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Elecraft K2 CW key shaping

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dl2ki

Elecraft K2 CW key shaping

Hi,

since someone told me that there is a small "chirp" in my K2-CW signal, I
would like to check the signal visually.

How can I display the CW Key envelope as shown in the document "Elecraft K2
Keying Modification Instructions", page 1.

An oscilloscope "Tektronix 2465A" is at my disposal, but I have little
experience with measuring instruments, since I only use them occasionally.

Thank you and 73
Wolfgang
DL2KI

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Vic Rosenthal

Re: Elecraft K2 CW key shaping

A chirp can't be seen visually on an oscilloscope (well, maybe on a
panadpter or spectrum analyzer if it is a very big one).

A chirp is a change in frequency of the transmitted signal. It is not
the same as a click, which is a wide signal caused by too-short rise and
fall times of the keyed envelope, or a badly shaped envelope. You can
see the envelope shape on an oscilloscope. But the change in frequency
caused by a chirp is very small in comparison with the frequency of the
signal.

The way to detect a chirp is to listen to the transmitted signal on a
second receiver. Your ear is very sensitive to changes in pitch.

73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
CWops no. 5
http://www.qsl.net/k2vco/
.
On 14/07/2020 9:29, dl2ki wrote:

> Hi,
>
> since someone told me that there is a small "chirp" in my K2-CW signal, I
> would like to check the signal visually.
>
> How can I display the CW Key envelope as shown in the document "Elecraft K2
> Keying Modification Instructions", page 1.
>
> An oscilloscope "Tektronix 2465A" is at my disposal, but I have little
> experience with measuring instruments, since I only use them occasionally.
>
> Thank you and 73
> Wolfgang
> DL2KI
>
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
> 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]
>

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vk2rq

Re: Elecraft K2 CW key shaping

Generally a chirp would be due to an unstable power supply, resistance in
the fuse holder, etc.. It can also be cause by poor decoupling/loading of
the oscillator circuit, but in the case of a well-designed circuit like the
K2, this would normally only arise with misplaced components or poor
connections.

On Tue, 14 Jul 2020 at 18:01, Victor Rosenthal 4X6GP <[hidden email]>
wrote:

> A chirp can't be seen visually on an oscilloscope (well, maybe on a
> panadpter or spectrum analyzer if it is a very big one).
>
> A chirp is a change in frequency of the transmitted signal. It is not
> the same as a click, which is a wide signal caused by too-short rise and
> fall times of the keyed envelope, or a badly shaped envelope. You can
> see the envelope shape on an oscilloscope. But the change in frequency
> caused by a chirp is very small in comparison with the frequency of the
> signal.
>
> The way to detect a chirp is to listen to the transmitted signal on a
> second receiver. Your ear is very sensitive to changes in pitch.
>
> 73,
> Victor, 4X6GP
> Rehovot, Israel
> Formerly K2VCO
> CWops no. 5
> http://www.qsl.net/k2vco/
> .
> On 14/07/2020 9:29, dl2ki wrote:
> > Hi,
> >
> > since someone told me that there is a small "chirp" in my K2-CW signal, I
> > would like to check the signal visually.
> >
> > How can I display the CW Key envelope as shown in the document "Elecraft
> K2
> > Keying Modification Instructions", page 1.
> >
> > An oscilloscope "Tektronix 2465A" is at my disposal, but I have little
> > experience with measuring instruments, since I only use them
> occasionally.
> >
> > Thank you and 73
> > Wolfgang
> > DL2KI
> >
> >
> >
> >
> > --
> > Sent from: http://elecraft.365791.n2.nabble.com/
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to [hidden email]
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

dl2ki

Re: Elecraft K2 CW key shaping

Hi,

thanks for the hints and information.

I will listen to the signal once with my K3. That seems to be the best way
to check the hint. But I will also have a look at the connector plugs and
power supply cables in my portable configuration.

73, Wolfgang
DL2KI

--
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