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Re: K2 intermittent problem

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Igor Sokolov-2

Re: K2 intermittent problem

Just discovered that knocking RF board in the region of the K14 and K15
relays makes the problem to appear or disappear. The offset does not depend
on the CW pitch setting and is close to 1 khz.

__________________________________________________________
My K2 developed a problem. In CW mode TX frequency is off the RX frequency
by about 1 kHz. The problem is intermittent. Sometimes it manifests itself,
sometimes it does not.
Can anybody give me a hint where to look? I was about to see if changing CW
pitch changes the offset but so far cannot make the problem to appear again.
So far there were no evidence that the problem is temperature dependant.

73, Igor UA9CDC

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Don Wilhelm-4

Re: K2 intermittent problem

Igor,

An intermittent problem of that nature is usually associated with a bad
solder connection.
Reflow the soldering (adding a little bit of flux from new solder) with
a hot (400 degC) iron.

73,
Don W3FPR

On 4/8/2012 4:28 AM, Igor Sokolov wrote:

> Just discovered that knocking RF board in the region of the K14 and K15
> relays makes the problem to appear or disappear. The offset does not depend
> on the CW pitch setting and is close to 1 khz.
>
> __________________________________________________________
> My K2 developed a problem. In CW mode TX frequency is off the RX frequency
> by about 1 kHz. The problem is intermittent. Sometimes it manifests itself,
> sometimes it does not.
> Can anybody give me a hint where to look? I was about to see if changing CW
> pitch changes the offset but so far cannot make the problem to appear again.
> So far there were no evidence that the problem is temperature dependant.
>
> 73, Igor UA9CDC
>
> ______________________________________________________________
> 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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Geoffrey Mackenzie-Kennedy-3

Re: K2 intermittent problem

In reply to this post by Igor Sokolov-2

Igor,

When the problem appears, is the offset always the same plus minus say 5 Hz?

Also, did you try knocking the RF board in the region of the PLL reference
oscillator's crystal X1?

73,
Geoff
LX2AO

On April 08, 2012 at 10:28 +0200, Igor Sokolov wrote:

> Just discovered that knocking RF board in the region of the K14 and K15
> relays makes the problem to appear or disappear. The offset does not
> depend
> on the CW pitch setting and is close to 1 khz.

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Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Igor Sokolov-2

Re: K2 intermittent problem

In reply to this post by Don Wilhelm-4

The problem was finally tracked down to X3,X4 crystals. Changing one of them
(only one was found in a local shop) cured the intermittent frequency
change. BFO frequency range is within the accepted limits (a bit more then
3.6 kHz). VFO linearization and CAL FIL is done. Now I have another
problem. TX and RX frequencies do not coincide. The difference is band
dependant. It is 30Hz on 80m and 260Hz on 28 MHz. Although the radio is
usable with engaged RIT (OR XIT) I would like to cure the new problem.
Can somebody root me in the right direction please

73, Igor UA9CDC

----- Original Message -----
From: "Don Wilhelm" <[hidden email]>
To: "Igor Sokolov" <[hidden email]>
Cc: "Elecraft Reflector" <[hidden email]>
Sent: Sunday, April 08, 2012 7:26 PM
Subject: Re: [Elecraft] K2 intermittent problem

> Igor,
>
> An intermittent problem of that nature is usually associated with a bad
> solder connection.
> Reflow the soldering (adding a little bit of flux from new solder) with a
> hot (400 degC) iron.
>
> 73,
> Don W3FPR
>
> On 4/8/2012 4:28 AM, Igor Sokolov wrote:
>> Just discovered that knocking RF board in the region of the K14 and K15
>> relays makes the problem to appear or disappear. The offset does not
>> depend
>> on the CW pitch setting and is close to 1 khz.
>>
>> __________________________________________________________
>> My K2 developed a problem. In CW mode TX frequency is off the RX
>> frequency
>> by about 1 kHz. The problem is intermittent. Sometimes it manifests
>> itself,
>> sometimes it does not.
>> Can anybody give me a hint where to look? I was about to see if changing
>> CW
>> pitch changes the offset but so far cannot make the problem to appear
>> again.
>> So far there were no evidence that the problem is temperature dependant.
>>
>> 73, Igor UA9CDC
>>
>> ______________________________________________________________
>> 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
>>

Don Wilhelm-4

Re: K2 intermittent problem

Igor,

What mode? How are you determining that the TX and RX frequencies are
different?
There should be no difference in SSB, and in CW the difference should be
equal to the sidetone pitch.

73,
Don W3FPR

On 4/23/2012 1:23 PM, Igor Sokolov wrote:

> The problem was finally tracked down to X3,X4 crystals. Changing one of them
> (only one was found in a local shop) cured the intermittent frequency
> change. BFO frequency range is within the accepted limits (a bit more then
> 3.6 kHz). VFO linearization and CAL FIL is done. Now I have another
> problem. TX and RX frequencies do not coincide. The difference is band
> dependant. It is 30Hz on 80m and 260Hz on 28 MHz. Although the radio is
> usable with engaged RIT (OR XIT) I would like to cure the new problem.
> Can somebody root me in the right direction please
>
> 73, Igor UA9CDC
>

Igor Sokolov-2

Re: K2 intermittent problem

> Igor,
>
> What mode? How are you determining that the TX and RX frequencies are
> different?
> There should be no difference in SSB, and in CW the difference should be
> equal to the sidetone pitch.
>
> 73,
> Don W3FPR
>
>
> On 4/23/2012 1:23 PM, Igor Sokolov wrote:
>> The problem was finally tracked down to X3,X4 crystals. Changing one of
>> them
>> (only one was found in a local shop) cured the intermittent frequency
>> change. BFO frequency range is within the accepted limits (a bit more
>> then
>> 3.6 kHz). VFO linearization and CAL FIL is done. Now I have another
>> problem. TX and RX frequencies do not coincide. The difference is band
>> dependant. It is 30Hz on 80m and 260Hz on 28 MHz. Although the radio is
>> usable with engaged RIT (OR XIT) I would like to cure the new problem.
>> Can somebody root me in the right direction please
>>
>> 73, Igor UA9CDC
>>

Don Wilhelm-4

Re: K2 intermittent problem

Igor,

After giving your question some thought - I would suggest making another
attempt with the K2 set to receive on the FL1 filter (the same filter as
used for transmit).

If you still have the shift between TX and RX, the problem is most
likely in the way the the sidetone shift offset is being handled (Wayne
would have to answer that situation, I do not have a clue to what goes
on inside the firmware)

However, if the shift is absent with that setup, you can solve the
problem with the BFO settings for the filter.

I really don't think that limited shift will make a great difference in
actual use, but I must admit it could be annoying.

73,
Don W3FPR

On 4/23/2012 3:44 PM, Igor Sokolov wrote:

> Did it with well aligned and checked K3 in CW mode plus external frequency
> counter.
> Transmit on K2, receive on K3 tuned to the same pitch as set in the menu.
> Then TX on the K3 RX on K2. TX frequency in both cases checked by the
> external counter.
>
> 73, Igor UA9CDC
>
>> Igor,
>>
>> What mode? How are you determining that the TX and RX frequencies are
>> different?
>> There should be no difference in SSB, and in CW the difference should be
>> equal to the sidetone pitch.
>>
>> 73,
>> Don W3FPR
>>
>>
>> On 4/23/2012 1:23 PM, Igor Sokolov wrote:
>>> The problem was finally tracked down to X3,X4 crystals. Changing one of
>>> them
>>> (only one was found in a local shop) cured the intermittent frequency
>>> change. BFO frequency range is within the accepted limits (a bit more
>>> then
>>> 3.6 kHz). VFO linearization and CAL FIL is done. Now I have another
>>> problem. TX and RX frequencies do not coincide. The difference is band
>>> dependant. It is 30Hz on 80m and 260Hz on 28 MHz. Although the radio is
>>> usable with engaged RIT (OR XIT) I would like to cure the new problem.
>>> Can somebody root me in the right direction please
>>>
>>> 73, Igor UA9CDC
>>>
> ______________________________________________________________
> 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
>

Igor Sokolov-2

Re: K2 intermittent problem

In reply to this post by Don Wilhelm-4

Did it with well aligned and checked K3 in CW mode plus external frequency
counter.
Transmit on K2, receive on K3 tuned to the same pitch as set in the menu.
Then TX on the K3 RX on K2. TX frequency in both cases checked by the
external counter. TX frequency is always higher then RX. The worst case is
on 28 MHZ where it is 260 Hz.
Do you have any ideas Don?

73, Igor UA9CDC

----- Original Message -----
From: "Don Wilhelm" <[hidden email]>
To: "Igor Sokolov" <[hidden email]>
Cc: "Elecraft Reflector" <[hidden email]>
Sent: Monday, April 23, 2012 11:48 PM
Subject: Re: [Elecraft] K2 intermittent problem

Don Wilhelm-4

Re: K2 intermittent problem

Igor,

Did you receive the email I sent yesterday? The content is copied below:
---------------------------------
I would suggest making another attempt with the K2 set to receive on the
FL1 filter (the same filter as used for transmit).

If you still have the shift between TX and RX, the problem is most
likely in the way the the sidetone shift offset is being handled (Wayne
would have to answer that situation, I do not have a clue to what goes
on inside the firmware)

However, if the shift is absent with that setup, you can solve the
problem with the BFO settings for the filter.
---------------------------------

73,
Don W3FPR

On 4/24/2012 11:58 AM, Igor Sokolov wrote:

> Did it with well aligned and checked K3 in CW mode plus external frequency
> counter.
> Transmit on K2, receive on K3 tuned to the same pitch as set in the menu.
> Then TX on the K3 RX on K2. TX frequency in both cases checked by the
> external counter. TX frequency is always higher then RX. The worst case is
> on 28 MHZ where it is 260 Hz.
> Do you have any ideas Don?
>
> 73, Igor UA9CDC
>
> ----- Original Message -----
> From: "Don Wilhelm"<[hidden email]>
> To: "Igor Sokolov"<[hidden email]>
> Cc: "Elecraft Reflector"<[hidden email]>
> Sent: Monday, April 23, 2012 11:48 PM
> Subject: Re: [Elecraft] K2 intermittent problem
>
>
>> Igor,
>>
>> What mode? How are you determining that the TX and RX frequencies are
>> different?
>> There should be no difference in SSB, and in CW the difference should be
>> equal to the sidetone pitch.
>>
>> 73,
>> Don W3FPR
>>
>>
>> On 4/23/2012 1:23 PM, Igor Sokolov wrote:
>>> The problem was finally tracked down to X3,X4 crystals. Changing one of
>>> them
>>> (only one was found in a local shop) cured the intermittent frequency
>>> change. BFO frequency range is within the accepted limits (a bit more
>>> then
>>> 3.6 kHz). VFO linearization and CAL FIL is done. Now I have another
>>> problem. TX and RX frequencies do not coincide. The difference is band
>>> dependant. It is 30Hz on 80m and 260Hz on 28 MHz. Although the radio is
>>> usable with engaged RIT (OR XIT) I would like to cure the new problem.
>>> Can somebody root me in the right direction please
>>>
>>> 73, Igor UA9CDC
>>>
> ______________________________________________________________
> 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
>