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Poor CW note more testing and a question (rather long-ish...)

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Chuck Chandler

Poor CW note more testing and a question (rather long-ish...)

After several reports that my CW tone sounded less than perfect I've been
on a hunt for possible causes. Looking at the TX waveform on my P3 it does
look more sausage-shaped than I see in the P3 manual.

So far I've determined my power supply was a little low and sagging a
little under full power. After changing cabling and adjusting the PS, I
now have 14.2V displayed on the K3 at rest, 13.9 to 14.0V at the 25W level
used to drive the KPA500, and 13.7 to 13.8V at 100W output. All that now
seems as it should be, but the waveform on the P3 is still elongated.

My KPA500 on a 240V outlet shows HV of 73.5V at rest, 57.3V with 500W
output. This is a little on the low side, and I may move the HV tap to
bring it back up above 60V under load.

On air testing today with a neighbor I got the report that my CW sounds
just fine until the amp is in line. Then it is described as "some kind of
artifact... like a bell sound... like a delay." This is consistent with
the other report I had been getting of a "ringing, bell-like" note to my
CW. This is most apparent at 30 wpm, as I would be running in a contest.

So far, all the reports I have received from fellow amateurs have been
after a CW Ops weekly contest, during which I usually am running at 30 wpm
and 500W output. During rag chews with a bug at 22-25 wpm and 500W nobody
has said anything bad about the CW note.

The rig, KAT500 tuner and amp are interconnected via two E850463 Aux
Interface Cables as shown on page 5 of the KAT500 Manual, Rev. C6
(3/8/2017). CW for contesting is generated by N1MM+ via the K3S USB
interface. I have a K1EL Winkeyer on order in case the root cause is the
computer... but that elongated waveform remains the most likely factor to
resolve.

My guess is the root cause of all this, power supply issues resolved for
now, is the elongated waveform I see on the P3. My rise time seems to be
at least 3 or 4 times longer than what I see in the ARRL product reviews or
even in the P3 manual showing an example of a CW waveform.

I have submitted a contact form at the Elecraft support web page, but its
the weekend and with them all working from home I wouldn't mind the
collective wisdom of the group as to any other avenues of investigation.

And, many thanks for the help so far!

73 de Chuck, WS1L
--

===================
Chuck Chandler
[hidden email]
===================
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ANDY DURBIN

Poor CW note more testing and a question (rather long-ish...)

"I got the report that my CW sounds just fine until the amp is in line. Then it is described as "some kind of artifact... like a bell sound... like a delay." This is consistent with the other report I had been getting of a "ringing, bell-like" note to my CW. This is most apparent at 30 wpm, as I would be running in a contest."

I'm probably well out of my depth here but could this be caused by incorrectly configured ALC feedback from the KPA500 to the rig? That should be easy to test by simply disconnecting the AUX cables and running the CW test again.

73,
Andy, k3wyc
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Buck

Re: Poor CW note more testing and a question (rather long-ish...)

In reply to this post by Chuck Chandler

My HV shows 74 volts resting and 60 key down

k4ia, Buck
K3s# 11497
Honor Roll 8B DXCC
EasyWayHamBooks.com

On 4/26/2020 4:26 PM, Chuck Chandler wrote:

> After several reports that my CW tone sounded less than perfect I've been
> on a hunt for possible causes. Looking at the TX waveform on my P3 it does
> look more sausage-shaped than I see in the P3 manual.
>
> So far I've determined my power supply was a little low and sagging a
> little under full power. After changing cabling and adjusting the PS, I
> now have 14.2V displayed on the K3 at rest, 13.9 to 14.0V at the 25W level
> used to drive the KPA500, and 13.7 to 13.8V at 100W output. All that now
> seems as it should be, but the waveform on the P3 is still elongated.
>
> My KPA500 on a 240V outlet shows HV of 73.5V at rest, 57.3V with 500W
> output. This is a little on the low side, and I may move the HV tap to
> bring it back up above 60V under load.
>
> On air testing today with a neighbor I got the report that my CW sounds
> just fine until the amp is in line. Then it is described as "some kind of
> artifact... like a bell sound... like a delay." This is consistent with
> the other report I had been getting of a "ringing, bell-like" note to my
> CW. This is most apparent at 30 wpm, as I would be running in a contest.
>
> So far, all the reports I have received from fellow amateurs have been
> after a CW Ops weekly contest, during which I usually am running at 30 wpm
> and 500W output. During rag chews with a bug at 22-25 wpm and 500W nobody
> has said anything bad about the CW note.
>
> The rig, KAT500 tuner and amp are interconnected via two E850463 Aux
> Interface Cables as shown on page 5 of the KAT500 Manual, Rev. C6
> (3/8/2017). CW for contesting is generated by N1MM+ via the K3S USB
> interface. I have a K1EL Winkeyer on order in case the root cause is the
> computer... but that elongated waveform remains the most likely factor to
> resolve.
>
> My guess is the root cause of all this, power supply issues resolved for
> now, is the elongated waveform I see on the P3. My rise time seems to be
> at least 3 or 4 times longer than what I see in the ARRL product reviews or
> even in the P3 manual showing an example of a CW waveform.
>
> I have submitted a contact form at the Elecraft support web page, but its
> the weekend and with them all working from home I wouldn't mind the
> collective wisdom of the group as to any other avenues of investigation.
>
> And, many thanks for the help so far!
>
> 73 de Chuck, WS1L
>

Bob McGraw - K4TAX

Re: Poor CW note more testing and a question (rather long-ish...)

In reply to this post by ANDY DURBIN

I do use ALC between my KPA500 and my K3S.   I do find that the ALC
setup and calibration is critical for correct operation. As to the
effects of it being set incorrectly, I can't say.   I do know it must be
done for every band and the amp ALC will be displayed on my K3S.   The
amp ALC THR value on my amp runs from 145 to 120 depending on band.
One value does not work for all bands.

73

Bob, K4TAX

On 4/26/2020 3:37 PM, Andy Durbin wrote:

> "I got the report that my CW sounds just fine until the amp is in line. Then it is described as "some kind of artifact... like a bell sound... like a delay." This is consistent with the other report I had been getting of a "ringing, bell-like" note to my CW. This is most apparent at 30 wpm, as I would be running in a contest."
>
> I'm probably well out of my depth here but could this be caused by incorrectly configured ALC feedback from the KPA500 to the rig? That should be easy to test by simply disconnecting the AUX cables and running the CW test again.
>
> 73,
> Andy, k3wyc
> ______________________________________________________________
> Elecraft mailing list
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>

Jim Brown-10

Re: Poor CW note more testing and a question (rather long-ish...)

In reply to this post by ANDY DURBIN

On 4/26/2020 1:37 PM, Andy Durbin wrote:

> I'm probably well out of my depth here but could this be caused by
> incorrectly configured ALC feedback from the KPA500 to the rig?

In general, ALC between an amp and a rig is a recipe for clicks and
splatter. Most authorities advise against using it. This is not new --
it's in the manual for Ten Tec legal limit amps from the late '70s and
for every amp I've owned since.

If it is used, it should be set for well above normal output power so
that it only kicks in to reduce drive when something breaks in the
antenna system or the operator experiences brain cramp and transmits
into the wrong antenna. :) And good solid state amps are well enough
protected that they do that without ALC.

73, Jim K9YCX

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ANDY DURBIN

Re: Poor CW note more testing and a question (rather long-ish...)

In reply to this post by ANDY DURBIN

"In general, ALC between an amp and a rig is a recipe for clicks and splatter. Most authorities advise against using it. This is not new -- it's in the manual for Ten Tec legal limit amps from the late '70s and for every amp I've owned since."

The OP has a KPA500 and K3S interconnect by an Elecraft AUX cable. This means that ALC is connected (Aux cable pin 15) and opens the possibility that it is not configured correctly. What I don't know is whether incorrectly configured ALC could cause the reported problem. I suspect that would depend on the time constant(s) of the ALC loop.

73,
Andy, k3wyc

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Dick Dievendorff-4

Re: Poor CW note more testing and a question (rather long-ish...)

External ALC is enabled on the K3 and K3S with a menu entry that defaults to
OFF. See page 29 of the K3S owner's manual.

73 de Dick, K6KR

-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of Andy Durbin
Sent: Sunday, April 26, 2020 17:20
To: [hidden email]
Subject: Re: [Elecraft] Poor CW note more testing and a question (rather
long-ish...)

"In general, ALC between an amp and a rig is a recipe for clicks and
splatter. Most authorities advise against using it. This is not new -- it's
in the manual for Ten Tec legal limit amps from the late '70s and for every
amp I've owned since."

The OP has a KPA500 and K3S interconnect by an Elecraft AUX cable. This
means that ALC is connected (Aux cable pin 15) and opens the possibility
that it is not configured correctly. What I don't know is whether
incorrectly configured ALC could cause the reported problem. I suspect that
would depend on the time constant(s) of the ALC loop.

73,
Andy, k3wyc

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Chuck Chandler

Re: Poor CW note more testing and a question (rather long-ish...)

My EXT ALC menu is set to the default of OFF t-40. The soft waveform is
displayed on the P3 apparently the same shape whether the amp is in use or
standby.

73,

Chuck, WS1L

On Sun, Apr 26, 2020 at 19:36 Dick Dievendorff <[hidden email]> wrote:

> External ALC is enabled on the K3 and K3S with a menu entry that defaults
> to
> OFF. See page 29 of the K3S owner's manual.
>
> 73 de Dick, K6KR
>
> -----Original Message-----
> From: [hidden email] <[hidden email]>
> On
> Behalf Of Andy Durbin
> Sent: Sunday, April 26, 2020 17:20
> To: [hidden email]
> Subject: Re: [Elecraft] Poor CW note more testing and a question (rather
> long-ish...)
>
> "In general, ALC between an amp and a rig is a recipe for clicks and
> splatter. Most authorities advise against using it. This is not new -- it's
> in the manual for Ten Tec legal limit amps from the late '70s and for every
> amp I've owned since."
>
> The OP has a KPA500 and K3S interconnect by an Elecraft AUX cable. This
> means that ALC is connected (Aux cable pin 15) and opens the possibility
> that it is not configured correctly. What I don't know is whether
> incorrectly configured ALC could cause the reported problem. I suspect
> that
> would depend on the time constant(s) of the ALC loop.
>
> 73,
> Andy, k3wyc
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message
> delivered to [hidden email]
>
> ______________________________________________________________
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>
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--
Sent from Gmail Mobile Chuck Chandler [hidden email]
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NK7Z

Re: Poor CW note more testing and a question (rather long-ish...)

In reply to this post by Jim Brown-10

I run my KPA500 with no ALC, and have from day 1. Somewhere I have seen
a recommendation, (I think by Elecraft), to not run ALC with the KPA500.

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources

On 4/26/20 3:43 PM, Jim Brown wrote:

> On 4/26/2020 1:37 PM, Andy Durbin wrote:
>
> > I'm probably well out of my depth here but could this be caused by
> > incorrectly configured ALC feedback from the KPA500 to the rig?
>
> In general, ALC between an amp and a rig is a recipe for clicks and
> splatter. Most authorities advise against using it. This is not new --
> it's in the manual for Ten Tec legal limit amps from the late '70s and
> for every amp I've owned since.
>
> If it is used, it should be set for well above normal output power so
> that it only kicks in to reduce drive when something breaks in the
> antenna system or the operator experiences brain cramp and transmits
> into the wrong antenna. :) And good solid state amps are well enough
> protected that they do that without ALC.
>
> 73, Jim K9YCX
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

donovanf

Re: Poor CW note more testing and a question (rather long-ish...)

Page 27 of the K3 Manual addresses proper use of ALC with the K3:

External ALC External ALC should only be used to protect your amplifier

during operation into a failed load, or during a prolonged overdrive condition.
ALC should not be used as a way to clip or compress fast voice peaks,
or as a primary means of amplifier or K3 power output control. DO NOT
set the K3’s power level to maximum and adjust amp output using the
amp’s ALC control. This will result in splatter and key clicks. Instead,
adjust the drive on each band so it’s just below ALC activation level.

https://ftp.elecraft.com/K3/Manuals%20Downloads/E740107%20K3%20Owner's%20man%20D10.pdf

73
Frank
W3LPL

----- Original Message -----

From: "Dave Cole" <[hidden email]>
To: [hidden email]
Sent: Monday, April 27, 2020 2:12:16 AM
Subject: Re: [Elecraft] Poor CW note more testing and a question (rather long-ish...)

I run my KPA500 with no ALC, and have from day 1. Somewhere I have seen
a recommendation, (I think by Elecraft), to not run ALC with the KPA500.

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources

On 4/26/20 3:43 PM, Jim Brown wrote:

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