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K3 slightly off frequency

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K3 slightly off frequency

A few of us in Fremont, CA have a weekly 10 meter net. I have a friend with a K3 who always sounds off frequency. When I use my K3, I've been told that I am off frequency. There are a couple of KX3 users who don't seem to have a problem. When I use my Kenwood TS-590 I seem to be on frequency.
Is the K3 known, in general, for being slightly off frequency?
Thanks, Steve KG6HJU
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Bill Frantz

Re: K3 slightly off frequency

There is a procedure in the manual under "Calibration
Procedures". "Reference Oscillator". Using WWV can get you close
enough for most uses.

73 Bill AE6JV

On 4/9/17 at 10:05 PM, [hidden email] (Steve Wilson
via Elecraft) wrote:

>A few of us in Fremont, CA have a weekly 10 meter net. I have a
>friend with a K3 who always sounds off frequency. When I use my
>K3, I've been told that I am off frequency. There are a couple
>of KX3 users who don't seem to have a problem. When I use my
>Kenwood TS-590 I seem to be on frequency.
>Is the K3 known, in general, for being slightly off frequency?

-----------------------------------------------------------------------
Bill Frantz | Privacy is dead, get over | Periwinkle
(408)356-8506 | it. | 16345
Englewood Ave
www.pwpconsult.com | - Scott McNealy | Los Gatos,
CA 95032

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Roger

Re: K3 slightly off frequency

CONTENTS DELETED

The author has deleted this message.

Don Wilhelm

Re: K3 slightly off frequency

In reply to this post by Elecraft mailing list

Steve,

The K3 is not 'known' for being off frequency.
Turn to page 50 and do the Reference Oscillator calibration. If you do
not have a frequency counter that is accurate enough +/-1Hz or better at
49 MHz, you should use Method 2.

73,
Don W3FPR

On 4/9/2017 1:05 AM, Steve Wilson via Elecraft wrote:
> A few of us in Fremont, CA have a weekly 10 meter net. I have a friend with a K3 who always sounds off frequency. When I use my K3, I've been told that I am off frequency. There are a couple of KX3 users who don't seem to have a problem. When I use my Kenwood TS-590 I seem to be on frequency.
> Is the K3 known, in general, for being slightly off frequency?
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Mike Harris-9

Re: K3 slightly off frequency

In reply to this post by Roger

Immediate apologies, this is a tad long but hopefully interesting.

My K3 has the new synths (2), K144XV with REF Lock option and all is
well without doing the KREF3 modification. I guess this is an it either
works or it don't situation.

With respect to the post about off frequency, not a simple answer.

Firstly accuracy and resolution or precision are not to be confused, one
doesn't imply the other. The K3 display may read to 1Hz but that doesn't
mean it is accurate to 1Hz. If folks in a net all set their various
digital displays to the same frequency it doesn't mean they are all on
the same frequency.

As has been mentioned there is a perfectly good method of adjusting
calibration detailed in the handbook using WWV. It doesn't directly tune
or otherwise adjust the reference oscillator (TCXO) but lets whatever is
involved with controlling the synths what the reference frequency really
is so that the error can compensated for mathematically. That is my
understanding. I have been using this WWV method for the past nine years
and was convinced that the TXCO was probably drifting with age and have
often said that the CONFIG: REF CAL is not a one off adjustment. This
unfortunately turns out not to be the whole story.

Now it has to be said, the TXCO does drift, shock, horror. The high
stability option is described as being +/-1ppm but actually seems to
achieve 0.5ppm, at least mine does. How do I know this? I don't have a
frequency counter, or at least I didn't and in fact you don't need one
as will be discovered later. What I do have is the K3 external reference
frequency lock option fitted and recently purchased a Leo Bodnar GPS
disciplined reference clock which provides the necessary 10MHz drive for
the ext ref option. With a new toy you have go to play and what I
discovered follows.

With the GPS source up and running, turning on the K3 and enabling the
external ref feature the REF CAL measured TXCO frequency will be
displayed, counted by the ref lock module. This frequency will be seen
to change with warm up. My TXCO has a positive drift of approx 26Hz+/- a
couple in the first three minutes, for the next 30 minutes it drifts a
further 6Hz. Thereafter it slowly drifts until after four hours it tops
out at +57Hz or so and by this measurement method stops drifting.

However, there is more. At the same time as noting the REF CAL frequency
every minute, for the first hour, I also recorded the front panel (FP)
temperature. This started at 23C and over the measurement period
increased to 38C. It was observed that the rise in FP temp and the drift
follow a similar trajectory. As would be expected.

I have monitored the REF CAL frequency for a couple of months now and
note that the TXCO drift on my unit always maxes out at more or less the
same reading.

I have reached the conclusion that if at least two hours of warm up are
allowed and a WWV cal operation is then performed you will be in a
pretty good place with respect to total drift and subsequent overall
frequency (dial) accuracy.

It is easy to discover the pattern and extent of the drift of the TXCO
in your K3 without any external measuring equipment, external ref locks
or such.

1. From cold tune to a WWV frequency you will be able to receive
reliably for a few hours. Higher the better.
2. Wait 5 minutes or you will be chasing a moving target.
3. Perform a REF CAL and note the reading.
4. Perform a REF CAL every half hour, less if you feel like it and note
the readings.
5. Eventually the reading will really slow down and more or less stop
changing.
6. Choose a reading that indicates that the bulk of the drift has
happened, (1-2 hours)
7. Set REF CAL to that reading and sleep well. Good enough for HF.

Given the highest and lowest frequency readings a further experiment can
be performed to discover the consequences of the TXCO drift on dial
accuracy. It only takes a few minutes.

1. Set REF CALL to the lowest recorded frequency and tune the K3 to a
stable test frequency, I used my XG3, note the "dial" reading in fine
frequency display, 3 digits after the decimal point. I used the CW auto
spot feature to do the final tune.
2. Set REF CAL to the highest recorded frequency and retune the K3 as
above noting the "dial" frequency.

The lowest to highest REF CAL frequency is the total TXCO drift in Hz.
The lowest to highest "dial" frequency will indicate the consequence of
that TXCO drift in Hz. You will be pleased to note that the two do not
match. The K3 tuned frequency change is rather less than the TXCO drift.

Reset the REF CAL reading to that you previously chose to be your K3's
sweat spot.

The above shows why I was wrong in relating the REF CAL frequency
changes to TXCO ageing. In reality it all comes down to warm up time.

I hope this was worth the read.

Regards,

Mike VP8NO

On 09/04/2017 05:51, Roger via Elecraft wrote:
> KREF3MDKT This modification increases the output levels from the KREF3
> Reference Oscillator to provide proper drive levels for K3 transceivers
> equipped with a KSYN3A synthesizers the KRX3 or KRX3A sub receiver and the
> K144XV 2-meter transceiver.
>
> 73, Roger
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Elecraft mailing list

Re: K3 slightly off frequency

In reply to this post by Elecraft mailing list

If I understand correctly, your near Fremont CA. I had a two week turn around in Watsonville for Calibration. The charge was about $100. I drove it there. Saved the postage charges. Don't forget to call to obtain authorization for the return. It's also a good time to get hardware updates. Ted wp4cw.

On Apr 9, 2017 9:16 AM, Mike Harris <[hidden email]> wrote:

>
> Immediate apologies, this is a tad long but hopefully interesting.
>
> My K3 has the new synths (2), K144XV with REF Lock option and all is
> well without doing the KREF3 modification. I guess this is an it either
> works or it don't situation.
>
> With respect to the post about off frequency, not a simple answer.
>
> Firstly accuracy and resolution or precision are not to be confused, one
> doesn't imply the other. The K3 display may read to 1Hz but that doesn't
> mean it is accurate to 1Hz. If folks in a net all set their various
> digital displays to the same frequency it doesn't mean they are all on
> the same frequency.
>
> As has been mentioned there is a perfectly good method of adjusting
> calibration detailed in the handbook using WWV. It doesn't directly tune
> or otherwise adjust the reference oscillator (TCXO) but lets whatever is
> involved with controlling the synths what the reference frequency really
> is so that the error can compensated for mathematically. That is my
> understanding. I have been using this WWV method for the past nine years
> and was convinced that the TXCO was probably drifting with age and have
> often said that the CONFIG: REF CAL is not a one off adjustment. This
> unfortunately turns out not to be the whole story.
>
> Now it has to be said, the TXCO does drift, shock, horror. The high
> stability option is described as being +/-1ppm but actually seems to
> achieve 0.5ppm, at least mine does. How do I know this? I don't have a
> frequency counter, or at least I didn't and in fact you don't need one
> as will be discovered later. What I do have is the K3 external reference
> frequency lock option fitted and recently purchased a Leo Bodnar GPS
> disciplined reference clock which provides the necessary 10MHz drive for
> the ext ref option. With a new toy you have go to play and what I
> discovered follows.
>
> With the GPS source up and running, turning on the K3 and enabling the
> external ref feature the REF CAL measured TXCO frequency will be
> displayed, counted by the ref lock module. This frequency will be seen
> to change with warm up. My TXCO has a positive drift of approx 26Hz+/- a
> couple in the first three minutes, for the next 30 minutes it drifts a
> further 6Hz. Thereafter it slowly drifts until after four hours it tops
> out at +57Hz or so and by this measurement method stops drifting.
>
> However, there is more. At the same time as noting the REF CAL frequency
> every minute, for the first hour, I also recorded the front panel (FP)
> temperature. This started at 23C and over the measurement period
> increased to 38C. It was observed that the rise in FP temp and the drift
> follow a similar trajectory. As would be expected.
>
> I have monitored the REF CAL frequency for a couple of months now and
> note that the TXCO drift on my unit always maxes out at more or less the
> same reading.
>
> I have reached the conclusion that if at least two hours of warm up are
> allowed and a WWV cal operation is then performed you will be in a
> pretty good place with respect to total drift and subsequent overall
> frequency (dial) accuracy.
>
> It is easy to discover the pattern and extent of the drift of the TXCO
> in your K3 without any external measuring equipment, external ref locks
> or such.
>
> 1. From cold tune to a WWV frequency you will be able to receive
> reliably for a few hours. Higher the better.
> 2. Wait 5 minutes or you will be chasing a moving target.
> 3. Perform a REF CAL and note the reading.
> 4. Perform a REF CAL every half hour, less if you feel like it and note
> the readings.
> 5. Eventually the reading will really slow down and more or less stop
> changing.
> 6. Choose a reading that indicates that the bulk of the drift has
> happened, (1-2 hours)
> 7. Set REF CAL to that reading and sleep well. Good enough for HF.
>
> Given the highest and lowest frequency readings a further experiment can
> be performed to discover the consequences of the TXCO drift on dial
> accuracy. It only takes a few minutes.
>
> 1. Set REF CALL to the lowest recorded frequency and tune the K3 to a
> stable test frequency, I used my XG3, note the "dial" reading in fine
> frequency display, 3 digits after the decimal point. I used the CW auto
> spot feature to do the final tune.
> 2. Set REF CAL to the highest recorded frequency and retune the K3 as
> above noting the "dial" frequency.
>
> The lowest to highest REF CAL frequency is the total TXCO drift in Hz.
> The lowest to highest "dial" frequency will indicate the consequence of
> that TXCO drift in Hz. You will be pleased to note that the two do not
> match. The K3 tuned frequency change is rather less than the TXCO drift.
>
> Reset the REF CAL reading to that you previously chose to be your K3's
> sweat spot.
>
> The above shows why I was wrong in relating the REF CAL frequency
> changes to TXCO ageing. In reality it all comes down to warm up time.
>
> I hope this was worth the read.
>
> Regards,
>
> Mike VP8NO
>
>
>
> On 09/04/2017 05:51, Roger via Elecraft wrote:
> > KREF3MDKT This modification increases the output levels from the KREF3
> > Reference Oscillato

Bill K9YEQ

Re: K3 slightly off frequency

Yes! Tnx.

Have a great day!
Bill
K9YEQ

________________________________
From: Elecraft <[hidden email]> on behalf of teodoro martinez via Elecraft <[hidden email]>
Sent: Sunday, April 9, 2017 11:41:08 AM
To: Mike; elecraft
Subject: Re: [Elecraft] K3 slightly off frequency

If I understand correctly, your near Fremont CA. I had a two week turn around in Watsonville for Calibration. The charge was about $100. I drove it there. Saved the postage charges. Don't forget to call to obtain authorization for the return. It's also a good time to get hardware updates. Ted wp4cw.

On Apr 9, 2017 9:16 AM, Mike Harris <[hidden email]> wrote:

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briancom

Re: K3 slightly off frequency

In reply to this post by Mike Harris-9

All true. Note that the standard oscillator takes two hours to stop
drifting instead of four. Also the TCXO isn't. There is no temperature
feedback implemented. One is essentially seeing the stability of the
native oscillator. Too bad feedback isn't implemented, I'd bet a lot of
drift noted would disappear.

Not discussed is the "last digit" syndrome. Only believe the last digit
displayed if you can check that it is accurate.

With the standard synthesizers, as one tunes up the band the true
frequency deviates from the displayed by up to +/-4 Hz. There are times
when one tunes up and the RX actually goes to a lower frequency. Same
problem when tuning downwards. In other words, there is electronic
"backlash". One has no way of knowing which point of this sawtooth
error curve you are when choosing to calibrate to WWV. This is
essentially fixed with the new synthesizers.

73 de Brian/K3KO

On 4/9/2017 16:16 PM, Mike Harris wrote:

> Immediate apologies, this is a tad long but hopefully interesting.
>
> My K3 has the new synths (2), K144XV with REF Lock option and all is
> well without doing the KREF3 modification. I guess this is an it either
> works or it don't situation.
>
> With respect to the post about off frequency, not a simple answer.
>
> Firstly accuracy and resolution or precision are not to be confused, one
> doesn't imply the other. The K3 display may read to 1Hz but that doesn't
> mean it is accurate to 1Hz. If folks in a net all set their various
> digital displays to the same frequency it doesn't mean they are all on
> the same frequency.
>
> As has been mentioned there is a perfectly good method of adjusting
> calibration detailed in the handbook using WWV. It doesn't directly tune
> or otherwise adjust the reference oscillator (TCXO) but lets whatever is
> involved with controlling the synths what the reference frequency really
> is so that the error can compensated for mathematically. That is my
> understanding. I have been using this WWV method for the past nine years
> and was convinced that the TXCO was probably drifting with age and have
> often said that the CONFIG: REF CAL is not a one off adjustment. This
> unfortunately turns out not to be the whole story.
>
> Now it has to be said, the TXCO does drift, shock, horror. The high
> stability option is described as being +/-1ppm but actually seems to
> achieve 0.5ppm, at least mine does. How do I know this? I don't have a
> frequency counter, or at least I didn't and in fact you don't need one
> as will be discovered later. What I do have is the K3 external reference
> frequency lock option fitted and recently purchased a Leo Bodnar GPS
> disciplined reference clock which provides the necessary 10MHz drive for
> the ext ref option. With a new toy you have go to play and what I
> discovered follows.
>
> With the GPS source up and running, turning on the K3 and enabling the
> external ref feature the REF CAL measured TXCO frequency will be
> displayed, counted by the ref lock module. This frequency will be seen
> to change with warm up. My TXCO has a positive drift of approx 26Hz+/- a
> couple in the first three minutes, for the next 30 minutes it drifts a
> further 6Hz. Thereafter it slowly drifts until after four hours it tops
> out at +57Hz or so and by this measurement method stops drifting.
>
> However, there is more. At the same time as noting the REF CAL frequency
> every minute, for the first hour, I also recorded the front panel (FP)
> temperature. This started at 23C and over the measurement period
> increased to 38C. It was observed that the rise in FP temp and the drift
> follow a similar trajectory. As would be expected.
>
> I have monitored the REF CAL frequency for a couple of months now and
> note that the TXCO drift on my unit always maxes out at more or less the
> same reading.
>
> I have reached the conclusion that if at least two hours of warm up are
> allowed and a WWV cal operation is then performed you will be in a
> pretty good place with respect to total drift and subsequent overall
> frequency (dial) accuracy.
>
> It is easy to discover the pattern and extent of the drift of the TXCO
> in your K3 without any external measuring equipment, external ref locks
> or such.
>
> 1. From cold tune to a WWV frequency you will be able to receive
> reliably for a few hours. Higher the better.
> 2. Wait 5 minutes or you will be chasing a moving target.
> 3. Perform a REF CAL and note the reading.
> 4. Perform a REF CAL every half hour, less if you feel like it and note
> the readings.
> 5. Eventually the reading will really slow down and more or less stop
> changing.
> 6. Choose a reading that indicates that the bulk of the drift has
> happened, (1-2 hours)
> 7. Set REF CAL to that reading and sleep well. Good enough for HF.
>
> Given the highest and lowest frequency readings a further experiment can
> be performed to discover the consequences of the TXCO drift on dial
> accuracy. It only takes a few minutes.
>
> 1. Set REF CALL to the lowest recorded frequency and tune the K3 to a
> stable test frequency, I used my XG3, note the "dial" reading in fine
> frequency display, 3 digits after the decimal point. I used the CW auto
> spot feature to do the final tune.
> 2. Set REF CAL to the highest recorded frequency and retune the K3 as
> above noting the "dial" frequency.
>
> The lowest to highest REF CAL frequency is the total TXCO drift in Hz.
> The lowest to highest "dial" frequency will indicate the consequence of
> that TXCO drift in Hz. You will be pleased to note that the two do not
> match. The K3 tuned frequency change is rather less than the TXCO drift.
>
> Reset the REF CAL reading to that you previously chose to be your K3's
> sweat spot.
>
> The above shows why I was wrong in relating the REF CAL frequency
> changes to TXCO ageing. In reality it all comes down to warm up time.
>
> I hope this was worth the read.
>
> Regards,
>
> Mike VP8NO
>
>
>
> On 09/04/2017 05:51, Roger via Elecraft wrote:
>> KREF3MDKT This modification increases the output levels from the KREF3
>> Reference Oscillator to provide proper drive levels for K3 transceivers
>> equipped with a KSYN3A synthesizers the KRX3 or KRX3A sub receiver and
>> the
>> K144XV 2-meter transceiver.
>>
>> 73, Roger
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

gm3sek

Re: K3 slightly off frequency

K3KO wrote:

>With the standard synthesizers, as one tunes up the band the true
>frequency deviates from the displayed by up to +/-4 Hz. There are
times
>when one tunes up and the RX actually goes to a lower frequency. Same
>problem when tuning downwards. In other words, there is electronic
>"backlash". One has no way of knowing which point of this sawtooth
>error curve you are when choosing to calibrate to WWV. This is
>essentially fixed with the new synthesizers.

Back in the day, Elecraft informed us about that cyclical error problem
with the old synthesizer. It would now be good to have a definitive
statement about the frequency setting accuracy in the new synthesizer.

The same applies to the TCXO error correction by the KREF3 module. Since
corrections are applied by rewriting the declared value of the 48MHz
reference frequency, presumably this can still only be changed in 1Hz
increments.

A related question (raised by Don's post, just in) is the magnitude of
any difference between the displayed sidetone pitch and the actual value
within the synthesizer?

73 from Ian GM3SEK

>-----Original Message-----
>From: Elecraft [mailto:[hidden email]] On Behalf Of
>brian
>Sent: 09 April 2017 18:33
>To: [hidden email] >> 'Elecraft Reflector'
>Subject: Re: [Elecraft] K3 slightly off frequency
>
>All true. Note that the standard oscillator takes two hours to stop
>drifting instead of four. Also the TCXO isn't. There is no
temperature
>feedback implemented. One is essentially seeing the stability of the
>native oscillator. Too bad feedback isn't implemented, I'd bet a lot
of
>drift noted would disappear.
>
>Not discussed is the "last digit" syndrome. Only believe the last
digit

>displayed if you can check that it is accurate.
>
>
>73 de Brian/K3KO
>
>
>On 4/9/2017 16:16 PM, Mike Harris wrote:
>> Immediate apologies, this is a tad long but hopefully interesting.
>>
>> My K3 has the new synths (2), K144XV with REF Lock option and all is
>> well without doing the KREF3 modification. I guess this is an it

either
>> works or it don't situation.
>>
>> With respect to the post about off frequency, not a simple answer.
>>
>> Firstly accuracy and resolution or precision are not to be confused,
one
>> doesn't imply the other. The K3 display may read to 1Hz but that
doesn't
>> mean it is accurate to 1Hz. If folks in a net all set their various
>> digital displays to the same frequency it doesn't mean they are all
on
>> the same frequency.
>>
>> As has been mentioned there is a perfectly good method of adjusting
>> calibration detailed in the handbook using WWV. It doesn't directly
tune
>> or otherwise adjust the reference oscillator (TCXO) but lets whatever
is
>> involved with controlling the synths what the reference frequency
really
>> is so that the error can compensated for mathematically. That is my
>> understanding. I have been using this WWV method for the past nine
>years
>> and was convinced that the TXCO was probably drifting with age and
have
>> often said that the CONFIG: REF CAL is not a one off adjustment. This
>> unfortunately turns out not to be the whole story.
>>
>> Now it has to be said, the TXCO does drift, shock, horror. The high
>> stability option is described as being +/-1ppm but actually seems to
>> achieve 0.5ppm, at least mine does. How do I know this? I don't have
a
>> frequency counter, or at least I didn't and in fact you don't need
one
>> as will be discovered later. What I do have is the K3 external
reference
>> frequency lock option fitted and recently purchased a Leo Bodnar GPS
>> disciplined reference clock which provides the necessary 10MHz drive
for
>> the ext ref option. With a new toy you have go to play and what I
>> discovered follows.
>>
>> With the GPS source up and running, turning on the K3 and enabling
the
>> external ref feature the REF CAL measured TXCO frequency will be
>> displayed, counted by the ref lock module. This frequency will be
seen
>> to change with warm up. My TXCO has a positive drift of approx
26Hz+/- a
>> couple in the first three minutes, for the next 30 minutes it drifts
a
>> further 6Hz. Thereafter it slowly drifts until after four hours it
tops
>> out at +57Hz or so and by this measurement method stops drifting.
>>
>> However, there is more. At the same time as noting the REF CAL
frequency
>> every minute, for the first hour, I also recorded the front panel
(FP)
>> temperature. This started at 23C and over the measurement period
>> increased to 38C. It was observed that the rise in FP temp and the
drift
>> follow a similar trajectory. As would be expected.
>>
>> I have monitored the REF CAL frequency for a couple of months now and
>> note that the TXCO drift on my unit always maxes out at more or less
the
>> same reading.
>>
>> I have reached the conclusion that if at least two hours of warm up
are
>> allowed and a WWV cal operation is then performed you will be in a
>> pretty good place with respect to total drift and subsequent overall
>> frequency (dial) accuracy.
>>
>> It is easy to discover the pattern and extent of the drift of the
TXCO
>> in your K3 without any external measuring equipment, external ref
locks
>> or such.
>>
>> 1. From cold tune to a WWV frequency you will be able to receive
>> reliably for a few hours. Higher the better.
>> 2. Wait 5 minutes or you will be chasing a moving target.
>> 3. Perform a REF CAL and note the reading.
>> 4. Perform a REF CAL every half hour, less if you feel like it and
note
>> the readings.
>> 5. Eventually the reading will really slow down and more or less stop
>> changing.
>> 6. Choose a reading that indicates that the bulk of the drift has
>> happened, (1-2 hours)
>> 7. Set REF CAL to that reading and sleep well. Good enough for HF.
>>
>> Given the highest and lowest frequency readings a further experiment
can
>> be performed to discover the consequences of the TXCO drift on dial
>> accuracy. It only takes a few minutes.
>>
>> 1. Set REF CALL to the lowest recorded frequency and tune the K3 to a
>> stable test frequency, I used my XG3, note the "dial" reading in fine
>> frequency display, 3 digits after the decimal point. I used the CW
auto
>> spot feature to do the final tune.
>> 2. Set REF CAL to the highest recorded frequency and retune the K3 as
>> above noting the "dial" frequency.
>>
>> The lowest to highest REF CAL frequency is the total TXCO drift in
Hz.
>> The lowest to highest "dial" frequency will indicate the consequence
of
>> that TXCO drift in Hz. You will be pleased to note that the two do
not
>> match. The K3 tuned frequency change is rather less than the TXCO
drift.
>>
>> Reset the REF CAL reading to that you previously chose to be your
K3's

>> sweat spot.
>>
>> The above shows why I was wrong in relating the REF CAL frequency
>> changes to TXCO ageing. In reality it all comes down to warm up time.
>>
>> I hope this was worth the read.
>>
>> Regards,
>>
>> Mike VP8NO
>>
>>
>>
>> On 09/04/2017 05:51, Roger via Elecraft wrote:
>>> KREF3MDKT This modification increases the output levels from the
>KREF3
>>> Reference Oscillator to provide proper drive levels for K3

transceivers

>>> equipped with a KSYN3A synthesizers the KRX3 or KRX3A sub receiver
>and
>>> the
>>> K144XV 2-meter transceiver.
>>>
>>> 73, Roger
>> ______________________________________________________________
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Michael Walker

Re: K3 slightly off frequency

Watch this

https://youtu.be/_SWRlTUG5RM

You will be able to quickly tell.

Va3mw

> On Apr 9, 2017, at 6:11 PM, Ian White <[hidden email]> wrote:
>
> K3KO wrote:
>
>> With the standard synthesizers, as one tunes up the band the true
>> frequency deviates from the displayed by up to +/-4 Hz. There are
> times
>> when one tunes up and the RX actually goes to a lower frequency. Same
>> problem when tuning downwards. In other words, there is electronic
>> "backlash". One has no way of knowing which point of this sawtooth
>> error curve you are when choosing to calibrate to WWV. This is
>> essentially fixed with the new synthesizers.
>
> Back in the day, Elecraft informed us about that cyclical error problem
> with the old synthesizer. It would now be good to have a definitive
> statement about the frequency setting accuracy in the new synthesizer.
>
> The same applies to the TCXO error correction by the KREF3 module. Since
> corrections are applied by rewriting the declared value of the 48MHz
> reference frequency, presumably this can still only be changed in 1Hz
> increments.
>
> A related question (raised by Don's post, just in) is the magnitude of
> any difference between the displayed sidetone pitch and the actual value
> within the synthesizer?
>
> 73 from Ian GM3SEK
>
>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> brian
>> Sent: 09 April 2017 18:33
>> To: [hidden email] >> 'Elecraft Reflector'
>> Subject: Re: [Elecraft] K3 slightly off frequency
>>
>> All true. Note that the standard oscillator takes two hours to stop
>> drifting instead of four. Also the TCXO isn't. There is no
> temperature
>> feedback implemented. One is essentially seeing the stability of the
>> native oscillator. Too bad feedback isn't implemented, I'd bet a lot
> of
>> drift noted would disappear.
>>
>> Not discussed is the "last digit" syndrome. Only believe the last
> digit
>> displayed if you can check that it is accurate.
>>
>>
>> 73 de Brian/K3KO
>>
>>
>>> On 4/9/2017 16:16 PM, Mike Harris wrote:
>>> Immediate apologies, this is a tad long but hopefully interesting.
>>>
>>> My K3 has the new synths (2), K144XV with REF Lock option and all is
>>> well without doing the KREF3 modification. I guess this is an it
> either
>>> works or it don't situation.
>>>
>>> With respect to the post about off frequency, not a simple answer.
>>>
>>> Firstly accuracy and resolution or precision are not to be confused,
> one
>>> doesn't imply the other. The K3 display may read to 1Hz but that
> doesn't
>>> mean it is accurate to 1Hz. If folks in a net all set their various
>>> digital displays to the same frequency it doesn't mean they are all
> on
>>> the same frequency.
>>>
>>> As has been mentioned there is a perfectly good method of adjusting
>>> calibration detailed in the handbook using WWV. It doesn't directly
> tune
>>> or otherwise adjust the reference oscillator (TCXO) but lets whatever
> is
>>> involved with controlling the synths what the reference frequency
> really
>>> is so that the error can compensated for mathematically. That is my
>>> understanding. I have been using this WWV method for the past nine
>> years
>>> and was convinced that the TXCO was probably drifting with age and
> have
>>> often said that the CONFIG: REF CAL is not a one off adjustment. This
>>> unfortunately turns out not to be the whole story.
>>>
>>> Now it has to be said, the TXCO does drift, shock, horror. The high
>>> stability option is described as being +/-1ppm but actually seems to
>>> achieve 0.5ppm, at least mine does. How do I know this? I don't have
> a
>>> frequency counter, or at least I didn't and in fact you don't need
> one
>>> as will be discovered later. What I do have is the K3 external
> reference
>>> frequency lock option fitted and recently purchased a Leo Bodnar GPS
>>> disciplined reference clock which provides the necessary 10MHz drive
> for
>>> the ext ref option. With a new toy you have go to play and what I
>>> discovered follows.
>>>
>>> With the GPS source up and running, turning on the K3 and enabling
> the
>>> external ref feature the REF CAL measured TXCO frequency will be
>>> displayed, counted by the ref lock module. This frequency will be
> seen
>>> to change with warm up. My TXCO has a positive drift of approx
> 26Hz+/- a
>>> couple in the first three minutes, for the next 30 minutes it drifts
> a
>>> further 6Hz. Thereafter it slowly drifts until after four hours it
> tops
>>> out at +57Hz or so and by this measurement method stops drifting.
>>>
>>> However, there is more. At the same time as noting the REF CAL
> frequency
>>> every minute, for the first hour, I also recorded the front panel
> (FP)
>>> temperature. This started at 23C and over the measurement period
>>> increased to 38C. It was observed that the rise in FP temp and the
> drift
>>> follow a similar trajectory. As would be expected.
>>>
>>> I have monitored the REF CAL frequency for a couple of months now and
>>> note that the TXCO drift on my unit always maxes out at more or less
> the
>>> same reading.
>>>
>>> I have reached the conclusion that if at least two hours of warm up
> are
>>> allowed and a WWV cal operation is then performed you will be in a
>>> pretty good place with respect to total drift and subsequent overall
>>> frequency (dial) accuracy.
>>>
>>> It is easy to discover the pattern and extent of the drift of the
> TXCO
>>> in your K3 without any external measuring equipment, external ref
> locks
>>> or such.
>>>
>>> 1. From cold tune to a WWV frequency you will be able to receive
>>> reliably for a few hours. Higher the better.
>>> 2. Wait 5 minutes or you will be chasing a moving target.
>>> 3. Perform a REF CAL and note the reading.
>>> 4. Perform a REF CAL every half hour, less if you feel like it and
> note
>>> the readings.
>>> 5. Eventually the reading will really slow down and more or less stop
>>> changing.
>>> 6. Choose a reading that indicates that the bulk of the drift has
>>> happened, (1-2 hours)
>>> 7. Set REF CAL to that reading and sleep well. Good enough for HF.
>>>
>>> Given the highest and lowest frequency readings a further experiment
> can
>>> be performed to discover the consequences of the TXCO drift on dial
>>> accuracy. It only takes a few minutes.
>>>
>>> 1. Set REF CALL to the lowest recorded frequency and tune the K3 to a
>>> stable test frequency, I used my XG3, note the "dial" reading in fine
>>> frequency display, 3 digits after the decimal point. I used the CW
> auto
>>> spot feature to do the final tune.
>>> 2. Set REF CAL to the highest recorded frequency and retune the K3 as
>>> above noting the "dial" frequency.
>>>
>>> The lowest to highest REF CAL frequency is the total TXCO drift in
> Hz.
>>> The lowest to highest "dial" frequency will indicate the consequence
> of
>>> that TXCO drift in Hz. You will be pleased to note that the two do
> not
>>> match. The K3 tuned frequency change is rather less than the TXCO
> drift.
>>>
>>> Reset the REF CAL reading to that you previously chose to be your
> K3's
>>> sweat spot.
>>>
>>> The above shows why I was wrong in relating the REF CAL frequency
>>> changes to TXCO ageing. In reality it all comes down to warm up time.
>>>
>>> I hope this was worth the read.
>>>
>>> Regards,
>>>
>>> Mike VP8NO
>>>
>>>
>>>
>>>> On 09/04/2017 05:51, Roger via Elecraft wrote:
>>>> KREF3MDKT This modification increases the output levels from the
>> KREF3
>>>> Reference Oscillator to provide proper drive levels for K3
> transceivers
>>>> equipped with a KSYN3A synthesizers the KRX3 or KRX3A sub receiver
>> and
>>>> the
>>>> K144XV 2-meter transceiver.
>>>>
>>>> 73, Roger
>>> ______________________________________________________________
>>> 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
>>> Message delivered to [hidden email]
>> ______________________________________________________________
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>>
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>> Message delivered to [hidden email]
>
> ______________________________________________________________
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