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[KX3] JT9 Drift Problem

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Jim Campbell

[KX3] JT9 Drift Problem

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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Matt Zilmer

Re: [KX3] JT9 Drift Problem

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

______________________________________________________________
Elecraft mailing list
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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

Jim Campbell

Re: [KX3] JT9 Drift Problem

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
>
>

Matt Zilmer

Re: [KX3] JT9 Drift Problem

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

Jim Campbell

Re: [KX3] JT9 Drift Problem

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
>>
>>

Matt Zilmer

Re: [KX3] JT9 Drift Problem

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
>>>
>>>