[KX3] JT9 Drift Problem

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[KX3] JT9 Drift Problem

Jim Campbell
I have a K2 that I have been using for almost a year on JT65. No
problems whatsoever. I obtained WAS and eWAS in about 4 months of casual
operating.

A few months ago I got a KX3 and for the last few days have been trying
it out on JT9. I haven't been able to make a single contact. I would
call CQ and see someone answer me on the same frequency but WSJT-X
wouldn't produce a decode. I could answer a CQ and see a reply but again
no decode. (I was running 5 watts.)

This afternoon I noticed something unusual. After a 1-minute
transmission all of the received signals during the next minute had a
skew (drift) and none decoded. The drift was for a total of about minus
ten Hertz during the minute after the transmission. If I didn't transmit
during the next one-minute cycle there was little drift and the received
signals would decode.

I began to speculate that during the one minute transmission some
temperature-sensitive component(s) heated up and caused a change in
frequency. During the next minute they cooled and the frequency returned
to normal. I played with this for a little while and the results were
consistent. In the minute following a transmission there were no decodes
but during all subsequent minutes signals would decode.

I switched back to the K2 and had five normal JT9 contacts, the nicest
of which was John, ZD7JC on St. Helena Island in the South Atlantic. All
this with a low dipole and 10 W. (He gave me a signal report of +00
which meant that I could have been using one watt or less.)

I assembled the KX3 and believe that I ran all the tests and
adjustments. Any suggestions as to what I can do to tame this
temperature sensitivity?

73,

Jim - W4BQP
K2 #2268, KX3 #2875

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Re: [KX3] JT9 Drift Problem

Matt Zilmer
Hi Jim,

You might want to run the temperature compensation procedure on your
KX3.  If it's performed correctly, you should see < 2 Hz drift over
the temperature range.  You may want to purchase the XG50, used as a
stable frequency referece, or you can supply your own.

The procedure is shown in this document:
http://www.elecraft.com/manual/KX3%20Custom%20VFO%20TC%20rev%20A9.pdf

73,
matt W6NIA

On Wed, 27 Mar 2013 18:43:01 -0400, you wrote:

>I have a K2 that I have been using for almost a year on JT65. No
>problems whatsoever. I obtained WAS and eWAS in about 4 months of casual
>operating.
>
>A few months ago I got a KX3 and for the last few days have been trying
>it out on JT9. I haven't been able to make a single contact. I would
>call CQ and see someone answer me on the same frequency but WSJT-X
>wouldn't produce a decode. I could answer a CQ and see a reply but again
>no decode. (I was running 5 watts.)
>
>This afternoon I noticed something unusual. After a 1-minute
>transmission all of the received signals during the next minute had a
>skew (drift) and none decoded. The drift was for a total of about minus
>ten Hertz during the minute after the transmission. If I didn't transmit
>during the next one-minute cycle there was little drift and the received
>signals would decode.
>
>I began to speculate that during the one minute transmission some
>temperature-sensitive component(s) heated up and caused a change in
>frequency. During the next minute they cooled and the frequency returned
>to normal. I played with this for a little while and the results were
>consistent. In the minute following a transmission there were no decodes
>but during all subsequent minutes signals would decode.
>
>I switched back to the K2 and had five normal JT9 contacts, the nicest
>of which was John, ZD7JC on St. Helena Island in the South Atlantic. All
>this with a low dipole and 10 W. (He gave me a signal report of +00
>which meant that I could have been using one watt or less.)
>
>I assembled the KX3 and believe that I ran all the tests and
>adjustments. Any suggestions as to what I can do to tame this
>temperature sensitivity?
>
>73,
>
>Jim - W4BQP
>K2 #2268, KX3 #2875
>
>______________________________________________________________
>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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Re: [KX3] JT9 Drift Problem

Jim Campbell
Thanks, Matt,

I purchased an XG50 at the time I purchased the KX3. I remember running
a procedure with the KX3/XG50 but it was nowhere near as involved as the
one shown in the referenced manual.

I will run the new procedure and let the list know how it went.

73,

Jim - W4BQP

On 3/27/2013 6:50 PM, Matt Zilmer wrote:

> Hi Jim,
>
> You might want to run the temperature compensation procedure on your
> KX3.  If it's performed correctly, you should see < 2 Hz drift over
> the temperature range.  You may want to purchase the XG50, used as a
> stable frequency referece, or you can supply your own.
>
> The procedure is shown in this document:
> http://www.elecraft.com/manual/KX3%20Custom%20VFO%20TC%20rev%20A9.pdf
>
> 73,
> matt W6NIA
>
>

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Re: [KX3] JT9 Drift Problem

Matt Zilmer
Good luck, Jim.  Though ... I hope luck isn't the main factor!

73,
matt W6NIA

On Wed, 27 Mar 2013 19:14:33 -0400, you wrote:

>Thanks, Matt,
>
>I purchased an XG50 at the time I purchased the KX3. I remember running
>a procedure with the KX3/XG50 but it was nowhere near as involved as the
>one shown in the referenced manual.
>
>I will run the new procedure and let the list know how it went.
>
>73,
>
>Jim - W4BQP
>
>On 3/27/2013 6:50 PM, Matt Zilmer wrote:
>> Hi Jim,
>>
>> You might want to run the temperature compensation procedure on your
>> KX3.  If it's performed correctly, you should see < 2 Hz drift over
>> the temperature range.  You may want to purchase the XG50, used as a
>> stable frequency referece, or you can supply your own.
>>
>> The procedure is shown in this document:
>> http://www.elecraft.com/manual/KX3%20Custom%20VFO%20TC%20rev%20A9.pdf
>>
>> 73,
>> matt W6NIA
>>
>>
>
>______________________________________________________________
>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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Re: [KX3] JT9 Drift Problem

Jim Campbell
Matt,

I went through the procedure this morning and now have no drift :-)

Thanks for the help.

73,

Jim - W4BQP
On 3/27/2013 7:59 PM, Matt Zilmer wrote:

> Good luck, Jim.  Though ... I hope luck isn't the main factor!
>
> 73,
> matt W6NIA
>
> On Wed, 27 Mar 2013 19:14:33 -0400, you wrote:
>
>> Thanks, Matt,
>>
>> I purchased an XG50 at the time I purchased the KX3. I remember running
>> a procedure with the KX3/XG50 but it was nowhere near as involved as the
>> one shown in the referenced manual.
>>
>> I will run the new procedure and let the list know how it went.
>>
>> 73,
>>
>> Jim - W4BQP
>>
>>

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Re: [KX3] JT9 Drift Problem

Matt Zilmer
Excellent news, and exactly the reason for the procedure (JT modes,
WSPR, etc.).

It takes time to execute the procedure, but the results are definitely
worth it.  I first found the problem running WSPR, when every station
decoded drifted the same span +/- 1 Hz.  There was about 8-10 Hz drift
from the end of a TX slot to the beginning of the second next one
(about 2 min 10 sec for WSPR.  That was way too much drift.

73,
matt

On Thu, 28 Mar 2013 14:28:50 -0400, you wrote:

>Matt,
>
>I went through the procedure this morning and now have no drift :-)
>
>Thanks for the help.
>
>73,
>
>Jim - W4BQP
>On 3/27/2013 7:59 PM, Matt Zilmer wrote:
>> Good luck, Jim.  Though ... I hope luck isn't the main factor!
>>
>> 73,
>> matt W6NIA
>>
>> On Wed, 27 Mar 2013 19:14:33 -0400, you wrote:
>>
>>> Thanks, Matt,
>>>
>>> I purchased an XG50 at the time I purchased the KX3. I remember running
>>> a procedure with the KX3/XG50 but it was nowhere near as involved as the
>>> one shown in the referenced manual.
>>>
>>> I will run the new procedure and let the list know how it went.
>>>
>>> 73,
>>>
>>> Jim - W4BQP
>>>
>>>
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