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K3(s) main oscillator calibration

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hdv

K3(s) main oscillator calibration

Hi all,

In the CONFIG menu REF CALL the value of the main oscillator can be set.

However, this does not impact the TCXO frequency at all in a direct sense.

Whatever the REF CALL value, the TXCO frequency stays the same.

This can also be seen in the schematic.

The TXCO just outputs 49.380 MHz and has no voltage/frequency-adjustment
input.

So where and how does the frequency correction take place?

Somewhere at the 15 kHz level or in the KSYN3 DDS / KSYN3A divider?

Who can explain the principle.

73 Henk

PA0C

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Wes Stewart-2

Re: K3(s) main oscillator calibration

The various reference calibration methods, including direct measurement of the
TCXO that I do, just determine what the actual reference frequency is, but don't
change it.

This value is then used internally to compute the correct frequencies.

Wes N7WS

On 6/6/2020 11:47 AM, [hidden email] wrote:

> Hi all,
>
>
>
> In the CONFIG menu REF CALL the value of the main oscillator can be set.
>
> However, this does not impact the TCXO frequency at all in a direct sense.
>
>
>
> Whatever the REF CALL value, the TXCO frequency stays the same.
>
> This can also be seen in the schematic.
>
> The TXCO just outputs 49.380 MHz and has no voltage/frequency-adjustment
> input.
>
>
>
> So where and how does the frequency correction take place?
>
> Somewhere at the 15 kHz level or in the KSYN3 DDS / KSYN3A divider?
>
>
>
> Who can explain the principle.
>
>
>
> 73 Henk
>
> PA0C
>
>
>

w4sc-2

Re: K3(s) main oscillator calibration

In reply to this post by hdv

I like the zero beat WWV method. Used it in the Navy to calibrate / PM the 10MHz frequency standards aboard ship. Requires the least amount of test equipment! If you can receive WWV on 20MHz to calibrate the K3/K3S, all the better,

Using a frequency counter I would think 0.1Hz resolution and attending accuracy would be in order, plus an accurate time base in the counter, GPS locked,,, or oven-ized, on all the time reference ,,, ect.

Ben W4SC

Sent from Mail for Windows 10

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W2xj

Re: K3(s) main oscillator calibration

the problem with WWV is doppler shift.

Sent from my iPad

> On Jun 6, 2020, at 5:27 PM, w4sc <[hidden email]> wrote:
>
> I like the zero beat WWV method. Used it in the Navy to calibrate / PM the 10MHz frequency standards aboard ship. Requires the least amount of test equipment! If you can receive WWV on 20MHz to calibrate the K3/K3S, all the better,
>
> Using a frequency counter I would think 0.1Hz resolution and attending accuracy would be in order, plus an accurate time base in the counter, GPS locked,,, or oven-ized, on all the time reference ,,, ect.
>
> Ben W4SC
>
>
> Sent from Mail for Windows 10
>
> ______________________________________________________________
> 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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>

NK7Z

Re: K3(s) main oscillator calibration

Hi,

As the other station siad, you will have Doppler issues. Also the K3
tunes in steps, which make sustained .1 hz accuracy a dream, not
attainable. It looks to tune in .25 Hz., or larger steps. I am going
from memory here, so it may be something different.

I wanted to use my K3 to watch Ionospheric shifting, via Doppler shifts,
from WWV. I am unable to as a result of the method Elecraft chose for
tuning.

I have the TXCO, and that just provides a reference for the radio, it
does not make the steps go away...

I was quite disappointed when I discovered this, but, the good stuff in
the rest of the radio makes up for that small loss. I'll buy some
stable rig that uses analog tuning.

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources

On 6/6/20 2:31 PM, W2xj wrote:

> the problem with WWV is doppler shift.
>
> Sent from my iPad
>
>> On Jun 6, 2020, at 5:27 PM, w4sc <[hidden email]> wrote:
>>
>> I like the zero beat WWV method. Used it in the Navy to calibrate / PM the 10MHz frequency standards aboard ship. Requires the least amount of test equipment! If you can receive WWV on 20MHz to calibrate the K3/K3S, all the better,
>>
>> Using a frequency counter I would think 0.1Hz resolution and attending accuracy would be in order, plus an accurate time base in the counter, GPS locked,,, or oven-ized, on all the time reference ,,, ect.
>>
>> Ben W4SC
>>
>>
>> Sent from Mail for Windows 10
>>
>> ______________________________________________________________
>> 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]
>>
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

Don Wilhelm

Re: K3(s) main oscillator calibration

With the main K3 fine tuning at 1 Hz steps, I don't know that 0.1Hz or
even 0.25Hz doppler shift will matter much in the final result.

My frequency counter is good to 10 exp-9 which equates to +/-0.1 Hz at
the TCXO frequency, so the WWV method provides as good or better
accuracy, even considering the doppler shift possibility.

The main problem is chasing the beat note down to a stable solid note.
You usually can't truly get there, but you can get close enough that you
hear about 10 or 20 seconds between peaks. Close enough for me.

It can be quite expensive to obtain stability better than the K3S in an
analog oscillator. My HP8640B signal generator will do that, but it
takes at least a 3 hour warmup before it becomes stable. Yes, all the
internal enclosures in my '8640 have covers with all the screws
installed - that helps. OK, that is 'old iron', but I am not going to
spend several $10,000 for something better. I have better things to do
with my money, and no longer have access to modern lab quality equipment
to achieve that kind of stability.

We have a ham band transceiver - not a precision lab instrument. As
long as we can stay inside our ham bands, that is all that matters to
me. I would not put a carrier exactly on 7,000.00 kHz with any transceiver.

73,
Don W3FPR

On 6/6/2020 5:42 PM, Dave Cole wrote:

> Hi,
>
> As the other station siad, you will have Doppler issues. Also the K3
> tunes in steps, which make sustained .1 hz accuracy a dream, not
> attainable. It looks to tune in .25 Hz., or larger steps. I am going
> from memory here, so it may be something different.
>
> I wanted to use my K3 to watch Ionospheric shifting, via Doppler shifts,
> from WWV. I am unable to as a result of the method Elecraft chose for
> tuning.
>
> I have the TXCO, and that just provides a reference for the radio, it
> does not make the steps go away...
>
> I was quite disappointed when I discovered this, but, the good stuff in
> the rest of the radio makes up for that small loss. I'll buy some
> stable rig that uses analog tuning.
>

Wes Stewart-2

Re: K3(s) main oscillator calibration

In reply to this post by NK7Z

All synthesized radios tune in steps. The difference between them is some are
smaller steps than others. Eleven years ago I offered a fourth method for
calibrating the reference frequency in a K3. (I suspect, but do not know that
the K3S is different.) See:
http://elecraft.365791.n2.nabble.com/Ref-Osc-Cal-Method-4-td2595451.html

After reading about my observations another ham queried Wayne and he responded
with an explanation of the frequency generation in the K3. Once again, I don't
whether this applies to the K3S. Perhaps Wayne will let us know. Nevertheless,
the tuning step sizes are different for different bands with the higher bands
having greater step sizes, i.e. less accuracy. I-F BW/Shift requires changing
oscillator frequencies at I-F ("BFO") with commensurate changes in the LO.
Since the LO has different step sizes on different bands, changes in the beat
note (that I observed) do occur.

The K3(S) is a great transceiver, it isn't a great frequency meter.

Wes N7WS

On 6/6/2020 2:42 PM, Dave Cole wrote:

> Hi,
>
> As the other station siad, you will have Doppler issues. Also the K3 tunes in
> steps, which make sustained .1 hz accuracy a dream, not attainable. It looks
> to tune in .25 Hz., or larger steps. I am going from memory here, so it may
> be something different.
>
> I wanted to use my K3 to watch Ionospheric shifting, via Doppler shifts, from
> WWV. I am unable to as a result of the method Elecraft chose for tuning.
>
> I have the TXCO, and that just provides a reference for the radio, it does not
> make the steps go away...
>
> I was quite disappointed when I discovered this, but, the good stuff in the
> rest of the radio makes up for that small loss. I'll buy some stable rig that
> uses analog tuning.
>
> 73, and thanks,
> Dave (NK7Z)
> https://www.nk7z.net
> ARRL Volunteer Examiner
> ARRL Technical Specialist
> ARRL Asst. Director, NW Division, Technical Resources

Bob McGraw - K4TAX

Re: K3(s) main oscillator calibration

In reply to this post by Don Wilhelm

From my take, it is "ham radio" therefore +/-1 Hz. should be good
enough for most operations. After all, the K3S resolution is 1 Hz.,
+/-1 count as I see it. I can keep mine +/-2 or 3 Hz on most bands.

I use WWV with the radio in CW mode and CWT on, tune close to WWV and
press SPOT.    If it settles on the WWV frequency that's good. If it is
off a few Hz, then I tweak the REF CAL up or down a few Hz until I get
the accuracy I wish by repeating the process several times. Still I
find +/- 1 Hz is about it, even with the high stability TXCO and very
adequate warm-up time of about 2 hrs.

If one needs something more accurate, then Don is correct, test
equipment is the way to go. And expect to spend big bucks for good
quality equipment that IS traceable to NIST.   If the NIST document or
calibration is more than 1 year old, the results will be questionable.

I wrote an article which was published in QST, Sept 2015.   It deals
with "Transmit and Receive On Frequency". It shows that digital
readouts are just that, readouts, and they are not frequency
determining or measuring circuits.    And when it is accurate on one
band it may not have the same accuracy on another band.

73

Bob, K4TAX

On 6/6/2020 5:20 PM, Don Wilhelm wrote:

> With the main K3 fine tuning at 1 Hz steps, I don't know that 0.1Hz or
> even 0.25Hz doppler shift will matter much in the final result.
>
> My frequency counter is good to 10 exp-9 which equates to +/-0.1 Hz at
> the TCXO frequency, so the WWV method provides as good or better
> accuracy, even considering the doppler shift possibility.
>
> The main problem is chasing the beat note down to a stable solid note.
> You usually can't truly get there, but you can get close enough that
> you hear about 10 or 20 seconds between peaks. Close enough for me.
>
> It can be quite expensive to obtain stability better than the K3S in
> an analog oscillator. My HP8640B signal generator will do that, but
> it takes at least a 3 hour warmup before it becomes stable. Yes, all
> the internal enclosures in my '8640 have covers with all the screws
> installed - that helps. OK, that is 'old iron', but I am not going to
> spend several $10,000 for something better. I have better things to
> do with my money, and no longer have access to modern lab quality
> equipment to achieve that kind of stability.
>
> We have a ham band transceiver - not a precision lab instrument. As
> long as we can stay inside our ham bands, that is all that matters to
> me. I would not put a carrier exactly on 7,000.00 kHz with any
> transceiver.
>
> 73,
> Don W3FPR
>
>

NK7Z

Re: K3(s) main oscillator calibration

In reply to this post by Wes Stewart-2

Thanks for the info, I think the other ham that asked Wayne, was me...
:) I don't need absolute accuracy, I just wanted no steps is all... I
will go pick up an older Icom, or something along that line. I had a
Pro III and it worked for my application, watching short term changes in
the Ionosphere. Even had I know the K3 was not capable of doing this, I
would have still purchased it. As you intimated, the right tool for the
right job.

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources

On 6/6/20 6:48 PM, Wes wrote:

> All synthesized radios tune in steps. The difference between them is
> some are smaller steps than others. Eleven years ago I offered a fourth
> method for calibrating the reference frequency in a K3. (I suspect, but
> do not know that the K3S is different.) See:
> http://elecraft.365791.n2.nabble.com/Ref-Osc-Cal-Method-4-td2595451.html
>
> After reading about my observations another ham queried Wayne and he
> responded with an explanation of the frequency generation in the K3.
> Once again, I don't whether this applies to the K3S. Perhaps Wayne will
> let us know. Nevertheless, the tuning step sizes are different for
> different bands with the higher bands having greater step sizes, i.e.
> less accuracy. I-F BW/Shift requires changing oscillator frequencies at
> I-F ("BFO") with commensurate changes in the LO. Since the LO has
> different step sizes on different bands, changes in the beat note (that
> I observed) do occur.
>
> The K3(S) is a great transceiver, it isn't a great frequency meter.
>
> Wes N7WS
>
> On 6/6/2020 2:42 PM, Dave Cole wrote:
>> Hi,
>>
>> As the other station siad, you will have Doppler issues. Also the K3
>> tunes in steps, which make sustained .1 hz accuracy a dream, not
>> attainable. It looks to tune in .25 Hz., or larger steps. I am going
>> from memory here, so it may be something different.
>>
>> I wanted to use my K3 to watch Ionospheric shifting, via Doppler
>> shifts, from WWV. I am unable to as a result of the method Elecraft
>> chose for tuning.
>>
>> I have the TXCO, and that just provides a reference for the radio, it
>> does not make the steps go away...
>>
>> I was quite disappointed when I discovered this, but, the good stuff
>> in the rest of the radio makes up for that small loss. I'll buy some
>> stable rig that uses analog tuning.
>>
>> 73, and thanks,
>> Dave (NK7Z)
>> https://www.nk7z.net
>> ARRL Volunteer Examiner
>> ARRL Technical Specialist
>> ARRL Asst. Director, NW Division, Technical Resources
>
> ______________________________________________________________
> 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]

hdv

Re: K3(s) main oscillator calibration

In reply to this post by Wes Stewart-2

I have seen a lot of answers.
These are all true, but what is the exact way of working.

73 Henk

-----Oorspronkelijk bericht-----
Van: [hidden email] <[hidden email]> Namens Wes
Verzonden: zaterdag 6 juni 2020 21:22
Aan: [hidden email]
Onderwerp: Re: [Elecraft] K3(s) main oscillator calibration

The various reference calibration methods, including direct measurement of the TCXO that I do, just determine what the actual reference frequency is, but don't change it.

This value is then used internally to compute the correct frequencies.

Wes N7WS

On 6/6/2020 11:47 AM, [hidden email] wrote:

> Hi all,
>
>
>
> In the CONFIG menu REF CALL the value of the main oscillator can be set.
>
> However, this does not impact the TCXO frequency at all in a direct sense.
>
>
>
> Whatever the REF CALL value, the TXCO frequency stays the same.
>
> This can also be seen in the schematic.
>
> The TXCO just outputs 49.380 MHz and has no
> voltage/frequency-adjustment input.
>
>
>
> So where and how does the frequency correction take place?
>
> Somewhere at the 15 kHz level or in the KSYN3 DDS / KSYN3A divider?
>
>
>
> Who can explain the principle.
>
>
>
> 73 Henk
>
> PA0C
>
>
>

______________________________________________________________
Elecraft mailing list
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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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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Message delivered to [hidden email]

Randy Farmer-2

Re: K3(s) main oscillator calibration

In reply to this post by Bob McGraw - K4TAX

The best way I've found to calibrate the K3 reference oscillator is to
use the 500 Hz and 600 Hz audio tones transmitted by WWV. I put the line
out audio through a sound card and look at it with SpectrumLab. Tune in
WWV in USB or LSB mode and tweak the reference trim until the tones are
correct when you switch sidebands with the dial at precisely XX.000 000
MHz. I've found that you can't get precise agreement between sidebands,
probably because of quantization limits in the synthesizer, but it will
certainly be less than a couple of Hertz. This is plenty accurate for
amateur (or probably any other kind) of service.

73...
Randy, W8FN

On 6/6/2020 10:20 PM, Bob McGraw K4TAX wrote:

> From my take, it is "ham radio" therefore +/-1 Hz. should be good
> enough for most operations. After all, the K3S resolution is 1 Hz.,
> +/-1 count as I see it. I can keep mine +/-2 or 3 Hz on most bands.
>
> I use WWV with the radio in CW mode and CWT on, tune close to WWV and
> press SPOT.    If it settles on the WWV frequency that's good. If it
> is off a few Hz, then I tweak the REF CAL up or down a few Hz until I
> get the accuracy I wish by repeating the process several times. Still
> I find +/- 1 Hz is about it, even with the high stability TXCO and
> very adequate warm-up time of about 2 hrs.
>
> If one needs something more accurate, then Don is correct, test
> equipment is the way to go. And expect to spend big bucks for good
> quality equipment that IS traceable to NIST.   If the NIST document or
> calibration is more than 1 year old, the results will be questionable.
>
> I wrote an article which was published in QST, Sept 2015.   It deals
> with "Transmit and Receive On Frequency". It shows that digital
> readouts are just that, readouts, and they are not frequency
> determining or measuring circuits.    And when it is accurate on one
> band it may not have the same accuracy on another band.
>
> 73
>
> Bob, K4TAX
>
>
> On 6/6/2020 5:20 PM, Don Wilhelm wrote:
>> With the main K3 fine tuning at 1 Hz steps, I don't know that 0.1Hz
>> or even 0.25Hz doppler shift will matter much in the final result.
>>
>> My frequency counter is good to 10 exp-9 which equates to +/-0.1 Hz
>> at the TCXO frequency, so the WWV method provides as good or better
>> accuracy, even considering the doppler shift possibility.
>>
>> The main problem is chasing the beat note down to a stable solid
>> note. You usually can't truly get there, but you can get close enough
>> that you hear about 10 or 20 seconds between peaks. Close enough for me.
>>
>> It can be quite expensive to obtain stability better than the K3S in
>> an analog oscillator. My HP8640B signal generator will do that, but
>> it takes at least a 3 hour warmup before it becomes stable. Yes, all
>> the internal enclosures in my '8640 have covers with all the screws
>> installed - that helps. OK, that is 'old iron', but I am not going
>> to spend several $10,000 for something better. I have better things
>> to do with my money, and no longer have access to modern lab quality
>> equipment to achieve that kind of stability.
>>
>> We have a ham band transceiver - not a precision lab instrument. As
>> long as we can stay inside our ham bands, that is all that matters to
>> me. I would not put a carrier exactly on 7,000.00 kHz with any
>> transceiver.
>>
>> 73,
>> Don W3FPR

Wes Stewart-2

Re: K3(s) main oscillator calibration

If you look at my earlier message in this thread, you'll see the link to nabble
and my post from 11 years ago where I describe this method. :-)

Wes N7WS

On 6/7/2020 6:03 AM, Randy Farmer wrote:

> The best way I've found to calibrate the K3 reference oscillator is to use the
> 500 Hz and 600 Hz audio tones transmitted by WWV. I put the line out audio
> through a sound card and look at it with SpectrumLab. Tune in WWV in USB or
> LSB mode and tweak the reference trim until the tones are correct when you
> switch sidebands with the dial at precisely XX.000 000 MHz. I've found that
> you can't get precise agreement between sidebands, probably because of
> quantization limits in the synthesizer, but it will certainly be less than a
> couple of Hertz. This is plenty accurate for amateur (or probably any other
> kind) of service.
>
> 73...
> Randy, W8FN
>
> On 6/6/2020 10:20 PM, Bob McGraw K4TAX wrote:
>> From my take, it is "ham radio" therefore +/-1 Hz. should be good enough for
>> most operations. After all, the K3S resolution is 1 Hz., +/-1 count as I see
>> it. I can keep mine +/-2 or 3 Hz on most bands.
>>
>> I use WWV with the radio in CW mode and CWT on, tune close to WWV and press
>> SPOT.    If it settles on the WWV frequency that's good. If it is off a few
>> Hz, then I tweak the REF CAL up or down a few Hz until I get the accuracy I
>> wish by repeating the process several times. Still I find +/- 1 Hz is about
>> it, even with the high stability TXCO and very adequate warm-up time of about
>> 2 hrs.
>>
>> If one needs something more accurate, then Don is correct, test equipment is
>> the way to go. And expect to spend big bucks for good quality equipment that
>> IS traceable to NIST.   If the NIST document or calibration is more than 1
>> year old, the results will be questionable.
>>
>> I wrote an article which was published in QST, Sept 2015.   It deals with
>> "Transmit and Receive On Frequency". It shows that digital readouts are just
>> that, readouts, and they are not frequency determining or measuring
>> circuits.    And when it is accurate on one band it may not have the same
>> accuracy on another band.
>>
>> 73
>>
>> Bob, K4TAX
>>
>>
>> On 6/6/2020 5:20 PM, Don Wilhelm wrote:
>>> With the main K3 fine tuning at 1 Hz steps, I don't know that 0.1Hz or even
>>> 0.25Hz doppler shift will matter much in the final result.
>>>
>>> My frequency counter is good to 10 exp-9 which equates to +/-0.1 Hz at the
>>> TCXO frequency, so the WWV method provides as good or better accuracy, even
>>> considering the doppler shift possibility.
>>>
>>> The main problem is chasing the beat note down to a stable solid note. You
>>> usually can't truly get there, but you can get close enough that you hear
>>> about 10 or 20 seconds between peaks. Close enough for me.
>>>
>>> It can be quite expensive to obtain stability better than the K3S in an
>>> analog oscillator. My HP8640B signal generator will do that, but it takes
>>> at least a 3 hour warmup before it becomes stable. Yes, all the internal
>>> enclosures in my '8640 have covers with all the screws installed - that
>>> helps. OK, that is 'old iron', but I am not going to spend several $10,000
>>> for something better. I have better things to do with my money, and no
>>> longer have access to modern lab quality equipment to achieve that kind of
>>> stability.
>>>
>>> We have a ham band transceiver - not a precision lab instrument. As long as
>>> we can stay inside our ham bands, that is all that matters to me. I would
>>> not put a carrier exactly on 7,000.00 kHz with any transceiver.
>>>
>>> 73,
>>> Don W3FPR
> ______________________________________________________________
> 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]

Wes Stewart-2

Re: K3(s) main oscillator calibration

In reply to this post by NK7Z

You might have, but you're not who I'm thinking of:-)

On 6/6/2020 7:45 PM, Dave Cole wrote:
> Thanks for the info, I think the other ham that asked Wayne, was me... :)
______________________________________________________________
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w4sc-2

Re: K3(s) main oscillator calibration

In reply to this post by W2xj

How much doppler shift should be expected?

Sent from Mail for Windows 10

From: W2xj
Sent: Saturday, June 6, 2020 5:31 PM
To: w4sc
Cc: [hidden email]; [hidden email]
Subject: Re: [Elecraft] K3(s) main oscillator calibration

the problem with WWV is doppler shift.

Sent from my iPad

Bob McGraw - K4TAX

Re: K3(s) main oscillator calibration

In referencing TF.NIST.GOV on page 251, I find it stated;

"When high accuracy is not required, probably and fastest way of
comparing the frequency of an oscillator to a broadcast standard is the
familiar heterodyne or zero beat method. "

And then on page 253, I find it stated;

" Usually, however, it is difficult to adjust an oscillator to exactly
zero beat with an HF carrier beyond the ground wave range of the
transmitter. The problem arises from rapid fluctuations in the received
signal strength and from propagation flutter in the received frequency."

References are: THE USES AND LIMITATION OF HF STANDARD BROADCAST FOR
TIME AND FREQUENCY COMPARISON. John T. Stanley, NIST.

As I indicated earlier, a frequency accuracy of +/- 1 Hz for ham radio
purposes is adequate. Likewise for time accuracy +/- 0.1 second is
adequate.

73

Bob, K4TAX

On 6/10/2020 11:52 AM, w4sc wrote:

> How much doppler shift should be expected?
>
> Sent from Mail for Windows 10
>
> From: W2xj
> Sent: Saturday, June 6, 2020 5:31 PM
> To: w4sc
> Cc: [hidden email]; [hidden email]
> Subject: Re: [Elecraft] K3(s) main oscillator calibration
>
> the problem with WWV is doppler shift.
>
> Sent from my iPad
>
>> On Jun 6, 2020, at 5:27 PM, w4sc <[hidden email]> wrote:
>>
>> I like the zero beat WWV method. Used it in the Navy to calibrate / PM the 10MHz frequency standards aboard ship. Requires the least amount of test equipment! If you can receive WWV on 20MHz to calibrate the K3/K3S, all the better,
>>
>> Using a frequency counter I would think 0.1Hz resolution and attending accuracy would be in order, plus an accurate time base in the counter, GPS locked,,, or oven-ized, on all the time reference ,,, ect.
>>
>> Ben W4SC
>>
>>
>> Sent from Mail for Windows 10
>>
>> ______________________________________________________________
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W2xj

Re: K3(s) main oscillator calibration

adequate is not perfect. YMMV

Sent from my iPad

> On Jun 10, 2020, at 2:07 PM, Bob McGraw K4TAX <[hidden email]> wrote:
>
> In referencing TF.NIST.GOV on page 251, I find it stated;
>
> "When high accuracy is not required, probably and fastest way of comparing the frequency of an oscillator to a broadcast standard is the familiar heterodyne or zero beat method. "
>
> And then on page 253, I find it stated;
>
> " Usually, however, it is difficult to adjust an oscillator to exactly zero beat with an HF carrier beyond the ground wave range of the transmitter. The problem arises from rapid fluctuations in the received signal strength and from propagation flutter in the received frequency."
>
> References are: THE USES AND LIMITATION OF HF STANDARD BROADCAST FOR TIME AND FREQUENCY COMPARISON. John T. Stanley, NIST.
>
> As I indicated earlier, a frequency accuracy of +/- 1 Hz for ham radio purposes is adequate. Likewise for time accuracy +/- 0.1 second is adequate.
>
> 73
>
> Bob, K4TAX
>
>
>> On 6/10/2020 11:52 AM, w4sc wrote:
>> How much doppler shift should be expected?
>>
>> Sent from Mail for Windows 10
>>
>> From: W2xj
>> Sent: Saturday, June 6, 2020 5:31 PM
>> To: w4sc
>> Cc: [hidden email]; [hidden email]
>> Subject: Re: [Elecraft] K3(s) main oscillator calibration
>>
>> the problem with WWV is doppler shift.
>>
>> Sent from my iPad
>>
>>>> On Jun 6, 2020, at 5:27 PM, w4sc <[hidden email]> wrote:
>>>
>>> I like the zero beat WWV method. Used it in the Navy to calibrate / PM the 10MHz frequency standards aboard ship. Requires the least amount of test equipment! If you can receive WWV on 20MHz to calibrate the K3/K3S, all the better,
>>>
>>> Using a frequency counter I would think 0.1Hz resolution and attending accuracy would be in order, plus an accurate time base in the counter, GPS locked,,, or oven-ized, on all the time reference ,,, ect.
>>>
>>> Ben W4SC
>>>
>>>
>>> Sent from Mail for Windows 10
>>>
>>> ______________________________________________________________
>>> 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]
>>>
>>
>> ______________________________________________________________
>> 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]
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

Bob McGraw - K4TAX

Re: K3(s) main oscillator calibration

And perfect will never occur. So one best think of adequate.

73

Bob, K4TAX

On 6/10/2020 1:42 PM, W2xj wrote:

> adequate is not perfect. YMMV
>
> Sent from my iPad
>
>> On Jun 10, 2020, at 2:07 PM, Bob McGraw K4TAX <[hidden email]> wrote:
>>
>> In referencing TF.NIST.GOV on page 251, I find it stated;
>>
>> "When high accuracy is not required, probably and fastest way of comparing the frequency of an oscillator to a broadcast standard is the familiar heterodyne or zero beat method."
>>
>> And then on page 253, I find it stated;
>>
>> " Usually, however, it is difficult to adjust an oscillator to exactly zero beat with an HF carrier beyond the ground wave range of the transmitter. The problem arises from rapid fluctuations in the received signal strength and from propagation flutter in the received frequency."
>>
>> References are: THE USES AND LIMITATION OF HF STANDARD BROADCAST FOR TIME AND FREQUENCY COMPARISON. John T. Stanley, NIST.
>>
>> As I indicated earlier, a frequency accuracy of +/- 1 Hz for ham radio purposes is adequate. Likewise for time accuracy +/- 0.1 second is adequate.
>>
>> 73
>>
>> Bob, K4TAX
>>
>>
>>> On 6/10/2020 11:52 AM, w4sc wrote:
>>> How much doppler shift should be expected?
>>>
>>> Sent from Mail for Windows 10
>>>
>>> From: W2xj
>>> Sent: Saturday, June 6, 2020 5:31 PM
>>> To: w4sc
>>> Cc: [hidden email]; [hidden email]
>>> Subject: Re: [Elecraft] K3(s) main oscillator calibration
>>>
>>> the problem with WWV is doppler shift.
>>>
>>> Sent from my iPad
>>>
>>>>> On Jun 6, 2020, at 5:27 PM, w4sc <[hidden email]> wrote:
>>>> I like the zero beat WWV method. Used it in the Navy to calibrate / PM the 10MHz frequency standards aboard ship. Requires the least amount of test equipment! If you can receive WWV on 20MHz to calibrate the K3/K3S, all the better,
>>>>
>>>> Using a frequency counter I would think 0.1Hz resolution and attending accuracy would be in order, plus an accurate time base in the counter, GPS locked,,, or oven-ized, on all the time reference ,,, ect.
>>>>
>>>> Ben W4SC
>>>>
>>>>
>>>> Sent from Mail for Windows 10
>>>>
>>>> ______________________________________________________________
>>>> 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]
>>>>
>>> ______________________________________________________________
>>> 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]
>> ______________________________________________________________
>> 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]
>

W2xj

Re: K3(s) main oscillator calibration

I have higher standards and always have.

Sent from my iPad

> On Jun 10, 2020, at 2:45 PM, Bob McGraw K4TAX <[hidden email]> wrote:
>
> And perfect will never occur. So one best think of adequate.
>
> 73
>
> Bob, K4TAX
>
>> On 6/10/2020 1:42 PM, W2xj wrote:
>> adequate is not perfect. YMMV
>>
>> Sent from my iPad
>>
>>>> On Jun 10, 2020, at 2:07 PM, Bob McGraw K4TAX <[hidden email]> wrote:
>>>
>>> In referencing TF.NIST.GOV on page 251, I find it stated;
>>>
>>> "When high accuracy is not required, probably and fastest way of comparing the frequency of an oscillator to a broadcast standard is the familiar heterodyne or zero beat method."
>>>
>>> And then on page 253, I find it stated;
>>>
>>> " Usually, however, it is difficult to adjust an oscillator to exactly zero beat with an HF carrier beyond the ground wave range of the transmitter. The problem arises from rapid fluctuations in the received signal strength and from propagation flutter in the received frequency."
>>>
>>> References are: THE USES AND LIMITATION OF HF STANDARD BROADCAST FOR TIME AND FREQUENCY COMPARISON. John T. Stanley, NIST.
>>>
>>> As I indicated earlier, a frequency accuracy of +/- 1 Hz for ham radio purposes is adequate. Likewise for time accuracy +/- 0.1 second is adequate.
>>>
>>> 73
>>>
>>> Bob, K4TAX
>>>
>>>
>>>> On 6/10/2020 11:52 AM, w4sc wrote:
>>>> How much doppler shift should be expected?
>>>>
>>>> Sent from Mail for Windows 10
>>>>
>>>> From: W2xj
>>>> Sent: Saturday, June 6, 2020 5:31 PM
>>>> To: w4sc
>>>> Cc: [hidden email]; [hidden email]
>>>> Subject: Re: [Elecraft] K3(s) main oscillator calibration
>>>>
>>>> the problem with WWV is doppler shift.
>>>>
>>>> Sent from my iPad
>>>>
>>>>>> On Jun 6, 2020, at 5:27 PM, w4sc <[hidden email]> wrote:
>>>>> I like the zero beat WWV method. Used it in the Navy to calibrate / PM the 10MHz frequency standards aboard ship. Requires the least amount of test equipment! If you can receive WWV on 20MHz to calibrate the K3/K3S, all the better,
>>>>>
>>>>> Using a frequency counter I would think 0.1Hz resolution and attending accuracy would be in order, plus an accurate time base in the counter, GPS locked,,, or oven-ized, on all the time reference ,,, ect.
>>>>>
>>>>> Ben W4SC
>>>>>
>>>>>
>>>>> Sent from Mail for Windows 10
>>>>>
>>>>> ______________________________________________________________
>>>>> 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]
>>>>>
>>>> ______________________________________________________________
>>>> 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]
>>> ______________________________________________________________
>>> 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]
>>
>
>

w4sc-2

Re: K3(s) main oscillator calibration

In reply to this post by hdv

I agree 100%. However, the implication for using it for the reference oscillator calibration was / could be perceived as not a good way.

John N8UR did an interesting study on the effects.

https://www.febo.com/pages/hf_stability/

73 Ben W4SC

Sent from Mail for Windows 10

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