TCXO - 0.5PPM

[radioshoppe]

Hi Folks,

Been kicking around putting the 0.5PPM TCXO in my K3.  After doing some reading a question or two arises.  The instructions sheet(s) for the TCXO mentions using method 1,2 or 3 in the K3 manual to set frequency.  The K3 manual does not have a method 3 as I can find.  I've checked the reflector archive and found there is a data input feature in the K3 utility for inputting data received with the TCXO.  I think this equals method 3.  Someone make a note to change instructions/manuals if needed.

My question is do I need to do a method 1 or 2 before doing the data input?  Method 1 is to use a freq counter.  My freq counter is only about +/- 10 Htz depending on variables.  Method 2 is zero beat.  By ear the best I can get is about +/- 25 Htz.  How close do I need to get with method 1 or 2 (if needed) before inputting the data?

Second question, will the 0.5PPM TCXO eliminate the hysteresis I see during RTTY?  Depending on whether I tune to a signal from low to high or high to low I can see 10+ Htz difference in the signals frequency.  Or, are other factors at work?

Constructive thoughts appreciated.  

Happy New Year.  73

Jim, W0EM


     
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[wayne burdick]

At present, "method 3" remains unimplemented. Fortunately the TCXO's  
uncorrected drift is already less than +/- 0.5 PPM from 0 to 50 C.  
This was the target for "method 3".

73,
Wayne
N6KR

On Dec 28, 2010, at 10:18 AM, Jim Harris wrote:

> Hi Folks,
>
> Been kicking around putting the 0.5PPM TCXO in my K3.  After doing  
> some reading a question or two arises.  The instructions sheet(s)  
> for the TCXO mentions using method 1,2 or 3 in the K3 manual to set  
> frequency.  The K3 manual does not have a method 3 as I can find.  
> I've checked the reflector archive and found there is a data input  
> feature in the K3 utility for inputting data received with the  
> TCXO.  I think this equals method 3.  Someone make a note to change  
> instructions/manuals if needed.
>
> My question is do I need to do a method 1 or 2 before doing the data  
> input?  Method 1 is to use a freq counter.  My freq counter is only  
> about +/- 10 Htz depending on variables.  Method 2 is zero beat.  By  
> ear the best I can get is about +/- 25 Htz.  How close do I need to  
> get with method 1 or 2 (if needed) before inputting the data?
>
> Second question, will the 0.5PPM TCXO eliminate the hysteresis I see  
> during RTTY?  Depending on whether I tune to a signal from low to  
> high or high to low I can see 10+ Htz difference in the signals  
> frequency.  Or, are other factors at work?
>
> Constructive thoughts appreciated.
>
> Happy New Year.  73
>
> Jim, W0EM
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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[Steven.Zabarnick]

Wayne, is the TCXO drift spec for the period after warmup, or does it include the warmup period?

Steve N9SZ

>At present, "method 3" remains unimplemented. Fortunately the TCXO's  
>uncorrected drift is already less than +/- 0.5 PPM from 0 to 50 C.  
>This was the target for "method 3".

>73,
>Wayne
>N6KR


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[wayne burdick]

This is not specified, but to be safe, I'll say "after." However, I've  
observed very little additional drift during warmup. This is a TCXO,  
not an ovenized oscillator, so it would tend to correct for all  
temperature changes whether due to internally generated heat or  
ambient changes.

73,
Wayne
N6KR


On Dec 28, 2010, at 10:49 AM, [hidden email] wrote:

> Wayne, is the TCXO drift spec for the period after warmup, or does  
> it include the warmup period?
>
> Steve N9SZ
>
>> At present, "method 3" remains unimplemented. Fortunately the TCXO's
>> uncorrected drift is already less than +/- 0.5 PPM from 0 to 50 C.
>> This was the target for "method 3".
>
>> 73,
>> Wayne
>> N6KR
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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[ab2tc]

Hi,

Using method 2 you should easily be able to get it within a couple of Hz by beating it against the CW spotting tone. The instructions in the manual are quite detailed (make sure you scroll over to the bulleted list). The wow-wow-wow warble you hear near zero beat is very easy to recognize provided you have the audio levels of the carrier tone and the spotting tone reasonably well equalized. If you use WWV make sure you zero beat it against the carrier and not one of the many tones they play. To be sure, listen through the full minute cycle; the carrier never disappears; the tones will. I check mine regularly - currently I am off by 2.5-3Hz on 20MHz - not enough for me to worry about (I just have the standard reference osc).

AB2TC - Knut

jim.w0em wrote

Hi Folks,

Been kicking around putting the 0.5PPM TCXO in my K3.  After doing some reading a question or two arises.  The instructions sheet(s) for the TCXO mentions using method 1,2 or 3 in the K3 manual to set frequency.  The K3 manual does not have a method 3 as I can find.  I've checked the reflector archive and found there is a data input feature in the K3 utility for inputting data received with the TCXO.  I think this equals method 3.  Someone make a note to change instructions/manuals if needed.

My question is do I need to do a method 1 or 2 before doing the data input?  Method 1 is to use a freq counter.  My freq counter is only about +/- 10 Htz depending on variables.  Method 2 is zero beat.  By ear the best I can get is about +/- 25 Htz.  How close do I need to get with method 1 or 2 (if needed) before inputting the data?

Second question, will the 0.5PPM TCXO eliminate the hysteresis I see during RTTY?  Depending on whether I tune to a signal from low to high or high to low I can see 10+ Htz difference in the signals frequency.  Or, are other factors at work?

Constructive thoughts appreciated.  

Happy New Year.  73

Jim, W0EM
<snip>

[radioshoppe]

Hi,

Thank you Wayne, for your fast response.  Seems I'm better off to stick with my stock TCXO as I've never had much luck with method 1 and 2.  My K3 was in the shop 3-4 months ago and looks like Rene set it's frequency dead on.

Happy New Year. 73

Jim, W0EM


--- On Tue, 12/28/10, Wayne Burdick <[hidden email]> wrote:

> From: Wayne Burdick <[hidden email]>
> Subject: Re: [Elecraft] TCXO - 0.5PPM
> To: "Jim Harris" <[hidden email]>
> Cc: "Elecraft Email" <[hidden email]>
> Date: Tuesday, December 28, 2010, 6:24 PM
> At present, "method 3" remains
> unimplemented. Fortunately the TCXO's uncorrected drift is
> already less than +/- 0.5 PPM from 0 to 50 C. This was the
> target for "method 3".
>
> 73,
> Wayne
> N6KR
>
> On Dec 28, 2010, at 10:18 AM, Jim Harris wrote:
>
> > Hi Folks,
> >
> > Been kicking around putting the 0.5PPM TCXO in my
> K3.  After doing some reading a question or two
> arises.  The instructions sheet(s) for the TCXO
> mentions using method 1,2 or 3 in the K3 manual to set
> frequency.  The K3 manual does not have a method 3 as I
> can find.  I've checked the reflector archive and found
> there is a data input feature in the K3 utility for
> inputting data received with the TCXO.  I think this
> equals method 3.  Someone make a note to change
> instructions/manuals if needed.
> >
> > My question is do I need to do a method 1 or 2 before
> doing the data input?  Method 1 is to use a freq
> counter.  My freq counter is only about +/- 10 Htz
> depending on variables.  Method 2 is zero beat. 
> By ear the best I can get is about +/- 25 Htz.  How
> close do I need to get with method 1 or 2 (if needed) before
> inputting the data?
> >
> > Second question, will the 0.5PPM TCXO eliminate the
> hysteresis I see during RTTY?  Depending on whether I
> tune to a signal from low to high or high to low I can see
> 10+ Htz difference in the signals frequency.  Or, are
> other factors at work?
> >
> > Constructive thoughts appreciated.
> >
> > Happy New Year.  73
> >
> > Jim, W0EM
> >
> >
> >
> >
> ______________________________________________________________
> > 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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[radioshoppe]

Knut,

Thank you for your suggestion.  As mentioned in my email about the best I can do with Method 2 is about +/20 hz.  I've tried it numerous times.  When adjusting the frequency I hear a dead spot 25-40+ hz wide that has no womp-womp-womp.  I take half of the width and set the frequency there.  Spend 20+ years around aircraft and very noisy missile sources in the Air Force 30-50 years ago.  I had rather buy more radios/accessories than pay $6-10,000 for a set of hearing aides.

Happy new year,  73

Jim, W0EM

ab2tc wrote

Hi,

Using method 2 you should easily be able to get it within a couple of Hz by beating it against the CW spotting tone. The instructions in the manual are quite detailed

AB2TC - Knut

jim.w0em wrote

Hi Folks,

Been kicking around putting the 0.5PPM TCXO in my K3.  

Happy New Year.  73

Jim, W0EM
<snip>

[Don Wilhelm-4]

  Jim,

Since you say you have hearing loss, that can prove difficult - I would
suggest a "visual aid".

You might try using Spectrogram (or another FFT audio spectrum analyzer)
when attempting Method 2.
You should see the spike from the sidetone and the spike from the WWV
carrier on the display,
Once you get close to the correct point, you might be better able to
hear the wow-wow-wow - adjust the AF gain to bring the ampliude of both
signals nearly the same, and you should hear it.

Go for the hearing aids too - they will make life more pleasant and
enjoyable.  I hear if you served in any branch of the US military for
more than 6 months, you can get them free through the VA - worth
checking out.  I will be investigating that when I need new ones.

73,
Don W3FPR

On 12/29/2010 1:12 PM, radioshoppe wrote:

> Knut,
>
> Thank you for your suggestion.  As mentioned in my email about the best I
> can do with Method 2 is about +/20 hz.  I've tried it numerous times.  When
> adjusting the frequency I hear a dead spot 25-40+ hz wide that has no
> womp-womp-womp.  I take half of the width and set the frequency there.
> Spend 20+ years around aircraft and very noisy missile sources in the Air
> Force 30-50 years ago.  I had rather buy more radios/accessories than pay
> $6-10,000 for a set of hearing aides.
>
> Happy new year,  73
>
> Jim, W0EM
>

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[Kok Chen]

On Dec 29, 2010, at 12/29    10:12 AM, radioshoppe wrote:

> As mentioned in my email about the best I can do with Method 2 is  
> about +/20 hz.

Do you have an RTTY program that has a crossed-ellipse display  
(affectionately called "crossed bananas" by RTTY nuts)?  If so, that  
might get you closer than 20 Hz by using your sight instead of your  
hearing.

A steady Mark tone should appear as a single oval that is perfectly  
vertical or perfectly horizontal.  You tune your rig by the amount of  
the mark tone that you have set -- if you can set the mark tone to  
some "nice" tone, like 2000 Hz instead of 2125 Hz, you won't have to  
do much mental gymnastics to figure out the proper VFO offset.

Not all software have a narrow cross ellipse display, so you may need  
to find one that is satisfactory.  Basically, with the standard RTTY  
shift, the cross-ellipse will go through 90 degrees of rotation with  
170 Hz worth of offset.

If you can find software which you can change the FSK shift, you can  
get even more accurate readouts.  For example, setting the shift  
(i.e., the difference between the Mark and Space tone) to 50 Hz will  
move the peak of the oval by 90 degrees with just a 50 Hz VFO offset.

I just tried WWV in cocoaModem's "wideband RTTY" display (whose oval  
is narrower than for other RTTY modes in cocoaModem).  By using an FSK  
Shift of 10 Hz, I can easily eyeball a 1 Hz change.

If your RTTY software does not allow such a narrow shift, it might  
have MSK (Minimal Shift Keyed) mode, where the shift is 22.5 Hz.  
(Note: MSK, not MFSK; they are different animals.)

If you are using WWV, be sure to use a narrow filter so the  
modulations don't come through, or wait for the sidetones and  
subcarriers to stop.  Else you will get an oval that shakes around :-).

Alternately, you can look for iPhone apps for tuning musical  
instruments.  Set your VFO offset for middle C or something :-).

73
Chen, W7AY



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[ab2tc]

Hello again,

While I don't disagree with other people's suggestions that visual aids would be of assistance I am still a little bit at a loss (no pun intended) why your hearing loss should be a serious obstacle to detecting the zero beat on the side tone. Do you have any problem hearing your chosen side tone at all? In CW mode turn the AF volume down to 0 and press "Spot" to hear the side tone. If you can't hear the side tone, you need to adjust its frequency and/or amplitude until you can hear it clearly (hold "Pitch" to adjust frequency, hold "Mon" to adjust volume). Now is the time to turn the AF gain back up until you can hear stuff roughly equally as loud as the side tone. The flutter or warble in the side tone generally can't be heard easily unless you are within 20Hz or so of the desired frequency, so maybe that's your problem. I can send you a recording of what WWV sounds like with say a 10, 3 and nominally 0 error if you think it might help. Tried this just now and the fast flutter at 20Hz frequency error is clearly audible.

AB2TC - Knut

radioshoppe wrote

Knut,

Thank you for your suggestion.  As mentioned in my email about the best I can do with Method 2 is about +/20 hz.  I've tried it numerous times.  When adjusting the frequency I hear a dead spot 25-40+ hz wide that has no womp-womp-womp.  I take half of the width and set the frequency there.  Spend 20+ years around aircraft and very noisy missile sources in the Air Force 30-50 years ago.  I had rather buy more radios/accessories than pay $6-10,000 for a set of hearing aides.

Happy new year,  73

Jim, W0EM
<snip>

[ab2tc]

Hello again again,

Here are links to 4 recordings made for method 2 with wwv at 10MHz with a tuning error of 0, 3, 10 and 20Hz (approximately). The sidetone and center frequency is 800Hz and the CW BW is 1100Hz.

http://ab2tc.getmyip.com:8000/pictures/wwv_error_0.mp3
http://ab2tc.getmyip.com:8000/pictures/wwv_error_3.mp3
http://ab2tc.getmyip.com:8000/pictures/wwv_error_10.mp3
http://ab2tc.getmyip.com:8000/pictures/wwv_error_20.mp3

AB2TC - Knut

[Julian, G4ILO]

Rather than try to listen for zero beat I offset the dial reading by 1kHz and use a computer sound card program to measure the frequency of the audio tone. Fldigi is a good program to use for this.