Re: [Elecraft] CW rise time setting

[E.H. Russell]

In computer space 4ms is an eternity. I do wonder what is going on there. And 
also hope the K4 fixes it. Thanks again for the scope shot.

 

Ed / w2rf

 

 

 

From: Bob Wilson, N6TV  
Sent: Friday, June 12, 2020 10:37 AM
To: Elecraft Reflector 
Cc: E.H. Russell 
Subject: Re: [Elecraft] CW rise time setting

 

The plot in the QST review of the K3S shows the delay between "key closure" 
(the KEY jack of K3S) and RF out.  My plot shows the delay between "amp relay 
closure" (the KEY OUT jack of K3S) and RF, which is more critical.

 

Most folks assume there will be no delay between KEY closure and KEY OUT 
closure, but there is an extra delay (of about 5 ms, minimum) in the K3S.  The 
same applies to PTT IN closure and KEY OUT closure; that is, there is an 
unexplained fixed 5 ms delay in the K3S, probably due to slow firmware logic 
testing for TX Inhibit or an intentional enforcement of some minimum delay in 
RF output.

 

Most radios close KEY OUT immediately upon key closure of either the KEY jack 
or the PTT IN jack.  The K3 does not; it "hesitates" before closing KEY OUT.

 

I'm also hoping the K4 will eliminate this unusual behavior.




73,

Bob, N6TV

 

On Fri, Jun 12, 2020 at 3:23 AM E.H. Russell mailto:e...@qrv.com> > wrote:

Bob,

 

Thanks for the scope shot and info. I compared the waveform to the QST K3S 
review, which seems to show a little over 10ms before RF appears. Is this 
because they used different settings?

 

Will be interesting to see how the new radio CW looks in time and frequency 
domains. Also how the turnaround latency is managed.

 

Tks,

73 Ed w2rf

 

 

 

From: Bob Wilson, N6TV mailto:n...@arrl.net> > 
Sent: Thursday, June 11, 2020 2:05 PM
To: Elecraft Reflector mailto:Elecraft@mailman.qth.net> >
Cc: E.H. Russell mailto:e...@qrv.com> >
Subject: Re: [Elecraft] CW rise time setting

 

On Mon, Jun 8, 2020 at 12:31 PM E.H. Russell mailto:e...@qrv.com> > wrote:

I suppose shaping of the curve corners removes harmonics introduced by the 
abrupt transitions, allowing an accelerated ramp inbetween. But does this 
really reduce the total rise time to 2.5ms? It seems that the softening process 
must take some time. Wish I had a K3 here to scope against other radios. 
Anything published out there?

 

Ed,

 

Per your request, I am publishing this scope screen capture which plots the CW 
rise time in my K3 with the KSYN3A synthesizer upgrade.  It's about 4 ms from 0 
RF to full RF (2 ms per horizontal division):

 

https://www.kkn.net/~n6tv/N6TV_K3_Ser_1494_FW_05.64_TX_DLY_8_CW_QRQ_OFF.png

 

The vertical markers are there to illustrate that CONFIG:TX DLY nor 008  
provides only about 6 ms of RF delay after "KEY OUT" goes to ground, not 8 ms, 
and there is jitter in that delay as well (not shown).  If CW QRQ mode is 
enabled, the delay drops to about 4.6 ms and the TX DLY setting is completely 
ignored.

 

This was discussed here two years ago.  See this post for suggestions on how to 
avoid hot-switching a non-Elecraft amplifier driven by a K3 or K3S:

 

http://elecraft.365791.n2.nabble.com/Default-K3-transmit-delay-may-be-too-short-for-slow-QRO-amplifiers-td7641779.html
  

 

73,

Bob, N6TV

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[Elecraft] CW rise time setting

[Andy Durbin]

"Most folks assume there will be no delay between KEY closure and KEY OUT 
closure, but there is an extra delay (of about 5 ms, minimum) in the K3S."

I suppose I'm not in the "most folks" group.  I measured this delay when 
investigating the keying characterisitcs of my  Kenwood TS-590S.  Key down to 
amplifier relay closure was 2 ms for the configuration under test.  RF started 
rising about 14 ms after key closure.

73,
Andy k3wyc
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Re: [Elecraft] CW rise time setting

[Bob Wilson, N6TV]

The plot in the *QST* review of the K3S shows the delay between "key
closure" (the KEY jack of K3S) and RF out.  My plot shows the delay between
"amp relay closure" (the KEY OUT jack of K3S) and RF, which is more
critical.

Most folks assume there will be no delay between KEY closure and KEY OUT
closure, but there is an extra delay (of about 5 ms, minimum) in the K3S.
The same applies to PTT IN closure and KEY OUT closure; that is, there is
an unexplained fixed 5 ms delay in the K3S, probably due to slow firmware
logic testing for TX Inhibit or an intentional enforcement of some minimum
delay in RF output.

Most radios close KEY OUT immediately upon key closure of either the KEY
jack or the PTT IN jack.  The K3 does not; it "hesitates" before closing
KEY OUT.

I'm also hoping the K4 will eliminate this unusual behavior.

73,
Bob, N6TV

On Fri, Jun 12, 2020 at 3:23 AM E.H. Russell  wrote:

> Bob,
>
>
>
> Thanks for the scope shot and info. I compared the waveform to the QST K3S
> review, which seems to show a little over 10ms before RF appears. Is this
> because they used different settings?
>
>
>
> Will be interesting to see how the new radio CW looks in time and
> frequency domains. Also how the turnaround latency is managed.
>
>
>
> Tks,
>
> 73 Ed w2rf
>
>
>
>
>
>
>
> *From:* Bob Wilson, N6TV 
> *Sent:* Thursday, June 11, 2020 2:05 PM
> *To:* Elecraft Reflector 
> *Cc:* E.H. Russell 
> *Subject:* Re: [Elecraft] CW rise time setting
>
>
>
> On Mon, Jun 8, 2020 at 12:31 PM E.H. Russell  wrote:
>
> I suppose shaping of the curve corners removes harmonics introduced by the
> abrupt transitions, allowing an accelerated ramp inbetween. But does this
> really reduce the total rise time to 2.5ms? It seems that the softening
> process must take some time. Wish I had a K3 here to scope against other
> radios. Anything published out there?
>
>
>
> Ed,
>
>
>
> Per your request, I am publishing this scope screen capture which plots
> the CW rise time in my K3 with the KSYN3A synthesizer upgrade.  It's about
> 4 ms from 0 RF to full RF (2 ms per horizontal division):
>
>
>
> https://www.kkn.net/~n6tv/N6TV_K3_Ser_1494_FW_05.64_TX_DLY_8_CW_QRQ_OFF.png
>
>
>
> The vertical markers are there to illustrate that *CONFIG:TX DLY nor 008*
> provides only about *6 ms* of RF delay after "KEY OUT" goes to ground,
> not 8 ms, and there is jitter in that delay as well (not shown).  If CW QRQ
> mode is enabled, the delay drops to about 4.6 ms and the TX DLY setting is
> completely ignored.
>
>
>
> This was discussed here two years ago.  See this post for suggestions on
> how to avoid hot-switching a non-Elecraft amplifier driven by a K3 or K3S:
>
>
>
>
> http://elecraft.365791.n2.nabble.com/Default-K3-transmit-delay-may-be-too-short-for-slow-QRO-amplifiers-td7641779.html
>
>
>
>
> 73,
>
> Bob, N6TV
>
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Re: [Elecraft] CW rise time setting

[E.H. Russell]

Bob,

 

Thanks for the scope shot and info. I compared the waveform to the QST K3S 
review, which seems to show a little over 10ms before RF appears. Is this 
because they used different settings?

 

Will be interesting to see how the new radio CW looks in time and frequency 
domains. Also how the turnaround latency is managed.

 

Tks,

73 Ed w2rf

 

 

 

From: Bob Wilson, N6TV  
Sent: Thursday, June 11, 2020 2:05 PM
To: Elecraft Reflector 
Cc: E.H. Russell 
Subject: Re: [Elecraft] CW rise time setting

 

On Mon, Jun 8, 2020 at 12:31 PM E.H. Russell mailto:e...@qrv.com> > wrote:

I suppose shaping of the curve corners removes harmonics introduced by the 
abrupt transitions, allowing an accelerated ramp inbetween. But does this 
really reduce the total rise time to 2.5ms? It seems that the softening process 
must take some time. Wish I had a K3 here to scope against other radios. 
Anything published out there?

 

Ed,

 

Per your request, I am publishing this scope screen capture which plots the CW 
rise time in my K3 with the KSYN3A synthesizer upgrade.  It's about 4 ms from 0 
RF to full RF (2 ms per horizontal division):

 

https://www.kkn.net/~n6tv/N6TV_K3_Ser_1494_FW_05.64_TX_DLY_8_CW_QRQ_OFF.png

 

The vertical markers are there to illustrate that CONFIG:TX DLY nor 008  
provides only about 6 ms of RF delay after "KEY OUT" goes to ground, not 8 ms, 
and there is jitter in that delay as well (not shown).  If CW QRQ mode is 
enabled, the delay drops to about 4.6 ms and the TX DLY setting is completely 
ignored.

 

This was discussed here two years ago.  See this post for suggestions on how to 
avoid hot-switching a non-Elecraft amplifier driven by a K3 or K3S:

 

http://elecraft.365791.n2.nabble.com/Default-K3-transmit-delay-may-be-too-short-for-slow-QRO-amplifiers-td7641779.html
  

 

73,

Bob, N6TV

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Re: [Elecraft] CW rise time setting

[Bob Wilson, N6TV]

On Mon, Jun 8, 2020 at 12:31 PM E.H. Russell  wrote:

> I suppose shaping of the curve corners removes harmonics introduced by the
> abrupt transitions, allowing an accelerated ramp inbetween. But does this
> really reduce the total rise time to 2.5ms? It seems that the softening
> process must take some time. Wish I had a K3 here to scope against other
> radios. Anything published out there?
>

Ed,

Per your request, I am publishing this scope screen capture which plots the
CW rise time in my K3 with the KSYN3A synthesizer upgrade.  It's about 4 ms
from 0 RF to full RF (2 ms per horizontal division):

https://www.kkn.net/~n6tv/N6TV_K3_Ser_1494_FW_05.64_TX_DLY_8_CW_QRQ_OFF.png


The vertical markers are there to illustrate that *CONFIG:TX DLY nor 008*
provides only about *6 ms* of RF delay after "KEY OUT" goes to ground, not
8 ms, and there is jitter in that delay as well (not shown).  If CW QRQ
mode is enabled, the delay drops to about 4.6 ms and the TX DLY setting is
completely ignored.

This was discussed here two years ago.  See this post for suggestions on
how to avoid hot-switching a non-Elecraft amplifier driven by a K3 or K3S:

http://elecraft.365791.n2.nabble.com/Default-K3-transmit-delay-may-be-too-short-for-slow-QRO-amplifiers-td7641779.html


73,
Bob, N6TV
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Re: [Elecraft] CW rise time setting

[E.H. Russell]

Jim,

 

Interesting results, especially the dramatic difference in the FTDX5000 after 
the firmware update. The K3 looks great. Hopefully the K4 will be at least as 
good.

 

Ed / w2rf

 

 

 

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Jim Brown
Sent: Tuesday, June 9, 2020 3:46 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] CW rise time setting

 

On 6/9/2020 11:07 AM, Al Lorona wrote:

> The reduction in the sideband levels (what some folks here called 'clicks'... 
> not sure that's a good name for this) varies depending on where you measure 
> it, but in general the sidebands will drop anywhere from 0 to 12 dB-- 
> sometimes less, sometimes more--  when you go from 2 msec to 8 msec rise/fall 
> times. For instance, arbitrarily choosing an offset of 500 Hz from the 
> carrier, the sideband drops by 11 dB for the longer rise time. That turns out 
> to be a fairly typical value. And by the way, in general the sigmoid does a 
> better job than a raised cosine.

 

 

 

I've not looked at the math, but I've measured more than a half dozen radios, 
most with variable time constant shaping, and Elecraft with their fixed 
sigmoidal shaping. The data is here.

 

 <http://k9yc.com/P3_Spectrum_Measurements.pdf> 
http://k9yc.com/P3_Spectrum_Measurements.pdf

 

A K3 at 25W (driving a KPA500 to full power) is 50 dB down 230 Hz either side 
of the signal, 60 dB down at 305 Hz. At 40W driving a legal limit tube amp (Ten 
Tec Titan) sidebands at the power amp output are 50 dB down at 235 Hz, 60 dB 
down at 335 Hz.

 

A neighbor's FT1000 Mark V Field was 50 dB down at 665 Hz.

 

Another neighbor's FTDX5000 set for 6 msec was 50 dB down at 410 Hz, 60 dB down 
at 1.05 kHz before the firmware update. It improved to -50 dB at

310 Hz and -60 at 535 Hz after the update.

 

73, Jim K9YC

 

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Re: [Elecraft] CW rise time setting

[Al Lorona]

I used:

1/(1+exp(-x))

where x = the pulse train. I then modulated a 7 MHz carrier with the result 
(although the results don't care what the RF frequency is, of course).

Al  W6LX


>>>Which sigmoid function did you model, Al?

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Re: [Elecraft] CW rise time setting

[Jim Brown]

On 6/9/2020 11:07 AM, Al Lorona wrote:

The reduction in the sideband levels (what some folks here called 'clicks'... 
not sure that's a good name for this) varies depending on where you measure it, 
but in general the sidebands will drop anywhere from 0 to 12 dB-- sometimes 
less, sometimes more--  when you go from 2 msec to 8 msec rise/fall times. For 
instance, arbitrarily choosing an offset of 500 Hz from the carrier, the 
sideband drops by 11 dB for the longer rise time. That turns out to be a fairly 
typical value. And by the way, in general the sigmoid does a better job than a 
raised cosine.




I've not looked at the math, but I've measured more than a half dozen 
radios, most with variable time constant shaping, and Elecraft with 
their fixed sigmoidal shaping. The data is here.


http://k9yc.com/P3_Spectrum_Measurements.pdf

A K3 at 25W (driving a KPA500 to full power) is 50 dB down 230 Hz either 
side of the signal, 60 dB down at 305 Hz. At 40W driving a legal limit 
tube amp (Ten Tec Titan) sidebands at the power amp output are 50 dB 
down at 235 Hz, 60 dB down at 335 Hz.


A neighbor's FT1000 Mark V Field was 50 dB down at 665 Hz.

Another neighbor's FTDX5000 set for 6 msec was 50 dB down at 410 Hz, 60 
dB down at 1.05 kHz before the firmware update. It improved to -50 dB at 
310 Hz and -60 at 535 Hz after the update.


73, Jim K9YC

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Re: [Elecraft] CW rise time setting

[Fred Jensen]

Which sigmoid function did you model, Al?

73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 6/9/2020 11:07 AM, Al Lorona wrote:

I used to think that the rise and fall times of the CW pulse didn't really 
matter much to the sideband levels; I believed that it was more a function of 
the waveshaping, especially at the corners of the pulse.

But I just ran a quick simulation of a pulse train going through both a raised 
cosine and then a sigmoid filter (because those two have been mentioned in this 
thread) and the rise time definitely does affect the pulse sidebands.

The reduction in the sideband levels (what some folks here called 'clicks'... 
not sure that's a good name for this) varies depending on where you measure it, 
but in general the sidebands will drop anywhere from 0 to 12 dB-- sometimes 
less, sometimes more--  when you go from 2 msec to 8 msec rise/fall times. For 
instance, arbitrarily choosing an offset of 500 Hz from the carrier, the 
sideband drops by 11 dB for the longer rise time. That turns out to be a fairly 
typical value. And by the way, in general the sigmoid does a better job than a 
raised cosine.

Arbitrarily defining the occupied bandwidth as the -60 dBc points of the 
spectrum, and using the sigmoid function with an exponent of -1, the bandwidth 
of the rise time = 8 msec pulse is 420 Hz versus 640 Hz for the pulse with 2 
msec rise time. It's not an enormous difference, but it is something.

Anyway, there's another data point for the discussion.

R,

Al  W6LX



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Re: [Elecraft] CW rise time setting

[Al Lorona]

I used to think that the rise and fall times of the CW pulse didn't really 
matter much to the sideband levels; I believed that it was more a function of 
the waveshaping, especially at the corners of the pulse.

But I just ran a quick simulation of a pulse train going through both a raised 
cosine and then a sigmoid filter (because those two have been mentioned in this 
thread) and the rise time definitely does affect the pulse sidebands. 

The reduction in the sideband levels (what some folks here called 'clicks'... 
not sure that's a good name for this) varies depending on where you measure it, 
but in general the sidebands will drop anywhere from 0 to 12 dB-- sometimes 
less, sometimes more--  when you go from 2 msec to 8 msec rise/fall times. For 
instance, arbitrarily choosing an offset of 500 Hz from the carrier, the 
sideband drops by 11 dB for the longer rise time. That turns out to be a fairly 
typical value. And by the way, in general the sigmoid does a better job than a 
raised cosine.

Arbitrarily defining the occupied bandwidth as the -60 dBc points of the 
spectrum, and using the sigmoid function with an exponent of -1, the bandwidth 
of the rise time = 8 msec pulse is 420 Hz versus 640 Hz for the pulse with 2 
msec rise time. It's not an enormous difference, but it is something.

Anyway, there's another data point for the discussion.

R,

Al  W6LX
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Re: [Elecraft] CW rise time setting

[Wayne Burdick]

Drew,

We apply exactly the same shape to the sidetone, mute on/off, and mark/space 
transitions in FSK and PSK modes.

Wayne
N6KR


> On Jun 8, 2020, at 6:54 PM, Drew AF2Z  wrote:
> 
> A little off topic but is the sidetone also shaped or is it just a plain old 
> sine wave?
> 
> Actually, I wouldn't mind having the option to select a sawtooth or 
> squarewave for the sidetone. I'm not sure why but it seems to make sending on 
> a manual key better, prompting the reflexes to be a little crisper maybe...
> 
> 73,
> Drew
> AF2Z
> 
> 
> 
> On 06/08/20 14:38, Wayne Burdick wrote:
>> It’s closer to 4 ms.
>> Wayne
>> N6KR
>> 
>> elecraft.com
>>> On Jun 8, 2020, at 12:32 PM, E.H. Russell  wrote:
>>> 
>>> I suppose shaping of the curve corners removes harmonics introduced by the 
>>> abrupt transitions, allowing an accelerated ramp inbetween. But does this 
>>> really reduce the total rise time to 2.5ms? It seems that the softening 
>>> process must take some time. Wish I had a K3 here to scope against other 
>>> radios. Anything published out there?
>>> 
>>> 
>>> 
>>> Ed / w2rf
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> From: Alan Bloom 
>>> Sent: Monday, June 8, 2020 3:15 PM
>>> To: E.H. Russell 
>>> Cc: 'Elecraft Reflector' 
>>> Subject: Re: [Elecraft] CW rise time setting
>>> 
>>> 
>>> 
>>> In the "good old days" key shaping was done simply by adding a capacitor to 
>>> the key line or equivalent.  That results in an exponential rise and/or 
>>> fall time, which is not optimum, so the time constant had to be set pretty 
>>> slow to avoid key clicks.  Typically 5-10 ms.  10 ms results in "mushy" 
>>> keying, especially at high CW speeds.
>>> 
>>> 
>>> 
>>> Raised-cosine key shaping is close to optimum and is easy to implement with 
>>> a DSP.  It allows faster rise/fall times without key clicks.  I assume 
>>> Elecraft is using something like that.
>>> 
>>> 
>>> 
>>> Alan N1AL
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> On 2020-06-08 12:51, E.H. Russell wrote:
>>> 
>>> I'm used to CW rise times in th 4-7ms range. Is this 2.5ms arrived at by a
>>> different metric? Is the curve added by sigmoidal shaping somehow excluded
>>> from the measurement?
>>> 
>>> 
>>> 
>>> Ed / w2rf
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> -Original Message-
>>> From: elecraft-boun...@mailman.qth.net 
>>> <mailto:elecraft-boun...@mailman.qth.net>  
>>> mailto:elecraft-boun...@mailman.qth.net> 
>>> > On
>>> Behalf Of Richard Stutsman
>>> Sent: Monday, June 8, 2020 1:31 PM
>>> To: David Gilbert mailto:ab7e...@gmail.com> >
>>> Cc: Elecraft Reflector >> <mailto:Elecraft@mailman.qth.net> >
>>> Subject: Re: [Elecraft] CW rise time setting
>>> 
>>> 
>>> 
>>> Yes, I would regard a 2.5 msec rise time (using appropriate sigmoid
>>> 
>>> shaping) to probably be ideal, in which case I would have no desire to
>>> modify or shorten it. I'll bet it will sound even better than a Drake or a
>>> Ten-Tec!
>>> 
>>> 
>>> 
>>> I hereby withdraw my previous request/opinion.
>>> 
>>> 
>>> 
>>> Rick N6IET
>>> 
>>> 
>>> 
>>> On Mon, Jun 8, 2020 at 10:27 AM David Gilbert < <mailto:ab7e...@gmail.com 
>>> <mailto:ab7e...@gmail.com> >
>>> ab7e...@gmail.com <mailto:ab7e...@gmail.com> > wrote:
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> You don't need to generate clicks to have a crisp CW tone.  Elecraft
>>> 
>>> 
>>> 
>>> 
>>> 
>>> uses a pretty much optimally shaped waveform (some version of a cosine
>>> 
>>> 
>>> 
>>> 
>>> 
>>> function) and if I remember correctly the rise time is only about 2.5
>>> 
>>> 
>>> 
>>> 
>>> 
>>> msec, although I could be wrong about that last part.  And while you
>>> 
>>> 
>>> 
>>> 
>>> 
>>> may be careful not 

Re: [Elecraft] CW rise time setting

[Drew AF2Z]

A little off topic but is the sidetone also shaped or is it just a plain 
old sine wave?


Actually, I wouldn't mind having the option to select a sawtooth or 
squarewave for the sidetone. I'm not sure why but it seems to make 
sending on a manual key better, prompting the reflexes to be a little 
crisper maybe...


73,
Drew
AF2Z



On 06/08/20 14:38, Wayne Burdick wrote:

It’s closer to 4 ms.

Wayne
N6KR


elecraft.com


On Jun 8, 2020, at 12:32 PM, E.H. Russell  wrote:

I suppose shaping of the curve corners removes harmonics introduced by the 
abrupt transitions, allowing an accelerated ramp inbetween. But does this 
really reduce the total rise time to 2.5ms? It seems that the softening process 
must take some time. Wish I had a K3 here to scope against other radios. 
Anything published out there?



Ed / w2rf







From: Alan Bloom 
Sent: Monday, June 8, 2020 3:15 PM
To: E.H. Russell 
Cc: 'Elecraft Reflector' 
Subject: Re: [Elecraft] CW rise time setting



In the "good old days" key shaping was done simply by adding a capacitor to the key line 
or equivalent.  That results in an exponential rise and/or fall time, which is not optimum, so the 
time constant had to be set pretty slow to avoid key clicks.  Typically 5-10 ms.  10 ms results in 
"mushy" keying, especially at high CW speeds.



Raised-cosine key shaping is close to optimum and is easy to implement with a 
DSP.  It allows faster rise/fall times without key clicks.  I assume Elecraft 
is using something like that.



Alan N1AL











On 2020-06-08 12:51, E.H. Russell wrote:

I'm used to CW rise times in th 4-7ms range. Is this 2.5ms arrived at by a
different metric? Is the curve added by sigmoidal shaping somehow excluded
from the measurement?



Ed / w2rf







-Original Message-
From: elecraft-boun...@mailman.qth.net <mailto:elecraft-boun...@mailman.qth.net>  
mailto:elecraft-boun...@mailman.qth.net> > On
Behalf Of Richard Stutsman
Sent: Monday, June 8, 2020 1:31 PM
To: David Gilbert mailto:ab7e...@gmail.com> >
Cc: Elecraft Reflector mailto:Elecraft@mailman.qth.net> 
>
Subject: Re: [Elecraft] CW rise time setting



Yes, I would regard a 2.5 msec rise time (using appropriate sigmoid

shaping) to probably be ideal, in which case I would have no desire to
modify or shorten it. I'll bet it will sound even better than a Drake or a
Ten-Tec!



I hereby withdraw my previous request/opinion.



Rick N6IET



On Mon, Jun 8, 2020 at 10:27 AM David Gilbert < <mailto:ab7e...@gmail.com 
<mailto:ab7e...@gmail.com> >
ab7e...@gmail.com <mailto:ab7e...@gmail.com> > wrote:






You don't need to generate clicks to have a crisp CW tone.  Elecraft





uses a pretty much optimally shaped waveform (some version of a cosine





function) and if I remember correctly the rise time is only about 2.5





msec, although I could be wrong about that last part.  And while you





may be careful not to use short rise/fall times when the band is





active, in the past there have been folks on the contesting reflector





who openly admitted they purposely generate clicks by shortening the





rise/fall times to give themselves elbow room.  I will always





appreciate that Elecraft doesn't give those miscreants the means to

pollute the band.





73,





Dave   AB7E






On Mon, Jun 8, 2020 at 9:23 AM Richard Stutsman <

<mailto:rast...@gmail.com <mailto:rast...@gmail.com> > rast...@gmail.com 
<mailto:rast...@gmail.com> > wrote:





I for one would like to have some control over the rise/fall times.









You want the cleanest (narrowest) of CW signals when operating on a





crowded band or in a contest - unless you're a rare DX station. Most





of my operations are 22wpm rag chews on very uncrowded bands. We're





often the only discernible signals on an entire CW band. And





conditions are often noisy with deep QSB. Why not allow those of us





operating in those circumstances to shorten the rise times a bit,





which makes it easier to copy in noisy conditions, when any close-in





clicks or thumps aren't going to bother anybody? Copying a 'soft'





weak CW signal is like trying to read a 'crisp' signal that's an





entire S-unit weaker, IMO.









My TS-590sg let's me do that, and I love it!









Will the K4 sound as good as a Drake T4C? (Just askin'.)









Rick N6IET









N4ZR wrote:









Will the K4 have options for setting CW rise and fall times...?





Hi Pete,





Probably not. We've always been very careful to ensure our rigs





have an exceptional clean, click-free CW signal. (Third-party





testing bears this





out.) Minimizing the bandwidth requires a very specific rise/fall





time





and





a hand-crafted sigmoidal shaping function in DSP.





Colonel Sanders closely guards his fried chick recipe, Mrs. Fields





won't reveal what's in her chocolate-chip cookies, and only

Re: [Elecraft] CW rise time setting

[Wayne Burdick]

It’s closer to 4 ms. 

Wayne
N6KR


elecraft.com

> On Jun 8, 2020, at 12:32 PM, E.H. Russell  wrote:
> 
> I suppose shaping of the curve corners removes harmonics introduced by the 
> abrupt transitions, allowing an accelerated ramp inbetween. But does this 
> really reduce the total rise time to 2.5ms? It seems that the softening 
> process must take some time. Wish I had a K3 here to scope against other 
> radios. Anything published out there?
> 
> 
> 
> Ed / w2rf
> 
> 
> 
> 
> 
> 
> 
> From: Alan Bloom  
> Sent: Monday, June 8, 2020 3:15 PM
> To: E.H. Russell 
> Cc: 'Elecraft Reflector' 
> Subject: Re: [Elecraft] CW rise time setting
> 
> 
> 
> In the "good old days" key shaping was done simply by adding a capacitor to 
> the key line or equivalent.  That results in an exponential rise and/or fall 
> time, which is not optimum, so the time constant had to be set pretty slow to 
> avoid key clicks.  Typically 5-10 ms.  10 ms results in "mushy" keying, 
> especially at high CW speeds.
> 
> 
> 
> Raised-cosine key shaping is close to optimum and is easy to implement with a 
> DSP.  It allows faster rise/fall times without key clicks.  I assume Elecraft 
> is using something like that.
> 
> 
> 
> Alan N1AL
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> On 2020-06-08 12:51, E.H. Russell wrote:
> 
> I'm used to CW rise times in th 4-7ms range. Is this 2.5ms arrived at by a
> different metric? Is the curve added by sigmoidal shaping somehow excluded
> from the measurement?
> 
> 
> 
> Ed / w2rf
> 
> 
> 
> 
> 
> 
> 
> -Original Message-
> From: elecraft-boun...@mailman.qth.net 
> <mailto:elecraft-boun...@mailman.qth.net>   <mailto:elecraft-boun...@mailman.qth.net> > On
> Behalf Of Richard Stutsman
> Sent: Monday, June 8, 2020 1:31 PM
> To: David Gilbert mailto:ab7e...@gmail.com> >
> Cc: Elecraft Reflector  <mailto:Elecraft@mailman.qth.net> >
> Subject: Re: [Elecraft] CW rise time setting
> 
> 
> 
> Yes, I would regard a 2.5 msec rise time (using appropriate sigmoid
> 
> shaping) to probably be ideal, in which case I would have no desire to
> modify or shorten it. I'll bet it will sound even better than a Drake or a
> Ten-Tec!
> 
> 
> 
> I hereby withdraw my previous request/opinion.
> 
> 
> 
> Rick N6IET
> 
> 
> 
> On Mon, Jun 8, 2020 at 10:27 AM David Gilbert < <mailto:ab7e...@gmail.com 
> <mailto:ab7e...@gmail.com> >
> ab7e...@gmail.com <mailto:ab7e...@gmail.com> > wrote:
> 
> 
> 
> 
> 
> 
> You don't need to generate clicks to have a crisp CW tone.  Elecraft
> 
> 
> 
> 
> 
> uses a pretty much optimally shaped waveform (some version of a cosine
> 
> 
> 
> 
> 
> function) and if I remember correctly the rise time is only about 2.5
> 
> 
> 
> 
> 
> msec, although I could be wrong about that last part.  And while you
> 
> 
> 
> 
> 
> may be careful not to use short rise/fall times when the band is
> 
> 
> 
> 
> 
> active, in the past there have been folks on the contesting reflector
> 
> 
> 
> 
> 
> who openly admitted they purposely generate clicks by shortening the
> 
> 
> 
> 
> 
> rise/fall times to give themselves elbow room.  I will always
> 
> 
> 
> 
> 
> appreciate that Elecraft doesn't give those miscreants the means to
> 
> pollute the band.
> 
> 
> 
> 
> 
> 73,
> 
> 
> 
> 
> 
> Dave   AB7E
> 
> 
> 
> 
> 
> 
> On Mon, Jun 8, 2020 at 9:23 AM Richard Stutsman <
> 
> <mailto:rast...@gmail.com <mailto:rast...@gmail.com> > rast...@gmail.com 
> <mailto:rast...@gmail.com> > wrote:
> 
> 
> 
> 
> 
> I for one would like to have some control over the rise/fall times.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> You want the cleanest (narrowest) of CW signals when operating on a
> 
> 
> 
> 
> 
> crowded band or in a contest - unless you're a rare DX station. Most
> 
> 
> 
> 
> 
> of my operations are 22wpm rag chews on very uncrowded bands. We're
> 
> 
> 
> 
> 
> often the only discernible signals on an entire CW band. And
> 
> 
> 
> 
> 
> conditions are often noisy with deep QSB. Why not allow those of us
> 
> 
> 
> 
> 
> operating in those circumstances to shorten the rise times a bit,
> 
> 
> 
> 
> 
> which makes it easier to copy in noisy conditions, when any close-in
> 
> 
> 
> 
> 
> clicks or thumps aren't going to bother anybody? 

Re: [Elecraft] CW rise time setting

[E.H. Russell]

I suppose shaping of the curve corners removes harmonics introduced by the 
abrupt transitions, allowing an accelerated ramp inbetween. But does this 
really reduce the total rise time to 2.5ms? It seems that the softening process 
must take some time. Wish I had a K3 here to scope against other radios. 
Anything published out there?

 

Ed / w2rf

 

 

 

From: Alan Bloom  
Sent: Monday, June 8, 2020 3:15 PM
To: E.H. Russell 
Cc: 'Elecraft Reflector' 
Subject: Re: [Elecraft] CW rise time setting

 

In the "good old days" key shaping was done simply by adding a capacitor to the 
key line or equivalent.  That results in an exponential rise and/or fall time, 
which is not optimum, so the time constant had to be set pretty slow to avoid 
key clicks.  Typically 5-10 ms.  10 ms results in "mushy" keying, especially at 
high CW speeds.

 

Raised-cosine key shaping is close to optimum and is easy to implement with a 
DSP.  It allows faster rise/fall times without key clicks.  I assume Elecraft 
is using something like that.

 

Alan N1AL

 

 

 

 

 

On 2020-06-08 12:51, E.H. Russell wrote:

I'm used to CW rise times in th 4-7ms range. Is this 2.5ms arrived at by a
different metric? Is the curve added by sigmoidal shaping somehow excluded
from the measurement?

 

Ed / w2rf

 

 

 

-Original Message-
From: elecraft-boun...@mailman.qth.net 
<mailto:elecraft-boun...@mailman.qth.net>  mailto:elecraft-boun...@mailman.qth.net> > On
Behalf Of Richard Stutsman
Sent: Monday, June 8, 2020 1:31 PM
To: David Gilbert mailto:ab7e...@gmail.com> >
Cc: Elecraft Reflector mailto:Elecraft@mailman.qth.net> >
Subject: Re: [Elecraft] CW rise time setting

 

Yes, I would regard a 2.5 msec rise time (using appropriate sigmoid

shaping) to probably be ideal, in which case I would have no desire to
modify or shorten it. I'll bet it will sound even better than a Drake or a
Ten-Tec!

 

I hereby withdraw my previous request/opinion.

 

Rick N6IET

 

On Mon, Jun 8, 2020 at 10:27 AM David Gilbert < <mailto:ab7e...@gmail.com 
<mailto:ab7e...@gmail.com> >
ab7e...@gmail.com <mailto:ab7e...@gmail.com> > wrote:

 




You don't need to generate clicks to have a crisp CW tone.  Elecraft





uses a pretty much optimally shaped waveform (some version of a cosine





function) and if I remember correctly the rise time is only about 2.5





msec, although I could be wrong about that last part.  And while you





may be careful not to use short rise/fall times when the band is





active, in the past there have been folks on the contesting reflector





who openly admitted they purposely generate clicks by shortening the





rise/fall times to give themselves elbow room.  I will always





appreciate that Elecraft doesn't give those miscreants the means to

pollute the band.





73,





Dave   AB7E






On Mon, Jun 8, 2020 at 9:23 AM Richard Stutsman <

<mailto:rast...@gmail.com <mailto:rast...@gmail.com> > rast...@gmail.com 
<mailto:rast...@gmail.com> > wrote:





I for one would like to have some control over the rise/fall times.









You want the cleanest (narrowest) of CW signals when operating on a





crowded band or in a contest - unless you're a rare DX station. Most





of my operations are 22wpm rag chews on very uncrowded bands. We're





often the only discernible signals on an entire CW band. And





conditions are often noisy with deep QSB. Why not allow those of us





operating in those circumstances to shorten the rise times a bit,





which makes it easier to copy in noisy conditions, when any close-in





clicks or thumps aren't going to bother anybody? Copying a 'soft'





weak CW signal is like trying to read a 'crisp' signal that's an





entire S-unit weaker, IMO.









My TS-590sg let's me do that, and I love it!









Will the K4 sound as good as a Drake T4C? (Just askin'.)









Rick N6IET









N4ZR wrote:









Will the K4 have options for setting CW rise and fall times...?





Hi Pete,





Probably not. We've always been very careful to ensure our rigs





have an exceptional clean, click-free CW signal. (Third-party





testing bears this





out.) Minimizing the bandwidth requires a very specific rise/fall





time





and





a hand-crafted sigmoidal shaping function in DSP.





Colonel Sanders closely guards his fried chick recipe, Mrs. Fields





won't reveal what's in her chocolate-chip cookies, and only





selected firmware monks--sworn to secrecy--are privy to Elecraft's





keying envelope coefficients :) 73, Wayne N6KR





__





Elecraft mailing list





Home:  <http://mailman.qth.net/mailman/listinfo/elecraft>

http://mailman.qth.net/mailman/listinfo/elecraft




Help:  <http://mailman.qth.net/mmfaq.htm>

http://mailman.qth.net/mmfaq.htm




Post:  <mailto:Ele

Re: [Elecraft] CW rise time setting

[Alan Bloom]

In the "good old days" key shaping was done simply by adding a capacitor
to the key line or equivalent.  That results in an exponential rise
and/or fall time, which is not optimum, so the time constant had to be
set pretty slow to avoid key clicks.  Typically 5-10 ms.  10 ms results
in "mushy" keying, especially at high CW speeds. 

Raised-cosine key shaping is close to optimum and is easy to implement
with a DSP.  It allows faster rise/fall times without key clicks.  I
assume Elecraft is using something like that. 

Alan N1AL 

On 2020-06-08 12:51, E.H. Russell wrote:

> I'm used to CW rise times in th 4-7ms range. Is this 2.5ms arrived at by a
> different metric? Is the curve added by sigmoidal shaping somehow excluded
> from the measurement?
> 
> Ed / w2rf
> 
> -Original Message-
> From: elecraft-boun...@mailman.qth.net  On
> Behalf Of Richard Stutsman
> Sent: Monday, June 8, 2020 1:31 PM
> To: David Gilbert 
> Cc: Elecraft Reflector 
> Subject: Re: [Elecraft] CW rise time setting
> 
> Yes, I would regard a 2.5 msec rise time (using appropriate sigmoid
> 
> shaping) to probably be ideal, in which case I would have no desire to
> modify or shorten it. I'll bet it will sound even better than a Drake or a
> Ten-Tec!
> 
> I hereby withdraw my previous request/opinion.
> 
> Rick N6IET
> 
> On Mon, Jun 8, 2020 at 10:27 AM David Gilbert < <mailto:ab7e...@gmail.com>
> ab7e...@gmail.com> wrote:
> 
>> You don't need to generate clicks to have a crisp CW tone.  Elecraft
> 
>> uses a pretty much optimally shaped waveform (some version of a cosine
> 
>> function) and if I remember correctly the rise time is only about 2.5
> 
>> msec, although I could be wrong about that last part.  And while you
> 
>> may be careful not to use short rise/fall times when the band is
> 
>> active, in the past there have been folks on the contesting reflector
> 
>> who openly admitted they purposely generate clicks by shortening the
> 
>> rise/fall times to give themselves elbow room.  I will always
> 
>> appreciate that Elecraft doesn't give those miscreants the means to
> pollute the band.
> 
>> 73,
> 
>> Dave   AB7E
> 
>> On Mon, Jun 8, 2020 at 9:23 AM Richard Stutsman <
> <mailto:rast...@gmail.com> rast...@gmail.com> wrote:
> 
> I for one would like to have some control over the rise/fall times.

> 

>> You want the cleanest (narrowest) of CW signals when operating on a

>> crowded band or in a contest - unless you're a rare DX station. Most

>> of my operations are 22wpm rag chews on very uncrowded bands. We're

>> often the only discernible signals on an entire CW band. And

>> conditions are often noisy with deep QSB. Why not allow those of us

>> operating in those circumstances to shorten the rise times a bit,

>> which makes it easier to copy in noisy conditions, when any close-in

>> clicks or thumps aren't going to bother anybody? Copying a 'soft'

>> weak CW signal is like trying to read a 'crisp' signal that's an

>> entire S-unit weaker, IMO.

> 

>> My TS-590sg let's me do that, and I love it!

> 

>> Will the K4 sound as good as a Drake T4C? (Just askin'.)

> 

>> Rick N6IET

> 

> N4ZR wrote:

> 

> Will the K4 have options for setting CW rise and fall times...?

> Hi Pete,

> Probably not. We've always been very careful to ensure our rigs

> have an exceptional clean, click-free CW signal. (Third-party

> testing bears this

> out.) Minimizing the bandwidth requires a very specific rise/fall

> time

>> and

> a hand-crafted sigmoidal shaping function in DSP.

> Colonel Sanders closely guards his fried chick recipe, Mrs. Fields

> won't reveal what's in her chocolate-chip cookies, and only

> selected firmware monks--sworn to secrecy--are privy to Elecraft's

> keying envelope coefficients :) 73, Wayne N6KR

>> __

>> Elecraft mailing list

>> Home:  <http://mailman.qth.net/mailman/listinfo/elecraft>
 http://mailman.qth.net/mailman/listinfo/elecraft

>> Help:  <http://mailman.qth.net/mmfaq.htm>
 http://mailman.qth.net/mmfaq.htm

>> Post:  <mailto:Elecraft@mailman.qth.net> mailto:Elecraft@mailman.qth.net

> 

>> This list hosted by:  <http://www.qsl.net> http://www.qsl.net Please help
 support this 

>> email list:  <http://www.qsl.net/donate.html>
 http://www.qsl.net/donate.html Message delivered to 

>> <mailto:ab7e...@gmail.com> ab7e...@gmail.com

> 

__

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Home: 

Re: [Elecraft] CW rise time setting

[E.H. Russell]

I'm used to CW rise times in th 4-7ms range. Is this 2.5ms arrived at by a
different metric? Is the curve added by sigmoidal shaping somehow excluded
from the measurement?

 

Ed / w2rf

 

 

 

-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Richard Stutsman
Sent: Monday, June 8, 2020 1:31 PM
To: David Gilbert 
Cc: Elecraft Reflector 
Subject: Re: [Elecraft] CW rise time setting

 

Yes, I would regard a 2.5 msec rise time (using appropriate sigmoid

shaping) to probably be ideal, in which case I would have no desire to
modify or shorten it. I'll bet it will sound even better than a Drake or a
Ten-Tec!

 

I hereby withdraw my previous request/opinion.

 

Rick N6IET

 

On Mon, Jun 8, 2020 at 10:27 AM David Gilbert < <mailto:ab7e...@gmail.com>
ab7e...@gmail.com> wrote:

 

> You don't need to generate clicks to have a crisp CW tone.  Elecraft 

> uses a pretty much optimally shaped waveform (some version of a cosine 

> function) and if I remember correctly the rise time is only about 2.5 

> msec, although I could be wrong about that last part.  And while you 

> may be careful not to use short rise/fall times when the band is 

> active, in the past there have been folks on the contesting reflector 

> who openly admitted they purposely generate clicks by shortening the 

> rise/fall times to give themselves elbow room.  I will always 

> appreciate that Elecraft doesn't give those miscreants the means to
pollute the band.

> 

> 73,

> Dave   AB7E

> 

> On Mon, Jun 8, 2020 at 9:23 AM Richard Stutsman <
<mailto:rast...@gmail.com> rast...@gmail.com> wrote:

> 

>> I for one would like to have some control over the rise/fall times.

>> 

>> You want the cleanest (narrowest) of CW signals when operating on a 

>> crowded band or in a contest - unless you're a rare DX station. Most 

>> of my operations are 22wpm rag chews on very uncrowded bands. We're 

>> often the only discernible signals on an entire CW band. And 

>> conditions are often noisy with deep QSB. Why not allow those of us 

>> operating in those circumstances to shorten the rise times a bit, 

>> which makes it easier to copy in noisy conditions, when any close-in 

>> clicks or thumps aren't going to bother anybody? Copying a 'soft' 

>> weak CW signal is like trying to read a 'crisp' signal that's an 

>> entire S-unit weaker, IMO.

>> 

>> My TS-590sg let's me do that, and I love it!

>> 

>> Will the K4 sound as good as a Drake T4C? (Just askin'.)

>> 

>> Rick N6IET

>> 

>> > N4ZR wrote:

>> > >

>> > > Will the K4 have options for setting CW rise and fall times...?

>> > Hi Pete,

>> > Probably not. We've always been very careful to ensure our rigs 

>> > have an exceptional clean, click-free CW signal. (Third-party 

>> > testing bears this

>> > out.) Minimizing the bandwidth requires a very specific rise/fall 

>> > time

>> and

>> > a hand-crafted sigmoidal shaping function in DSP.

>> > Colonel Sanders closely guards his fried chick recipe, Mrs. Fields 

>> > won't reveal what's in her chocolate-chip cookies, and only 

>> > selected firmware monks--sworn to secrecy--are privy to Elecraft's 

>> > keying envelope coefficients :) 73, Wayne N6KR

>> __

>> Elecraft mailing list

>> Home:  <http://mailman.qth.net/mailman/listinfo/elecraft>
http://mailman.qth.net/mailman/listinfo/elecraft

>> Help:  <http://mailman.qth.net/mmfaq.htm>
http://mailman.qth.net/mmfaq.htm

>> Post:  <mailto:Elecraft@mailman.qth.net> mailto:Elecraft@mailman.qth.net

>> 

>> This list hosted by:  <http://www.qsl.net> http://www.qsl.net Please help
support this 

>> email list:  <http://www.qsl.net/donate.html>
http://www.qsl.net/donate.html Message delivered to 

>>  <mailto:ab7e...@gmail.com> ab7e...@gmail.com

>> 

> 

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Message delivered to arch...@mail-archive.com 

Re: [Elecraft] CW rise time setting

[Jim Brown]

On 6/8/2020 9:21 AM, Richard Stutsman wrote:

I for one would like to have some control over the rise/fall times.

You want the cleanest (narrowest) of CW signals when operating on a crowded
band or in a contest - unless you're a rare DX station. Most of my
operations are 22wpm rag chews on very uncrowded bands. We're often the
only discernible signals on an entire CW band. And conditions are often
noisy with deep QSB. Why not allow those of us operating in those
circumstances to shorten the rise times a bit, which makes it easier to
copy in noisy conditions,


Because that's not how it works. Keying in all Elecraft rigs since the 
K3 has been carefully shaped for optimum copy AND minimum bandwidth. 
What Elecraft does is FAR superior to those rigs with adjustable rise time.


> My TS-590sg let's me do that, and I love it!

You should ALWAYS run it at the longest rise time setting.

>Will the K4 sound as good as a Drake T4C? (Just askin'.)

Although I worked for Drake doing final test of their first TR3s, I 
can't say that I know what a T4C sounds like. Do you?


73, Jim K9YC
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Message delivered to arch...@mail-archive.com 

Re: [Elecraft] CW rise time setting

[Richard Stutsman]

Yes, I would regard a 2.5 msec rise time (using appropriate sigmoid
shaping) to probably be ideal, in which case I would have no desire to
modify or shorten it. I'll bet it will sound even better than a Drake or a
Ten-Tec!

I hereby withdraw my previous request/opinion.

Rick N6IET

On Mon, Jun 8, 2020 at 10:27 AM David Gilbert  wrote:

> You don't need to generate clicks to have a crisp CW tone.  Elecraft uses
> a pretty much optimally shaped waveform (some version of a cosine function)
> and if I remember correctly the rise time is only about 2.5 msec, although
> I could be wrong about that last part.  And while you may be careful not to
> use short rise/fall times when the band is active, in the past there have
> been folks on the contesting reflector who openly admitted they purposely
> generate clicks by shortening the rise/fall times to give themselves elbow
> room.  I will always appreciate that Elecraft doesn't give those miscreants
> the means to pollute the band.
>
> 73,
> Dave   AB7E
>
> On Mon, Jun 8, 2020 at 9:23 AM Richard Stutsman  wrote:
>
>> I for one would like to have some control over the rise/fall times.
>>
>> You want the cleanest (narrowest) of CW signals when operating on a
>> crowded
>> band or in a contest - unless you're a rare DX station. Most of my
>> operations are 22wpm rag chews on very uncrowded bands. We're often the
>> only discernible signals on an entire CW band. And conditions are often
>> noisy with deep QSB. Why not allow those of us operating in those
>> circumstances to shorten the rise times a bit, which makes it easier to
>> copy in noisy conditions, when any close-in clicks or thumps aren't going
>> to bother anybody? Copying a 'soft' weak CW signal is like trying to read
>> a
>> 'crisp' signal that's an entire S-unit weaker, IMO.
>>
>> My TS-590sg let's me do that, and I love it!
>>
>> Will the K4 sound as good as a Drake T4C? (Just askin'.)
>>
>> Rick N6IET
>>
>> > N4ZR wrote:
>> > >
>> > > Will the K4 have options for setting CW rise and fall times...?
>> > Hi Pete,
>> > Probably not. We've always been very careful to ensure our rigs have an
>> > exceptional clean, click-free CW signal. (Third-party testing bears this
>> > out.) Minimizing the bandwidth requires a very specific rise/fall time
>> and
>> > a hand-crafted sigmoidal shaping function in DSP.
>> > Colonel Sanders closely guards his fried chick recipe, Mrs. Fields won't
>> > reveal what's in her chocolate-chip cookies, and only selected firmware
>> > monks--sworn to secrecy--are privy to Elecraft's keying envelope
>> > coefficients :)
>> > 73,
>> > Wayne
>> > N6KR
>> __
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Re: [Elecraft] CW rise time setting

[David Gilbert]

You don't need to generate clicks to have a crisp CW tone.  Elecraft uses a
pretty much optimally shaped waveform (some version of a cosine function)
and if I remember correctly the rise time is only about 2.5 msec, although
I could be wrong about that last part.  And while you may be careful not to
use short rise/fall times when the band is active, in the past there have
been folks on the contesting reflector who openly admitted they purposely
generate clicks by shortening the rise/fall times to give themselves elbow
room.  I will always appreciate that Elecraft doesn't give those miscreants
the means to pollute the band.

73,
Dave   AB7E

On Mon, Jun 8, 2020 at 9:23 AM Richard Stutsman  wrote:

> I for one would like to have some control over the rise/fall times.
>
> You want the cleanest (narrowest) of CW signals when operating on a crowded
> band or in a contest - unless you're a rare DX station. Most of my
> operations are 22wpm rag chews on very uncrowded bands. We're often the
> only discernible signals on an entire CW band. And conditions are often
> noisy with deep QSB. Why not allow those of us operating in those
> circumstances to shorten the rise times a bit, which makes it easier to
> copy in noisy conditions, when any close-in clicks or thumps aren't going
> to bother anybody? Copying a 'soft' weak CW signal is like trying to read a
> 'crisp' signal that's an entire S-unit weaker, IMO.
>
> My TS-590sg let's me do that, and I love it!
>
> Will the K4 sound as good as a Drake T4C? (Just askin'.)
>
> Rick N6IET
>
> > N4ZR wrote:
> > >
> > > Will the K4 have options for setting CW rise and fall times...?
> > Hi Pete,
> > Probably not. We've always been very careful to ensure our rigs have an
> > exceptional clean, click-free CW signal. (Third-party testing bears this
> > out.) Minimizing the bandwidth requires a very specific rise/fall time
> and
> > a hand-crafted sigmoidal shaping function in DSP.
> > Colonel Sanders closely guards his fried chick recipe, Mrs. Fields won't
> > reveal what's in her chocolate-chip cookies, and only selected firmware
> > monks--sworn to secrecy--are privy to Elecraft's keying envelope
> > coefficients :)
> > 73,
> > Wayne
> > N6KR
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Re: [Elecraft] CW rise time setting

[David Box]

Glad to hear that we can count on the K4 maintaining the excellent CW 
characteristics.  I frequently will look at signals I am receiving 
measuring the transmitted waveform based on what I see on the P3 and it 
never ceases to amaze me about how different brands can be identified 
based on the waveform shape and spectral width, not to mention the 
audible key clicks.


de Dave K5MWR

On 6/7/2020 20:45, Wayne Burdick wrote:

N4ZR wrote:

Will the K4 have options for setting CW rise and fall times...?

Hi Pete,

Probably not. We've always been very careful to ensure our rigs have an 
exceptional clean, click-free CW signal. (Third-party testing bears this out.) 
Minimizing the bandwidth requires a very specific rise/fall time and a 
hand-crafted sigmoidal shaping function in DSP.

Colonel Sanders closely guards his fried chick recipe, Mrs. Fields won't reveal 
what's in her chocolate-chip cookies, and only selected firmware monks--sworn 
to secrecy--are privy to Elecraft's keying envelope coefficients :)

73,
Wayne
N6KR




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[Elecraft] CW rise time setting

[Richard Stutsman]

I for one would like to have some control over the rise/fall times.

You want the cleanest (narrowest) of CW signals when operating on a crowded
band or in a contest - unless you're a rare DX station. Most of my
operations are 22wpm rag chews on very uncrowded bands. We're often the
only discernible signals on an entire CW band. And conditions are often
noisy with deep QSB. Why not allow those of us operating in those
circumstances to shorten the rise times a bit, which makes it easier to
copy in noisy conditions, when any close-in clicks or thumps aren't going
to bother anybody? Copying a 'soft' weak CW signal is like trying to read a
'crisp' signal that's an entire S-unit weaker, IMO.

My TS-590sg let's me do that, and I love it!

Will the K4 sound as good as a Drake T4C? (Just askin'.)

Rick N6IET

> N4ZR wrote:
> >
> > Will the K4 have options for setting CW rise and fall times...?
> Hi Pete,
> Probably not. We've always been very careful to ensure our rigs have an
> exceptional clean, click-free CW signal. (Third-party testing bears this
> out.) Minimizing the bandwidth requires a very specific rise/fall time and
> a hand-crafted sigmoidal shaping function in DSP.
> Colonel Sanders closely guards his fried chick recipe, Mrs. Fields won't
> reveal what's in her chocolate-chip cookies, and only selected firmware
> monks--sworn to secrecy--are privy to Elecraft's keying envelope
> coefficients :)
> 73,
> Wayne
> N6KR
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Re: [Elecraft] CW rise time setting

[N4ZR]

Good!

73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 6/7/2020 9:45 PM, Wayne Burdick wrote:

N4ZR wrote:

Will the K4 have options for setting CW rise and fall times...?

Hi Pete,

Probably not. We've always been very careful to ensure our rigs have an 
exceptional clean, click-free CW signal. (Third-party testing bears this out.) 
Minimizing the bandwidth requires a very specific rise/fall time and a 
hand-crafted sigmoidal shaping function in DSP.

Colonel Sanders closely guards his fried chick recipe, Mrs. Fields won't reveal 
what's in her chocolate-chip cookies, and only selected firmware monks--sworn 
to secrecy--are privy to Elecraft's keying envelope coefficients :)

73,
Wayne
N6KR





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Re: [Elecraft] CW rise time setting

[David Gilbert]

Thank you.  I'd be really disappointed if the keying waveform for the K4
was made adjustable.  I consider the fact that it is not adjustable on my
K3 to be one of its best features.

On Sun, Jun 7, 2020 at 6:49 PM Wayne Burdick  wrote:

> > N4ZR wrote:
> >
> > Will the K4 have options for setting CW rise and fall times...?
>
> Hi Pete,
>
> Probably not. We've always been very careful to ensure our rigs have an
> exceptional clean, click-free CW signal. (Third-party testing bears this
> out.) Minimizing the bandwidth requires a very specific rise/fall time and
> a hand-crafted sigmoidal shaping function in DSP.
>
> Colonel Sanders closely guards his fried chick recipe, Mrs. Fields won't
> reveal what's in her chocolate-chip cookies, and only selected firmware
> monks--sworn to secrecy--are privy to Elecraft's keying envelope
> coefficients :)
>
> 73,
> Wayne
> N6KR
>
>
>
>
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Re: [Elecraft] CW rise time setting

[Bob McGraw K4TAX]

Thanks Wayne for the excellent and exceptional clean keying.  

73
Bob, K4TAX


Sent from my iPhone

> On Jun 7, 2020, at 8:49 PM, Wayne Burdick  wrote:
> 
> 
>> 
>> N4ZR wrote:
>> 
>> Will the K4 have options for setting CW rise and fall times...?
> 
> Hi Pete,
> 
> Probably not. We've always been very careful to ensure our rigs have an 
> exceptional clean, click-free CW signal. (Third-party testing bears this 
> out.) Minimizing the bandwidth requires a very specific rise/fall time and a 
> hand-crafted sigmoidal shaping function in DSP.
> 
> Colonel Sanders closely guards his fried chick recipe, Mrs. Fields won't 
> reveal what's in her chocolate-chip cookies, and only selected firmware 
> monks--sworn to secrecy--are privy to Elecraft's keying envelope coefficients 
> :)
> 
> 73,
> Wayne
> N6KR
> 
> 
> 
> 
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Re: [Elecraft] CW rise time setting

[Wayne Burdick]

> N4ZR wrote:
> 
> Will the K4 have options for setting CW rise and fall times...?

Hi Pete,

Probably not. We've always been very careful to ensure our rigs have an 
exceptional clean, click-free CW signal. (Third-party testing bears this out.) 
Minimizing the bandwidth requires a very specific rise/fall time and a 
hand-crafted sigmoidal shaping function in DSP.

Colonel Sanders closely guards his fried chick recipe, Mrs. Fields won't reveal 
what's in her chocolate-chip cookies, and only selected firmware monks--sworn 
to secrecy--are privy to Elecraft's keying envelope coefficients :)

73,
Wayne
N6KR




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Re: [Elecraft] CW rise time setting

[Fred Jensen]

I really hope the answer is "No."  Rise/Fall times and waveshape of the 
RF envelope should be tailored by the mfr for the best signal, not 
adjustable.


73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 6/7/2020 6:35 PM, N4ZR wrote:
Will the K4 have options for setting CW rise and fall times, not just 
TXDELAY like the K3?




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[Elecraft] CW rise time setting

[N4ZR]

Will the K4 have options for setting CW rise and fall times, not just 
TXDELAY like the K3?


--
73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

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[Elecraft] CW Rise Time?

[John Huffman]

My call - K1ESE - is misinterpreted in CW as - K1EST - when  my keying 
is too soft.  I cured this on my Orion by setting the CW rise/fall time 
from 7ms to 5ms.

I can't find the parameter to set the rise/fall time on my K3.

How do you do that?

73 de K1ESE
John
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Re: [Elecraft] CW Rise Time?

[Paul Christensen]

 My call - K1ESE - is misinterpreted in CW as - K1EST - when  my keying
 is too soft.  I cured this on my Orion by setting the CW rise/fall time
 from 7ms to 5ms. I can't find the parameter to set the rise/fall time on 
 my K3.

John,

I found that in the last K3 F/W release (or perhaps the one just before it), 
the K3's CW rise/fall time is now roughly 2.5 ms compared to the previous 
5-6 ms.  I had to verify my scope settings on another time base to ensure I 
had not misinterpreted the measured result.

That being the case, it seems to me that the K3's CW envelope has gone 
through two evolutionary changes.  The first occurred a while back with a 
hardware fix and that mod is documented on the Elecraft website.  Prior to 
the fix, CW rise was about 8 ms or perhaps a bit longer.  After the hardware 
fix, the rise went to about 5-6 ms.  And now, we seem to be down to about 
2.5 ms.

Whether intentional or not by Elecraft, that is what I now measure on my K3. 
Perhaps this is not representative of other K3s.  Also, I do not detect an 
increase in the amount of keying sidebands with the faster ramping/decay. 
So, the ALC is still preserving the raised cosine function very well.

Long story short -- if Elecraft did in fact accelerate the ramping/decay 
time of the CW envelope down to about 2.5 ms, I can't imagine why anyone 
would want keying any harder and faster than that.  I am very happy with 
what I'm seeing.

Paul, W9AC
 

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Re: [Elecraft] CW Rise Time?

[John Huffman]

Paul -

My K3 SN 2533 is running FW 3.19.  If the rise is 2.5ms, I sure don't 
want to try anything shorter.

On the Orion messing with the weighting didn't solve the problem, just 
the ris/fall time.  I'll set the K3 weighting to .90 and see if that helps.

I wonder if the change in rise to 2.5ms has effected the key line to the 
amp?

Thanks for the info.

73 de K1ESE
John


  My call - K1ESE - is misinterpreted in CW as - K1EST - when  my keying
  is too soft.  I cured this on my Orion by setting the CW rise/fall time
  from 7ms to 5ms. I can't find the parameter to set the rise/fall time on
  my K3.

John,

I found that in the last K3 F/W release (or perhaps the one just before 
it), the K3's CW rise/fall time is now roughly 2.5 ms compared to the 
previous 5-6 ms.  I had to verify my scope settings on another time base 
to ensure I had not misinterpreted the measured result.

  .

Paul, W9AC

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Re: [Elecraft] CW rise time

[Leigh L. Klotz, Jr WA5ZNU]

According to http://www.elecraft.com/K3/k3_app_notes.htm this change was 
phased in Approximately Jan 20, 2008 Approx. s/n 211.  So that sounds 
to me like the current shipping ones are 5ms instead of 8ms.  It also 
alludes to future firmware control enabled by the mod.


Leigh/WA5ZNU

According to my friends and according to MP3 files they have made for me,
the CW note from my K3 serial number 152 sounds fine.  Not as hard as 
my K2

and not too soft.  I see there is a modification to change the rise time
from 8 to 5 milliseconds by installing a different capacitor  at C222 
on the

RF board.  I wonder what value cap is present in currently shipping K3's?
Wonder what people have thought about the change in the CW waveform after
changing this capacitor?

I know there are those who will say if it ain't broke, don't fix it.  But
it's the true Elecraft spirit to make something good even better.

Please answer off list as well as on as I get the reflector in digest 
form

only.  Thanks!

Andy W9NJY
Milwaukee WI


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[Elecraft] CW rise time

[Andrew Catanzaro]

According to my friends and according to MP3 files they have made for me,
the CW note from my K3 serial number 152 sounds fine.  Not as hard as my K2
and not too soft.  I see there is a modification to change the rise time
from 8 to 5 milliseconds by installing a different capacitor  at C222 on the
RF board.  I wonder what value cap is present in currently shipping K3's?
Wonder what people have thought about the change in the CW waveform after
changing this capacitor?

I know there are those who will say if it ain't broke, don't fix it.  But
it's the true Elecraft spirit to make something good even better.

Please answer off list as well as on as I get the reflector in digest form
only.  Thanks!

Andy W9NJY
Milwaukee WI


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Re: [Elecraft] CW rise time mod topic

[John R. Lonigro]

Hi everyone:
I have Thunderbird check for the magic characters K3 in the subject.  
When they are found, those emails are put into a separate folder.  Not 
owning a K3, that makes it easier for me to quickly scan through topics 
that probably aren't of interest to me.  Some folks don't bother to put 
K3 in the subject, although the topic refers to some aspect of that 
radio.  That's OK.  I'm not complaining about that.  However, when 
people start talking about radio mods, it seems imperative to me that 
they mention somewhere, preferably in the subject line, which radio they 
are referring to.  In this case, there are CW mods for both the K2 and 
K3 (and probably K1 and KX1 as well).


This was not meant to be a criticism.  It's just a suggestion to 
possibly prevent unnecessary confusion.


73's,
John AA0VE

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Re: [Elecraft] CW rise time mod topic

[R. Kevin Stover]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

I agree John.

The list moderators have asked, on several occasions, for people to put
the model of elecraft product in the subject line. It was suggested that
doing this would allow people to use the filtering capabilities of their
mail clients to sort through all the mail and stick it in the right spots.

It was also one of the excuses put forward to keep Elecraft from having
forums where it's pretty simple to stick your message in the right spot.
Got a K3 question, stick it in the K3 forum, Couldn't care less about
the K3, don't read the K3 forum.

How hard it it to put K3, K2, K1, KX1 in the subject line? My six year
old granddaughter can do it.


John R. Lonigro wrote:
| Hi everyone:
| I have Thunderbird check for the magic characters K3 in the subject.
| When they are found, those emails are put into a separate folder.  Not
| owning a K3, that makes it easier for me to quickly scan through topics
| that probably aren't of interest to me.  Some folks don't bother to put
| K3 in the subject, although the topic refers to some aspect of that
| radio.  That's OK.  I'm not complaining about that.  However, when
| people start talking about radio mods, it seems imperative to me that
| they mention somewhere, preferably in the subject line, which radio they
| are referring to.  In this case, there are CW mods for both the K2 and
| K3 (and probably K1 and KX1 as well).
|
| This was not meant to be a criticism.  It's just a suggestion to
| possibly prevent unnecessary confusion.
|
| 73's,
| John AA0VE


- --
R. Kevin Stover, ACØH
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Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

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RE: [Elecraft] CW rise time mod

[Ron D'Eau Claire]

While the impact on a receiver might cause clicks to be heard, that's a
failing of the receiver, not the transmitter.

The real issue about the CW keying waveform is the production of sidebands
around the CW signal at the transmitter. All amplitude-modulated signals,
which CW is one type, have sidebands. The only way to prevent them entirely
is to not modulate the signal. Since the rate of the modulation is much less
with CW than it is with a spectrum of voice covering, say, 300 to 3000 Hz,
the sidebands produced by CW keying are much, much smaller than those
produced by voice modulation. 

But that doesn't mean the sidebands produced by CW keying can be ignored,
especially in today's world of very selective receivers that allow signals
to be much closer to each other than in the past. 

Without the sidebands, the CW would be unreadable. It's a question of how
wide the sidebands must be and how the energy is distributed in them to
produce an easy-to-copy signal that is not wider than necessary. 

Easy-to-copy is a value judgment. There are no absolute values.

Exotic computer-controlled keying circuits with linear RF amplifiers have
given designers the ability to control the keying waveform and the energy
distribution in the sidebands to a degree never contemplated only a few
years ago. 

But the underlying question is unchanged: what is the best tradeoff between
bandwidth and readability of a CW signal? 

It's still a judgment call. 

Ron AC7AC


-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]
Sent: Monday, March 31, 2008 9:16 PM
To: [EMAIL PROTECTED]; elecraft@mailman.qth.net
Subject: Re: [Elecraft] CW rise time mod


It's not that 3ms is a lot of time in terms of human scale. But, it is the  
rise time of an electronic pulse. This can have a lot of impact on the 
transient  waveform that results in an audio demodulator - i.e. receiver.
The 
difference is  noticeable enough to make the difference in a crowded band
weak signal 
situation  when the receiving station is differentiating what he hears.
That's 
why a banjo  sounds different than a guitar  or violin.
 
Al WA6VNN
 

+
 
In a message dated 3/29/2008 5:34:22 P.M. Pacific Daylight Time,  
[EMAIL PROTECTED] writes:
People,

8 ms.- 5 ms.= 3 ms., does it  matter in any practical sense?  I would really

like to know who cares,  and why?  Can anyone hear the difference? 
Three-thousanths of a  second?  Not my old brain.

73,
John, W2GW
K3  #384


- Original Message - 
From: Lyle Johnson  [EMAIL PROTECTED]
To: Elecraft Reflector  elecraft@mailman.qth.net
Sent: Saturday, March 29, 2008 5:21  PM
Subject: Re: [Elecraft] CW rise time mod


 Or do Rev A  RF boards have a lower value for C222 than that shown on 
 the
  schematic?

 Early production K3 RF boards have a 1 uF capacitor  instead of a 0.1 
 uF
 capacitor installed at C222.  Yes, the  published schematics show a 0.1 uF

 capacitor.  The effect of the  larger capacitor is to increase the TX 
 waveform rise time to about 8 ms  instead of 5 ms.

 Rev B RF boards have the correct 0.1 uF value  installed.  Sometime 
 during
 Rev A RF board production, the value  installed on the board was changed 
 from 1 uF to 0.1 uF.

  Surface mount ceramic capacitors are not marked with a value, so you
  cannot tell which you have by visual inspection.

 You can  determine if you have a 1 uF rather than a 0.1 uF by:

 1)  Measuring the capacitance if you have a capacitance meter.

 2)  Looking at the Tx output RF envelope on an oscilloscope or 
 station
  monitor scope.  If the fall time and the rise time look very similar in

 duration, you have the 0.1 uF cap. If the rise time is about 50% longer  
 than the fall time, you have the 1 uF capacitor.  You don't need  an 
 oscilloscope with an accurate time base to make this comparative  
 measurement.  If your oscilloscope has a low bandwidth (2 to 10  MHz), use

 the 160 meter band.

 3) If you are concerned  that your unit may have the 1 uF capacitor 
 and you
 have no way to  determine it otherwise, you can just replace it with the 
 0.1 uF part  and sleep better at night :-)

 If you don't change it, you will  not damage anything.  Your K3 will 
 just
 have slightly softer  keying and an upcoming firmware adjustment of the 
 keying time will be  less accurate.

 73,

 Lyle KK7P

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Re: [Elecraft] CW rise time mod

[AJSOENKE]

It's not that 3ms is a lot of time in terms of human scale. But, it is the  
rise time of an electronic pulse. This can have a lot of impact on the 
transient  waveform that results in an audio demodulator - i.e. receiver. The 
difference is  noticeable enough to make the difference in a crowded band weak 
signal 
situation  when the receiving station is differentiating what he hears. That's 
why a banjo  sounds different than a guitar  or violin.
 
Al WA6VNN
 
+
 
In a message dated 3/29/2008 5:34:22 P.M. Pacific Daylight Time,  
[EMAIL PROTECTED] writes:
People,

8 ms.- 5 ms.= 3 ms., does it  matter in any practical sense?  I would really 
like to know who cares,  and why?  Can anyone hear the difference? 
Three-thousanths of a  second?  Not my old brain.

73,
John, W2GW
K3  #384


- Original Message - 
From: Lyle Johnson  [EMAIL PROTECTED]
To: Elecraft Reflector  elecraft@mailman.qth.net
Sent: Saturday, March 29, 2008 5:21  PM
Subject: Re: [Elecraft] CW rise time mod


 Or do Rev A  RF boards have a lower value for C222 than that shown on the 
  schematic?

 Early production K3 RF boards have a 1 uF capacitor  instead of a 0.1 uF 
 capacitor installed at C222.  Yes, the  published schematics show a 0.1 uF 
 capacitor.  The effect of the  larger capacitor is to increase the TX 
 waveform rise time to about 8 ms  instead of 5 ms.

 Rev B RF boards have the correct 0.1 uF value  installed.  Sometime during 
 Rev A RF board production, the value  installed on the board was changed 
 from 1 uF to 0.1 uF.

  Surface mount ceramic capacitors are not marked with a value, so you 
  cannot tell which you have by visual inspection.

 You can  determine if you have a 1 uF rather than a 0.1 uF by:

 1)  Measuring the capacitance if you have a capacitance meter.

 2)  Looking at the Tx output RF envelope on an oscilloscope or station 
  monitor scope.  If the fall time and the rise time look very similar in  
 duration, you have the 0.1 uF cap. If the rise time is about 50% longer  
 than the fall time, you have the 1 uF capacitor.  You don't need  an 
 oscilloscope with an accurate time base to make this comparative  
 measurement.  If your oscilloscope has a low bandwidth (2 to 10  MHz), use 
 the 160 meter band.

 3) If you are concerned  that your unit may have the 1 uF capacitor and you 
 have no way to  determine it otherwise, you can just replace it with the 
 0.1 uF part  and sleep better at night :-)

 If you don't change it, you will  not damage anything.  Your K3 will just 
 have slightly softer  keying and an upcoming firmware adjustment of the 
 keying time will be  less accurate.

 73,

 Lyle KK7P

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**Create a Home Theater Like the Pros. Watch the video on AOL 
Home.  
(http://home.aol.com/diy/home-improvement-eric-stromer?video=15ncid=aolhom000301)
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[Elecraft] CW rise time mod

[David Pratt]

Elecraft says.
Some owners prefer a faster CW keying waveform rise time. The rise time 
can be reduced from about 8 milliseconds to 5 milliseconds without 
affecting the fall time by replacing capacitor C222 on the K3 main RF 
board with a 0.1 uF capacitor. This change will also allow a future 
firmware revision to further reduce rise time via a menu entry.


But the schematics of the RF Board Rev. A4 (Sheet 3 of 4), dated 
9/19/07, show C222 as being 0.1 already.  The instructions recommend 
removing the existing 0.1 and replacing it with another 0.1 !!  Surely 
to reduce the rise time the existing capacitor should be shunted with 
another one.


Or do Rev A RF boards have a lower value for C222 than that shown on the 
schematic?


73
--
David G4DMP
Leeds, England, UK


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[Elecraft] CW rise time mod

[Dave G4AON]

It's easy, read the revision marked on the board edge in marker pen 
(ouch, couldn't resist that one).


Confusion seems to surround this whole issue, my K3 serial 80, which was 
shipped as a kit in November definitely didn't have a 100nF capacitor at 
C222 as the rise time dropped from 8mS to 5mS when I replaced the 
surface mount capacitor with one from a pack of 100nF ones. Others have 
mentioned the change not having been done on K3s with serial numbers in 
the 300 range.


The safe bet is to check the waveform with an oscilloscope.

73 Dave G4AON
K3/100 #80
-

Elecraft says.
Some owners prefer a faster CW keying waveform rise time. The rise time
can be reduced from about 8 milliseconds to 5 milliseconds without
affecting the fall time by replacing capacitor C222 on the K3 main RF
board with a 0.1 uF capacitor. This change will also allow a future
firmware revision to further reduce rise time via a menu entry.

But the schematics of the RF Board Rev. A4 (Sheet 3 of 4), dated
9/19/07, show C222 as being 0.1 already. The instructions recommend
removing the existing 0.1 and replacing it with another 0.1 !! Surely
to reduce the rise time the existing capacitor should be shunted with
another one.

Or do Rev A RF boards have a lower value for C222 than that shown on the
schematic?

73
--
David G4DMP
Leeds, England, UK
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Re: [Elecraft] CW rise time mod

[Ken Wagner]

Hi David:

I measured C222 *in place* with my aade cap checker and it measured ~1 
uF(actually 0.965 uF)... not the 0.1 in the schematic. I'm guessing that 
the schematic available for download is not current with production. 
Someone else here mentioned that  C222 was 1 uF, but I don't remember 
who it was.


73,
Ken K3IU

David Pratt wrote:

Elecraft says.
Some owners prefer a faster CW keying waveform rise time. The rise 
time can be reduced from about 8 milliseconds to 5 milliseconds 
without affecting the fall time by replacing capacitor C222 on the K3 
main RF board with a 0.1 uF capacitor. This change will also allow a 
future firmware revision to further reduce rise time via a menu entry.


But the schematics of the RF Board Rev. A4 (Sheet 3 of 4), dated 
9/19/07, show C222 as being 0.1 already.  The instructions recommend 
removing the existing 0.1 and replacing it with another 0.1 !!  Surely 
to reduce the rise time the existing capacitor should be shunted with 
another one.


Or do Rev A RF boards have a lower value for C222 than that shown on 
the schematic?


73

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Re: [Elecraft] CW rise time mod

[David Pratt]

In a recent message, Ken Wagner [EMAIL PROTECTED] writes
I measured C222 *in place* with my aade cap checker and it measured ~1 
uF(actually 0.965 uF)... not the 0.1 in the schematic. I'm guessing 
that the schematic available for download is not current with 
production. Someone else here mentioned that  C222 was 1 uF, but I 
don't remember who it was.


Thanks Ken, and Dave G4AON, it looks as though a batch of RF boards were 
fitted with the wrong value of C222 SMD.  Perhaps we should all measure 
C222 before changing the capacitor.


73
--
David G4DMP
Leeds, England, UK


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Re: [Elecraft] CW rise time mod

[Don Ehrlich]

That was me .. My actual measurement was 0.985 microfarad when I checked the 
RF board in S/N 195 I rounded it up to 1 microfarad in my earlier 
report.


Don K7FJ


Someone else here mentioned that  C222 was 1 uF, but I don't remember who 
it was.


73,
Ken K3IU




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Re: [Elecraft] CW rise time mod

[Lyle Johnson]

Or do Rev A RF boards have a lower value for C222 than that shown on the 
schematic?


Early production K3 RF boards have a 1 uF capacitor instead of a 0.1 uF 
capacitor installed at C222.  Yes, the published schematics show a 0.1 
uF capacitor.  The effect of the larger capacitor is to increase the TX 
waveform rise time to about 8 ms instead of 5 ms.


Rev B RF boards have the correct 0.1 uF value installed.  Sometime 
during Rev A RF board production, the value installed on the board was 
changed from 1 uF to 0.1 uF.


Surface mount ceramic capacitors are not marked with a value, so you 
cannot tell which you have by visual inspection.


You can determine if you have a 1 uF rather than a 0.1 uF by:

1) Measuring the capacitance if you have a capacitance meter.

2) Looking at the Tx output RF envelope on an oscilloscope or station 
monitor scope.  If the fall time and the rise time look very similar in 
duration, you have the 0.1 uF cap. If the rise time is about 50% longer 
than the fall time, you have the 1 uF capacitor.  You don't need an 
oscilloscope with an accurate time base to make this comparative 
measurement.  If your oscilloscope has a low bandwidth (2 to 10 MHz), 
use the 160 meter band.


3) If you are concerned that your unit may have the 1 uF capacitor and 
you have no way to determine it otherwise, you can just replace it with 
the 0.1 uF part and sleep better at night :-)


If you don't change it, you will not damage anything.  Your K3 will just 
have slightly softer keying and an upcoming firmware adjustment of the 
keying time will be less accurate.


73,

Lyle KK7P

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Re: [Elecraft] CW rise time mod

[Ken Wagner K3IU]

I guess I didn't say... my K3 is #202
73,
Ken KIU

Don Ehrlich wrote:
That was me .. My actual measurement was 0.985 microfarad when I 
checked the RF board in S/N 195 I rounded it up to 1 microfarad in 
my earlier report.


Don K7FJ


Someone else here mentioned that  C222 was 1 uF, but I don't remember 
who it was.


73,
Ken K3IU






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RE: [Elecraft] CW rise time mod

[Ron D'Eau Claire]

Hi, David:

The original value for C222 was 0.01 uF. Wayne asked that it be changed to
0.1 uFd. 

I wasn't privy to the source of the comment that the rise time might be
further shortened in firmware. If Wayne plans to control the keying in
firmware, it's probably important that all the hardware be consistent with a
0.1uFd cap at C222 so the firmware works as planned. 

Ron AC7AC

-Original Message-

Elecraft says.
Some owners prefer a faster CW keying waveform rise time. The rise time 
can be reduced from about 8 milliseconds to 5 milliseconds without 
affecting the fall time by replacing capacitor C222 on the K3 main RF 
board with a 0.1 uF capacitor. This change will also allow a future 
firmware revision to further reduce rise time via a menu entry.

But the schematics of the RF Board Rev. A4 (Sheet 3 of 4), dated 
9/19/07, show C222 as being 0.1 already.  The instructions recommend 
removing the existing 0.1 and replacing it with another 0.1 !!  Surely 
to reduce the rise time the existing capacitor should be shunted with 
another one.

Or do Rev A RF boards have a lower value for C222 than that shown on the 
schematic?

73
-- 
David G4DMP
Leeds, England, UK


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RE: [Elecraft] CW rise time mod

[Ron D'Eau Claire]

Oops, make that originally a 1 uFD cap at C222. Now the recommended value is
0.1 uFd

Ron 

-Original Message-
From: Ron D'Eau Claire [mailto:[EMAIL PROTECTED] 
Sent: Saturday, March 29, 2008 2:26 PM
To: 'David Pratt'; 'Elecraft Reflector'
Subject: RE: [Elecraft] CW rise time mod


Hi, David:

The original value for C222 was 0.01 uF. Wayne asked that it be changed to
0.1 uFd. 

I wasn't privy to the source of the comment that the rise time might be
further shortened in firmware. If Wayne plans to control the keying in
firmware, it's probably important that all the hardware be consistent with a
0.1uFd cap at C222 so the firmware works as planned. 

Ron AC7AC

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Re: [Elecraft] CW rise time mod

[Joseph Trombino Jr]

Measured C222 in my K3 s/n 285 a while back and it is .1uf.

   73, Joe W2KJ
QRP, therefore I am
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Re: [Elecraft] CW rise time mod

[Vic K2VCO]

David Pratt wrote:

Elecraft says.
Some owners prefer a faster CW keying waveform rise time. The rise time 
can be reduced from about 8 milliseconds to 5 milliseconds without 
affecting the fall time by replacing capacitor C222 on the K3 main RF 
board with a 0.1 uF capacitor. This change will also allow a future 
firmware revision to further reduce rise time via a menu entry.


But the schematics of the RF Board Rev. A4 (Sheet 3 of 4), dated 
9/19/07, show C222 as being 0.1 already.  The instructions recommend 
removing the existing 0.1 and replacing it with another 0.1 !!  Surely 
to reduce the rise time the existing capacitor should be shunted with 
another one.


Or do Rev A RF boards have a lower value for C222 than that shown on the 
schematic?


As I understand it, Wayne called for the modification earlier, but for 
some reason it didn't get reflected in production. That's why the 
schematic doesn't agree.


The old value was 1 uf and it the new, correct value is 0.1 uf.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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Re: [Elecraft] CW rise time mod

[John Reiser]

People,

8 ms.- 5 ms.= 3 ms., does it matter in any practical sense?  I would really 
like to know who cares, and why?  Can anyone hear the difference? 
Three-thousanths of a second?  Not my old brain.


73,
John, W2GW
K3 #384


- Original Message - 
From: Lyle Johnson [EMAIL PROTECTED]

To: Elecraft Reflector elecraft@mailman.qth.net
Sent: Saturday, March 29, 2008 5:21 PM
Subject: Re: [Elecraft] CW rise time mod


Or do Rev A RF boards have a lower value for C222 than that shown on the 
schematic?


Early production K3 RF boards have a 1 uF capacitor instead of a 0.1 uF 
capacitor installed at C222.  Yes, the published schematics show a 0.1 uF 
capacitor.  The effect of the larger capacitor is to increase the TX 
waveform rise time to about 8 ms instead of 5 ms.


Rev B RF boards have the correct 0.1 uF value installed.  Sometime during 
Rev A RF board production, the value installed on the board was changed 
from 1 uF to 0.1 uF.


Surface mount ceramic capacitors are not marked with a value, so you 
cannot tell which you have by visual inspection.


You can determine if you have a 1 uF rather than a 0.1 uF by:

1) Measuring the capacitance if you have a capacitance meter.

2) Looking at the Tx output RF envelope on an oscilloscope or station 
monitor scope.  If the fall time and the rise time look very similar in 
duration, you have the 0.1 uF cap. If the rise time is about 50% longer 
than the fall time, you have the 1 uF capacitor.  You don't need an 
oscilloscope with an accurate time base to make this comparative 
measurement.  If your oscilloscope has a low bandwidth (2 to 10 MHz), use 
the 160 meter band.


3) If you are concerned that your unit may have the 1 uF capacitor and you 
have no way to determine it otherwise, you can just replace it with the 
0.1 uF part and sleep better at night :-)


If you don't change it, you will not damage anything.  Your K3 will just 
have slightly softer keying and an upcoming firmware adjustment of the 
keying time will be less accurate.


73,

Lyle KK7P

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RE: [Elecraft] CW rise time mod

[Ron D'Eau Claire]

I  certainly did not notice it on K3 S/N 10, nor did anyone I worked on CW.
But I seldom operate CW above 25 WPM. IIRC, it was a high speed operator who
noticed the 'soft' keying, probably working at rates well above 25 WPM.

Still, I made the change because, as the notes on the web page suggest,
there will be the ability to adjust the characteristic using the MENU
commands in the future. But that firmware will assume a particular hardware
configuration, and I wanted my hardware to match what the firmware expects. 

Ron AC7AC 

-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of John Reiser
Sent: Saturday, March 29, 2008 5:33 PM
To: Lyle Johnson; Elecraft Reflector
Subject: Re: [Elecraft] CW rise time mod


People,

8 ms.- 5 ms.= 3 ms., does it matter in any practical sense?  I would really 
like to know who cares, and why?  Can anyone hear the difference? 
Three-thousanths of a second?  Not my old brain.

73,
John, W2GW
K3 #384


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