K3SYN3 with and without shielding

[Sverre Holm (LA3ZA)]

I am about to install the second receiver in the K3. I now have two synthesizers, the old no 1 which has been made up to date with a paralleled resistor (KSYN3 DDS Gain Modification) and which does not have any shield. Then I have a new one with a shield which is several mm thick and covers most of the PCB.

I would guess the shield is there for a purpose, so is it advisable that I swap the synthesizers and use the shielded one as no 1, which is also used for transmission I presume?


Sverre

[Brett Howard]

Couldn't hurt as its going to have all the latest mods.

That is a stiffener and not really a "shield". Go to the mod kits and parts
section on the elecraft website and you can read the installation
instructions on that stiffener and even buy one to upgrade your other synth
if you wish...

~Brett (N7MG)

On Jun 23, 2010 7:04 AM, "Sverre Holm (LA3ZA)" <[hidden email]> wrote:
>
> I am about to install the second receiver in the K3. I now have two
> synthesizers, the old no 1 which has been made up to date with a
paralleled
> resistor (
> http://www.elecraft.com/K3/mods/KSYN3%20DDS%20Gain%20Modification.pdfKSYN3
> DDS Gain Modification ) and which does not have any shield. Then I have a
> new one with a shield which is several mm thick and covers most of the
PCB.

>
> I would guess the shield is there for a purpose, so is it advisable that I
> swap the synthesizers and use the shielded one as no 1, which is also used
> for transmission I presume?
>
>
> Sverre
>
> -----
> Sverre, LA3ZA
>
> K2 #2198, K3 #3391
> http://www.qslnet.de/member/la3za/K2/mod.html LA3ZA Unofficial Guide to K2
> modifications
> --
> View this message in context:

http://elecraft.365791.n2.nabble.com/K3SYN3-with-and-without-shielding-tp5213399p5213399.html
> Sent from the [K3] mailing list archive at Nabble.com.
> ______________________________________________________________
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[The Smiths]

That is NOT a "shield" that is a "stiffenner" plate.  It does NOTHING for RF Shielding.  That plate was intended to keep your Synth board from bowing when you have the internal speaker on with the CW or Audio monitor up LOUD while transmitting.  It was found that in SOME cases loud audio monitoring with internal speakers would cause the CW to chirp or SSB to move Freq. while transmitting.

If you want that plate it is available as a "mod" and costs $20.00.  You can find it on Elecrafts site.  Keeping in mind that you only use 1 Synth board for transmitting you should only really need one plate (if any at all).

The reason that you MAY want to consider having it is because , just like the resistor mod that fixed another possible Chirpping with the CW, you MAY some day swap your Synth boards for Testing or some other reason, and if and when you do, you will want to assure yourself that the Mods are on the Transmit board yet again.

I hope this answers your questions..

 

PS.  Look closely at the Plate, you will notice that it actually does NOT cover any parts on the board.  That side of the board has all the parts sticking through that plate.  Most of the parts on that PCB are mounted SMD on the other side.

 


 

> Date: Wed, 23 Jun 2010 07:04:33 -0700
> From: [hidden email]
> To: [hidden email]
> Subject: [Elecraft] K3SYN3 with and without shielding
>
>
> I am about to install the second receiver in the K3. I now have two
> synthesizers, the old no 1 which has been made up to date with a paralleled
> resistor (
> http://www.elecraft.com/K3/mods/KSYN3%20DDS%20Gain%20Modification.pdf KSYN3
> DDS Gain Modification ) and which does not have any shield. Then I have a
> new one with a shield which is several mm thick and covers most of the PCB.
>
> I would guess the shield is there for a purpose, so is it advisable that I
> swap the synthesizers and use the shielded one as no 1, which is also used
> for transmission I presume?
>
>
> Sverre
>
> -----
> Sverre, LA3ZA
>
> K2 #2198, K3 #3391
> http://www.qslnet.de/member/la3za/K2/mod.html LA3ZA Unofficial Guide to K2
> modifications
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/K3SYN3-with-and-without-shielding-tp5213399p5213399.html
> Sent from the [K3] 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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[Sverre Holm (LA3ZA)]

Thanks for comments - OK it's a stiffener, not a shield.

Looks like I should put the stiffened KSYN3 in the primary position then, eliminating the possibility for transmitting a chirpy signal when monitoring the transmission on the internal loudspeaker. With time I can perhaps upgrade the second synthesizer with a stiffener.

[Bill W4ZV]

Sverre Holm (LA3ZA) wrote

Thanks for comments - OK it's a stiffener, not a shield.

Looks like I should put the stiffened KSYN3 in the primary position then, eliminating the possibility for transmitting a chirpy signal when monitoring the transmission on the internal loudspeaker. With time I can perhaps upgrade the second synthesizer with a stiffener.

Both the DDS Gain Mod (for chirp) and the Stiffener Mod primarily affect the transmitted signal, so both mods should be installed in the Main VCO.  For KRX3 users, Elecraft recommends making mods to both VCO boards in case those boards should accidentally be swapped in the future.  If you take care to mark the modified board, IMO it should not be necessary to modify the other one.

73,  Bill

[Alexandr Kobranov]

I am not sure - aren´t there 2 modifications of KSYN3 module - one for
avoiding PLL problems in higher temperature (by changing R from 89k to 50k)
and the second one for curinng "chirp" problem by increasing of the gain of
some transistor by replacement of some other resistor? I suppose only the
first one is a part of KSYN3 stiffener u/g.
Or am I wrong?
(Just to make clear which one is curing temperature stability, which one
"chirp" problem and stiffener for avoiding "microphonic" effects.)
73!
L.exa, ok1dst
K3/100 #727

P.S.: Hope to see some of you in Friedrichshafen this week!



2010/6/23 Bill W4ZV <[hidden email]>

>
>
> Sverre Holm (LA3ZA) wrote:
> >
> > Thanks for comments - OK it's a stiffener, not a shield.
> >
> > Looks like I should put the stiffened KSYN3 in the primary position then,
> > eliminating the possibility for transmitting a chirpy signal when
> > monitoring the transmission on the internal loudspeaker. With time I can
> > perhaps upgrade the second synthesizer with a stiffener.
> >
>
> Both the DDS Gain Mod (for chirp) and the Stiffener Mod primarily affect
> the
> transmitted signal, so both mods should be installed in the Main VCO.  For
> KRX3 users, Elecraft recommends making mods to both VCO boards in case
> those
> boards should accidentally be swapped in the future.  If you take care to
> mark the modified board, IMO it should not be necessary to modify the other
> one.
>
> 73,  Bill
> --
> View this message in context:
> http://elecraft.365791.n2.nabble.com/K3SYN3-with-and-without-shielding-tp5213399p5214089.html
> Sent from the [K3] mailing list archive at Nabble.com.
> ______________________________________________________________
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>

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[P.B. Christensen]

The first KSYN3 stability change affects R10 with its value moving from 82K
to 56K.  In the second change, R20 is changed to 25-ohms.  In both cases, a
new resistor can be bridged across the older resistor to establish the new
component value.

Paul, W9AC

----- Original Message -----
From: "Alexandr Kobranov" <[hidden email]>
To: "Bill W4ZV" <[hidden email]>
Cc: <[hidden email]>
Sent: Wednesday, June 23, 2010 1:49 PM
Subject: Re: [Elecraft] K3SYN3 with and without stiffener (was: shielding)


I am not sure - aren´t there 2 modifications of KSYN3 module - one for
avoiding PLL problems in higher temperature (by changing R from 89k to 50k)
and the second one for curinng "chirp" problem by increasing of the gain of
some transistor by replacement of some other resistor? I suppose only the
first one is a part of KSYN3 stiffener u/g.

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[Bill W4ZV]

Alexandr Kobranov wrote

I am not sure - aren´t there 2 modifications of KSYN3 module - one for
avoiding PLL problems in higher temperature (by changing R from 89k to 50k)
and the second one for curinng "chirp" problem by increasing of the gain of
some transistor by replacement of some other resistor? I suppose only the
first one is a part of KSYN3 stiffener u/g.
Or am I wrong?
(Just to make clear which one is curing temperature stability, which one
"chirp" problem and stiffener for avoiding "microphonic" effects.)

Yes, I forgot about the oldest one regarding the stability at high temperatures.  There are actually 3 different mods for 3 different issues...see below for details:

http://www.mail-archive.com/[e-mail]/msg96813.html

73,  Bill

[Alexandr Kobranov]

Yes - that´s it, exactly. And part of KSYN3 stiffener u/g (
http://www.elecraft.com/manual/ELECRAFT%20KSYN3%20Stiffener%20Mod%20Rev%20D.pdf)
is only the first - R10 replacement (56k SMD resistor is listed in the set
of parts for this u/g).
So - for K3 S/N less or around 3922 - maybe the second one (
http://www.elecraft.com/K3/mods/KSYN3%20DDS%20Gain%20Modification.pdf) is
better to be done in the same time I think (you need separate 51Ohm resistor
ready for it to place accros R20).
As I want to order stiffener u/g for my #727 I will be prepared to perform
both together.

73!
L. -dst-
K3/100 #727


2010/6/23 Paul Christensen <[hidden email]>

> The first KSYN3 stability change affects R10 with its value moving from 82K
> to 56K.  In the second change, R20 is changed to 25-ohms.  In both cases, a
> new resistor can be bridged across the older resistor to establish the new
> component value.
>
> Paul, W9AC
>
> ----- Original Message -----
> From: "Alexandr Kobranov" <[hidden email]>
> To: "Bill W4ZV" <[hidden email]>
> Cc: <[hidden email]>
> Sent: Wednesday, June 23, 2010 1:49 PM
> Subject: Re: [Elecraft] K3SYN3 with and without stiffener (was: shielding)
>
>
> I am not sure - aren´t there 2 modifications of KSYN3 module - one for
> avoiding PLL problems in higher temperature (by changing R from 89k to 50k)
> and the second one for curinng "chirp" problem by increasing of the gain of
> some transistor by replacement of some other resistor? I suppose only the
> first one is a part of KSYN3 stiffener u/g.
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> 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
>

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