K3 spurs

[Roger D Johnson]

I was watching 6m yesterday and noticed several spurs. They were spaced 39kHz
apart. Amplitude dropped but didn't disappear when switched to dummy load.

I have the K3 with new synthesizer boards. Just wondering if anyone else seeing
something similar. IOW is it something in the K3 or external?

73, Roger

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[Clay Autery-2]

I don't know where your antenna is located, how your feedline runs, or
where your dummy load is located, but....

You have some kind of switch mode power supply or similar device that is
coupling with your antenna and/or feedline.

That the signal dissipates some when on the dummy load is a clue to
where the source might be...

I'd be almost positive it is external to the K3...

Are you powering the K3 with a SM power supply?


73,

Clay, KY5G


On 05/15/18 09:22, Roger D Johnson wrote:

> I was watching 6m yesterday and noticed several spurs. They were
> spaced 39kHz
> apart. Amplitude dropped but didn't disappear when switched to dummy
> load.
>
> I have the K3 with new synthesizer boards. Just wondering if anyone
> else seeing
> something similar. IOW is it something in the K3 or external?
>
> 73, Roger
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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[K9MA]

I've seen a K3 generate spurs when the power supply was overloaded, and
went into current limit.

73,

Scott  K9MA


On 5/15/2018 15:38, Clay Autery wrote:

> I don't know where your antenna is located, how your feedline runs, or
> where your dummy load is located, but....
>
> You have some kind of switch mode power supply or similar device that
> is coupling with your antenna and/or feedline.
>
> That the signal dissipates some when on the dummy load is a clue to
> where the source might be...
>
> I'd be almost positive it is external to the K3...
>
> Are you powering the K3 with a SM power supply?
>
>
> 73,
>
> Clay, KY5G
>
>
> On 05/15/18 09:22, Roger D Johnson wrote:
>> I was watching 6m yesterday and noticed several spurs. They were
>> spaced 39kHz
>> apart. Amplitude dropped but didn't disappear when switched to dummy
>> load.
>>
>> I have the K3 with new synthesizer boards. Just wondering if anyone
>> else seeing
>> something similar. IOW is it something in the K3 or external?
>>
>> 73, Roger
>>
>> ______________________________________________________________
>> 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]

--
Scott  K9MA

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[Elecraft mailing list]

 If you have an older K3 there was a problem with them generating a spur.  I had the problem when a friend reported hearing me on a 2nd freq.I'm guessing nobody still has an older K3 though with this problem.
We have determined that a small number of K3/100s and KPA3s left the factory earlier this year (2009) with capacitor C3 installed by mistake on early Revision C KPA3 PC boards.  This part location should be empty on Rev. C KPA3s.  Installation of C3 causes the PA bias supply to oscillate on some KPA3s at approximately 15-20 kHz, resulting in spurious TX sidebands at that spacing from the carrier.
Info is on the Mods & Notes page almost at the bottom. 
http://www.elecraft.com/K3/k3_app_notes.htm
BillK3WJV


    On Tuesday, May 15, 2018, 9:30:41 AM EDT, Roger D Johnson <[hidden email]> wrote:  
 
 I was watching 6m yesterday and noticed several spurs. They were spaced 39kHz
apart. Amplitude dropped but didn't disappear when switched to dummy load.

I have the K3 with new synthesizer boards. Just wondering if anyone else seeing
something similar. IOW is it something in the K3 or external?

73, Roger

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