K3STFNR

[Richard Thorpe-2]

I am awaiting the K3EXREF mod to become available.  While I have my K3 apart should I upgrade and add the K3STFNR plates to the two synthesizer boards in my K3.  I've checked the archives with mixed results as to the efficacy of this mod.  Any opinions out there?  Thank you.

R Thorpe K6CG
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[Julian, G4ILO]

That's a good question. I haven't noticed the problem the stiffener solves, but I don't use the internal speaker. But one day I might.

Richard Thorpe-2 wrote

I am awaiting the K3EXREF mod to become available.  While I have my K3 apart should I upgrade and add the K3STFNR plates to the two synthesizer boards in my K3.  I've checked the archives with mixed results as to the efficacy of this mod.  Any opinions out there?  Thank you.

[Bill W4ZV]

Richard Thorpe-2 wrote

I am awaiting the K3EXREF mod to become available.  While I have my K3 apart should I upgrade and add the K3STFNR plates to the two synthesizer boards in my K3.  I've checked the archives with mixed results as to the efficacy of this mod.  Any opinions out there?  Thank you.

The problem this solves is audio modulation of the VCO by the internal speaker which can cause spurs at the modulation frequency around the fundamental.  If you don't use the internal speaker and don't run external speakers at the threshold of pain, the mod is probably unnecessary.  I nearly always use headphones so it's not an issue.  

73,  Bill  W4ZV

[Raymond Anderson]

Hi Bill

   You would only need to mod the main board as the second is never used on
transmit so does not have a problem.
    I would go ahead and add it so if you should ever want to use the
internal speaker you could without problems.

Ray K8RDJ

On Wed, Apr 27, 2011 at 6:37 PM, Bill W4ZV <[hidden email]> wrote:

>
> Richard Thorpe-2 wrote:
> >
> > I am awaiting the K3EXREF mod to become available.  While I have my K3
> > apart should I upgrade and add the K3STFNR plates to the two synthesizer
> > boards in my K3.  I've checked the archives with mixed results as to the
> > efficacy of this mod.  Any opinions out there?  Thank you.
> >
>
> The problem this solves is audio modulation of the VCO by the internal
> speaker which can cause spurs at the modulation frequency around the
> fundamental.  If you don't use the internal speaker and don't run external
> speakers at the threshold of pain, the mod is probably unnecessary.  I
> nearly always use headphones so it's not an issue.
>
> 73,  Bill  W4ZV
>
>
> --
> View this message in context:
> http://elecraft.365791.n2.nabble.com/K3STFNR-tp6311266p6311419.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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[Bill W4ZV]

On Wed, Apr 27, 2011 at 7:33 PM, Raymond Anderson <[hidden email]>wrote:

>
>    You would only need to mod the main board as the second is never used on
> transmit so does not have a problem.


True but Elecraft recommends doing both boards if you have the KRX3:

"If your K3 is equipped with the KRX3 subreceiver it will have two KSYN3
synthesizers. Both boards should be modified if the user chooses to make
this modification."

http://www.elecraft.com/manual/ELECRAFT%20KSYN3%20Stiffener%20Mod%20Rev%20D.pdf

I believe this is to prevent accidentally swapping the KSYN3 boards if you
ever needed to remove them (although it's fairly easy to tell them apart
because of the shield).  I actually did this mod to both K3SYNs, not because
of acoustic modulation issues, but because I felt the stiffener might
provide additional RF shielding.

73,  Bill  W4ZV
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[Guy, K2AV]

I found that it cleaned up some birdies, as the heavy aluminum
stiffener plate does shield the board.  It takes the same time to do
two boards as to do one.  You can get RX microphonics as well, and
that can happen with both boards if you have the KRX3.

I did both of mine and I'm happy I did.

73, Guy.

On Wed, Apr 27, 2011 at 7:33 PM, Raymond Anderson <[hidden email]> wrote:

> Hi Bill
>
>   You would only need to mod the main board as the second is never used on
> transmit so does not have a problem.
>    I would go ahead and add it so if you should ever want to use the
> internal speaker you could without problems.
>
> Ray K8RDJ
>
> On Wed, Apr 27, 2011 at 6:37 PM, Bill W4ZV <[hidden email]> wrote:
>
>>
>> Richard Thorpe-2 wrote:
>> >
>> > I am awaiting the K3EXREF mod to become available.  While I have my K3
>> > apart should I upgrade and add the K3STFNR plates to the two synthesizer
>> > boards in my K3.  I've checked the archives with mixed results as to the
>> > efficacy of this mod.  Any opinions out there?  Thank you.
>> >
>>
>> The problem this solves is audio modulation of the VCO by the internal
>> speaker which can cause spurs at the modulation frequency around the
>> fundamental.  If you don't use the internal speaker and don't run external
>> speakers at the threshold of pain, the mod is probably unnecessary.  I
>> nearly always use headphones so it's not an issue.
>>
>> 73,  Bill  W4ZV
>>
>>
>> --
>> View this message in context:
>> http://elecraft.365791.n2.nabble.com/K3STFNR-tp6311266p6311419.html
>> Sent from the Elecraft mailing list archive at 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
>>
> ______________________________________________________________
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