Elecraft

Display frequency calibration

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Jack Berry

Display frequency calibration

I have s/n 3012, factory built. On a few occassions I have been told by a QSO partner that I am tuned a bit high. It has happened infrequently but I decided to check against WWV.

Three questions:
1) is comparing to WWV a good method to confirm display accuracy? I used my P3 display to center the carrier at 2.5, 5.0, 10.0, 15.0 mHz. The centered carrier spike showed these offsets per WWV transmission;
2.500mHz centered at       2.499.962
5.000mHz centered at       4.999.972
10.000mHz centered at     9.999.984
15.000mHz centered at   14.999.995

2) If there is a better reference outside a lab, what is it?

3) And what is the procedure for correcting a frequency display error? I can't seem to find it in any of the manuals I have.

Thanks!Jack - WE5ST
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Don Wilhelm-4

Re: K3 Display frequency calibration

Jack,

Check page 50 of the manual. I suggest using Method 2. Use the highest
frequency WWV that you can reliably receive, and make certain you are
zero beating with the carrier instead of one of the transmitted tones.

73,
Don W3FPR

On 10/4/2012 10:22 PM, Jack Berry wrote:

> I have s/n 3012, factory built. On a few occassions I have been told by a QSO partner that I am tuned a bit high. It has happened infrequently but I decided to check against WWV.
>
> Three questions:
> 1) is comparing to WWV a good method to confirm display accuracy? I used my P3 display to center the carrier at 2.5, 5.0, 10.0, 15.0 mHz. The centered carrier spike showed these offsets per WWV transmission;
> 2.500mHz centered at 2.499.962
> 5.000mHz centered at 4.999.972
> 10.000mHz centered at 9.999.984
> 15.000mHz centered at 14.999.995
>
> 2) If there is a better reference outside a lab, what is it?
>
> 3) And what is the procedure for correcting a frequency display error? I can't seem to find it in any of the manuals I have.
>
> Thanks!Jack - WE5ST
> ______________________________________________________________
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Jack Berry

Re: K3 Display frequency calibration

Thanks Don! Don't know how I missed that but I did.

God Bless & Best 73!
Jack - WE5ST

________________________________
From: Don Wilhelm <[hidden email]>
To: Jack Berry <[hidden email]>
Cc: "[hidden email]" <[hidden email]>
Sent: Thursday, October 4, 2012 9:31 PM
Subject: Re: [Elecraft] K3 Display frequency calibration

Jack,

Check page 50 of the manual. I suggest using Method 2. Use the highest frequency WWV that you can reliably receive, and make certain you are zero beating with the carrier instead of one of the transmitted tones.

73,
Don W3FPR

On 10/4/2012 10:22 PM, Jack Berry wrote:

> I have s/n 3012, factory built. On a few occassions I have been told by a QSO partner that I am tuned a bit high. It has happened infrequently but I decided to check against WWV.
> Three questions:
> 1) is comparing to WWV a good method to confirm display accuracy? I used my P3 display to center the carrier at 2.5, 5.0, 10.0, 15.0 mHz. The centered carrier spike showed these offsets per WWV transmission;
> 2.500mHz centered at 2.499.962
> 5.000mHz centered at 4.999.972
> 10.000mHz centered at 9.999.984
> 15.000mHz centered at 14.999.995
> 2) If there is a better reference outside a lab, what is it?
> 3) And what is the procedure for correcting a frequency display error? I can't seem to find it in any of the manuals I have.
> Thanks!Jack - WE5ST
> ______________________________________________________________
> 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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> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

KD7PY

Re: Display frequency calibration

In reply to this post by Jack Berry

I use a program called Spectran ( freeware ) which will display the audio frequency of the output of the K3
I set the Frequency of the K3 to 9999.000 kc (usb) this will produce a 1kc tone to the sound card in the computer when tuned to WWV at 10 mhz

Spectran will then display the frequency of that audio tone on the screen.

I then go into the K3 confg menu to REF CAL and adjust it so that the display on Spectran is as close to
1000 cycles ( 1kc ) as possible,
the best I can set the K3 to is with in .27 of a cycle. it does vary between 5 mhz, 10 mhz @ 15 mhz though but not that much.
that is close enough for me.

also I find my self tuning in a station so there is a bit more highs to the sound which will also offset my tnx freq,.... guess I need to use the RIT more..
fwiw
Ed

KD7PY

Re: Display frequency calibration

Just another note: My K3 will not produce a audio tone below 200 cycles in the speaker.. ( could be my ears) so finding a zero beat is impossible as I could be off that much above or below WWV trying to callibrate that way.....

MontyS

Re: Display frequency calibration

The easiest and most reliable way for me to calibrate my K3 using WWV is to
switch between sidebands when a tone is being transmitted. When the two
tones are equal in pitch, the rig is calibrated.

Monty K2DLJ

Just another note: My K3 will not produce a audio tone below 200 cycles
in
the speaker.. ( could be my ears) so finding a zero beat is impossible as I
could be off that much above or below WWV trying to callibrate that way.....

--
View this message in context:
http://elecraft.365791.n2.nabble.com/Display-frequency-calibration-tp7563715p7563723.html
Sent from the Elecraft mailing list archive at Nabble.com.
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Nate Bargmann

Re: Display frequency calibration

In reply to this post by KD7PY

I have used Fldigi and its WWV analysis mode to do the same thing by
off-tuning the WWV carrier by 1 kHz. Of course, that presumes that the
sound card is accurately calibrated.

73, de Nate, N0NB >>

--

"The optimist proclaims that we live in the best of all
possible worlds. The pessimist fears this is true."

Ham radio, Linux, bikes, and more: http://www.n0nb.us
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Don Wilhelm-4

Re: Display frequency calibration

In reply to this post by KD7PY

Zero-beat is *not* zero frequency, so zero beat can be heard even when
the audio response drops off in the lower range.

When there are two tones closely spaced in frequency, they will produce
a third tone which is teh difference frequency between the tones. That
third tone will modulate the amplitude of the other two tones - sort of
a wow-wow-wow type sound. It is not unique to radio, it happens with
musical instruments too. Those who have tuned a stringed instrument
should be familiar with zero beat.

Zero beat is the point where the wow-wow-wow sound is as slow as you can
get it.

73,
Don W3FPR
On 10/5/2012 12:46 AM, K7WIA wrote:
> Just another note: My K3 will not produce a audio tone below 200 cycles in
> the speaker.. ( could be my ears) so finding a zero beat is impossible as I
> could be off that much above or below WWV trying to callibrate that way.....
>
>

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Jack Berry

Re: Display frequency calibration

Thanks to everyone who responded! I'm glad I asked the question, I don't remember seeing this topic covered in the last year, may be wrong, but I sure learned some great techniques.

Got it all working, checking one technique against the other including using CW/CW reverse and Auto spot as in the manual.

God Bless & Best 73!
Jack - WE5ST

________________________________
From: Don Wilhelm <[hidden email]>
To: K7WIA <[hidden email]>
Cc: [hidden email]
Sent: Friday, October 5, 2012 7:00 AM
Subject: Re: [Elecraft] Display frequency calibration

Zero-beat is *not* zero frequency, so zero beat can be heard even when
the audio response drops off in the lower range.

When there are two tones closely spaced in frequency, they will produce
a third tone which is teh difference frequency between the tones. That
third tone will modulate the amplitude of the other two tones - sort of
a wow-wow-wow type sound. It is not unique to radio, it happens with
musical instruments too. Those who have tuned a stringed instrument
should be familiar with zero beat.

Zero beat is the point where the wow-wow-wow sound is as slow as you can
get it.

73,
Don W3FPR
On 10/5/2012 12:46 AM, K7WIA wrote:
> Just another note: My K3 will not produce a audio tone below 200 cycles in
> the speaker.. ( could be my ears) so finding a zero beat is impossible as I
> could be off that much above or below WWV trying to callibrate that way.....
>
>

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Eric Swartz - WA6HHQ

Re: Display frequency calibration

Administrator

In reply to this post by KD7PY

Is your RX EQ set to roll off lower freqs? The 1-5 Hz zero beat note is easily heard when listening to the WWV carrier beating against the CW spot tone on the K3.

Eric

www.elecraft.com
_..._

On Oct 4, 2012, at 9:46 PM, K7WIA <[hidden email]> wrote:

> Just another note: My K3 will not produce a audio tone below 200 cycles in
> the speaker.. ( could be my ears) so finding a zero beat is impossible as I
> could be off that much above or below WWV trying to callibrate that way.....
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/Display-frequency-calibration-tp7563715p7563723.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
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Jack Berry

Re: Display frequency calibration

No, I'm set flat in rx eq. Was easy to zero beat using 20mHz WWV and the procedure.

Thanks!

On Oct 5, 2012, at 10:44 AM, Eric Swartz WA6HHQ - Elecraft <[hidden email]> wrote:

> Is your RX EQ set to roll off lower freqs? The 1-5 Hz zero beat note is easily heard when listening to the WWV carrier beating against the CW spot tone on the K3.
>
> Eric
>
> www.elecraft.com
> _..._
>
>
>
> On Oct 4, 2012, at 9:46 PM, K7WIA <[hidden email]> wrote:
>
>> Just another note: My K3 will not produce a audio tone below 200 cycles in
>> the speaker.. ( could be my ears) so finding a zero beat is impossible as I
>> could be off that much above or below WWV trying to callibrate that way.....
>>
>>
>>
>> --
>> View this message in context: http://elecraft.365791.n2.nabble.com/Display-frequency-calibration-tp7563715p7563723.html
>> Sent from the Elecraft mailing list archive at Nabble.com.
>> ______________________________________________________________
>> 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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