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K2: Modulation on CW signal

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Calvin Jones

K2: Modulation on CW signal

Hello, First time posting to the list.

Completed K2 #7239 today. Made a contact with a station on cw, 10 watts, 7.1065 mhz. He reported back that my CW signal had a very heavy ripple on the signal.

I connected the output to a Oscilloscope and was able to see a ripple on the waveform when keying a solid carrier at a few watts. Also listened to my signal on another receiver and could hear a very bad modulated CW tone.

This is a barebones K2 with no options installed at this point. Every measurement in the testing was all within specs and the alignment of the radio had no problems. Power output on all bands was OK.

Thanks for any help in correcting this problem.
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Geoffrey Mackenzie-Kennedy-3

Re: K2: Modulation on CW signal

Hello Calvin,

Welcome to the Elecraft List.

Were you using a dummy load or your antenna when looking at your K2's output
with an Oscilloscope?

Is the frequency of the modulation/ ripple which you see equal to the
sidetone frequency, or a harmonic of the sidetone's frequency, which you are
using when transmitting CW?

Also, if you transmit CW on another frequency in the 40m band, say 7.030
MHz, using the same power 10 watts, is the ripple still the same, any
"weaker", or not there at all?

And lastly, do you see the ripple on all bands, or on some bands but not
others, or only on 40m?

Sorry for asking these many questions, but there are several possible resons
why the ripple is there.

73,

Geoff
LX2AO

On October 22, 2012 at 5:04 AM, Calvin Jones wrote:

> Hello, First time posting to the list.
>
> Completed K2 #7239 today. Made a contact with a station on cw, 10 watts,
> 7.1065 mhz. He reported back that my CW signal had a very heavy ripple on
> the signal.
>
> I connected the output to a Oscilloscope and was able to see a ripple on
> the waveform when keying a solid carrier at a few watts. Also listened to
> my signal on another receiver and could hear a very bad modulated CW tone.
>
> This is a barebones K2 with no options installed at this point. Every
> measurement in the testing was all within specs and the alignment of the
> radio had no problems. Power output on all bands was OK.
>
> Thanks for any help in correcting this problem.

Don Wilhelm-4

Re: K2: Modulation on CW signal

In reply to this post by Calvin Jones

Calvin,

Do you have anything with a transformer within 2 feet of the K2? If so,
isolate the K2 by moving it away from everything and see if the ripple
goes away.

If the problem disappears with the isolation, you can install the
optional VCOSHLDKT which shields the VFO inductor.

73,
Don W3FPR

On 10/21/2012 11:04 PM, Calvin Jones wrote:

> Hello, First time posting to the list.
>
> Completed K2 #7239 today. Made a contact with a station on cw, 10 watts, 7.1065 mhz. He reported back that my CW signal had a very heavy ripple on the signal.
>
> I connected the output to a Oscilloscope and was able to see a ripple on the waveform when keying a solid carrier at a few watts. Also listened to my signal on another receiver and could hear a very bad modulated CW tone.
>
> This is a barebones K2 with no options installed at this point. Every measurement in the testing was all within specs and the alignment of the radio had no problems. Power output on all bands was OK.
>
> Thanks for any help in correcting this problem.
> ______________________________________________________________
> 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
>

Calvin Jones

Re: K2: Modulation on CW signal

The radio was sitting by 50 amp astron power supply which was on.

Moved radio up to bedroom this morning w/ dummy load, powered by an optima blue top deep cycle battery. Same results. Could tune in to CW signal using yaesu radio in basement.

Ordered the optional VCOSHLDKT today anyway since the K2 will end up down by the power supply.

On Oct 22, 2012, at 7:23 AM, Don Wilhelm <[hidden email]> wrote:

> Calvin,
>
> Do you have anything with a transformer within 2 feet of the K2? If so, isolate the K2 by moving it away from everything and see if the ripple goes away.
>
> If the problem disappears with the isolation, you can install the optional VCOSHLDKT which shields the VFO inductor.
>
> 73,
> Don W3FPR
>
> On 10/21/2012 11:04 PM, Calvin Jones wrote:
>> Hello, First time posting to the list.
>>
>> Completed K2 #7239 today. Made a contact with a station on cw, 10 watts, 7.1065 mhz. He reported back that my CW signal had a very heavy ripple on the signal.
>>
>> I connected the output to a Oscilloscope and was able to see a ripple on the waveform when keying a solid carrier at a few watts. Also listened to my signal on another receiver and could hear a very bad modulated CW tone.
>>
>> This is a barebones K2 with no options installed at this point. Every measurement in the testing was all within specs and the alignment of the radio had no problems. Power output on all bands was OK.
>>
>> Thanks for any help in correcting this problem.
>> ______________________________________________________________
>> 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
>>

Christophe F8ACF-56

Re: K2: Modulation on CW signal

hello list,

what it is VCOSHLDKT, is there a direct link on the site Elecraft?

thank you again for the information, it must learn.

K2 # 7369

73 , Christophe F8ACF-56

________________________________
De : Cal <[hidden email]>
À : "[hidden email]" <[hidden email]>
Cc : "[hidden email]" <[hidden email]>
Envoyé le : Lundi 22 octobre 2012 19h19
Objet : Re: [Elecraft] K2: Modulation on CW signal

The radio was sitting by 50 amp astron power supply which was on.

Moved radio up to bedroom this morning w/ dummy load, powered by an optima blue top deep cycle battery. Same results. Could tune in to CW signal using yaesu radio in basement.

Ordered the optional VCOSHLDKT today anyway since the K2 will end up down by the power supply.

On Oct 22, 2012, at 7:23 AM, Don Wilhelm <[hidden email]> wrote:

______________________________________________________________
Elecraft mailing list
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Please help support this email list: http://www.qsl.net/donate.html
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html

Mike K8CN

Re: K2: Modulation on CW signal

Hi Christophe,

The VCO shield kit may be found here:

http://www.elecraft.com/order_form_parts.htm#K2%20Parts

Look at the first line labeled K2VCOSHLDKT.

73,
Mike, K8CN