnx & 73's,
Ralph   W1ZK Vermont
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