KREF3 External Reference card

[Trevor Smithers]

Just wondering if anyone from Elecraft might comment as to when the KREF3 external
reference input card may become available.

Trevor  G0KTN
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[Trevor Smithers]

Is the KREF3

(a) likely to be released in 2010
(b) under active development
(c) on the schedule for development
(d) on the back burner
(e) still thinking about it

73 to all
Trevor  G0KTN

-------- Original Message --------

Just wondering if anyone from Elecraft might comment as to when the KREF3 external
reference input card may become available.

Trevor  G0KTN


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[David Pratt]

I am afraid that I think you will find that it's on the back burner,
Trevor, but I hope Wayne will reply and then we shall all know once and
for all.  I have been pushing for this for a long time as it would be
nice to be able to feed my 10MHz Rubidium standard into J3 to get near
precise calibration.

I suspect that the problem is due to the internal reference oscillator
of all our K3s being different. Although the KREF3 schematic shows the
oscillator to be on 49.380 MHz, we all adjust this during the K3
calibration procedure. (Mine is on 49.379744)

I could be wrong, but I shall await Wayne's response.

73 de David G4DMP

In a recent message, Trevor Smithers <[hidden email]> writes
>
>Is the KREF3
>
>(a) likely to be released in 2010
>(b) under active development
>(c) on the schedule for development
>(d) on the back burner
>(e) still thinking about it
--
David G4DMP
Leeds, England, UK



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[Dave-3]

This question is one I have been asking annually at the Elecraft booth at
Hamcom in Dallas for the last 2 years. I will be asking again on Friday. The
last information given was in jun 2008 when I was told "availability in Jan
2009", heard no dates since! Based on this I didnt order the high spec
reference for either of my K3.

Dave

ww2r

Message: 40
Date: Wed, 9 Jun 2010 16:51:53 +0100
From: David Pratt <[hidden email]>
Subject: Re: [Elecraft] KREF3  External Reference card
To: Elecraft Reflector <[hidden email]>
Message-ID: <[hidden email]>
Content-Type: text/plain;charset=us-ascii;format=flowed

I am afraid that I think you will find that it's on the back burner,
Trevor, but I hope Wayne will reply and then we shall all know once and
for all.  I have been pushing for this for a long time as it would be
nice to be able to feed my 10MHz Rubidium standard into J3 to get near
precise calibration.

I suspect that the problem is due to the internal reference oscillator
of all our K3s being different. Although the KREF3 schematic shows the
oscillator to be on 49.380 MHz, we all adjust this during the K3
calibration procedure. (Mine is on 49.379744)

I could be wrong, but I shall await Wayne's response.

73 de David G4DMP

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[Eric Swartz - WA6HHQ]

The KREF3 is not in current planned development. I thought we had
removed the references to it in all of our docs. Is it still showing up
somewhere?

73, Eric
---

On 6/9/2010 9:49 AM, [hidden email] wrote:

> This question is one I have been asking annually at the Elecraft booth at
> Hamcom in Dallas for the last 2 years. I will be asking again on Friday. The
> last information given was in jun 2008 when I was told "availability in Jan
> 2009", heard no dates since! Based on this I didnt order the high spec
> reference for either of my K3.
>
> Dave
>
> ww2r
>
> Message: 40
> Date: Wed, 9 Jun 2010 16:51:53 +0100
> From: David Pratt<[hidden email]>
> Subject: Re: [Elecraft] KREF3  External Reference card
> To: Elecraft Reflector<[hidden email]>
> Message-ID:<[hidden email]>
> Content-Type: text/plain;charset=us-ascii;format=flowed
>
> I am afraid that I think you will find that it's on the back burner,
> Trevor, but I hope Wayne will reply and then we shall all know once and
> for all.  I have been pushing for this for a long time as it would be
> nice to be able to feed my 10MHz Rubidium standard into J3 to get near
> precise calibration.
>
> I suspect that the problem is due to the internal reference oscillator
> of all our K3s being different. Although the KREF3 schematic shows the
> oscillator to be on 49.380 MHz, we all adjust this during the K3
> calibration procedure. (Mine is on 49.379744)
>
> I could be wrong, but I shall await Wayne's response.
>
> 73 de David G4DMP
>
>    

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[N5GE]

On Wed, 09 Jun 2010 10:29:52 -0700, "Eric Swartz - WA6HHQ, Elecraft"
<[hidden email]> wrote:

Yes, the most obvious place is the label on the back panel and the
plug in the hole below it (#806 & #1055 here).

Do you intend to use the hole for something else?

>The KREF3 is not in current planned development. I thought we had
>removed the references to it in all of our docs. Is it still showing up
>somewhere?
>
>73, Eric
>---
[snip]

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[Julian, G4ILO]

Radio Amateur N5GE wrote

On Wed, 09 Jun 2010 10:29:52 -0700, "Eric Swartz - WA6HHQ, Elecraft"
<[e-mail]> wrote:

Yes, the most obvious place is the label on the back panel and the
plug in the hole below it (#806 & #1055 here).

Do you intend to use the hole for something else?

It is also mentioned in the copies of the docs I actually have, not to mention the specification that was given out when I actually purchased the radio.

It is disappointing that this feature is not going to be available. As someone who often uses WSPR and other digital modes where you work on an exact frequency, I was looking forward to having this capability.

[juergen piezo]

Hi Julian

This is disappointing news. I certainly would have not bought the TCXO's for my K3's if this fact was  known.

John

--- On Thu, 6/10/10, Julian, G4ILO <[hidden email]> wrote:

> From: Julian, G4ILO <[hidden email]>
> Subject: Re: [Elecraft] KREF3  External Reference card
> To: [hidden email]
> Date: Thursday, June 10, 2010, 12:55 AM
>
>
> Radio Amateur N5GE wrote:
> >
> > On Wed, 09 Jun 2010 10:29:52 -0700, "Eric Swartz -
> WA6HHQ, Elecraft"
> > <[hidden email]>
> wrote:
> >
> > Yes, the most obvious place is the label on the back
> panel and the
> > plug in the hole below it (#806 & #1055 here).
> >
> > Do you intend to use the hole for something else?
> >
> >
> It is also mentioned in the copies of the docs I actually
> have, not to
> mention the specification that was given out when I
> actually purchased the
> radio.
>
> It is disappointing that this feature is not going to be
> available. As
> someone who often uses WSPR and other digital modes where
> you work on an
> exact frequency, I was looking forward to having this
> capability.
>
> -----
> Julian, G4ILO. K2 #392  K3 #222.
> * G4ILO's Shack - http://www.g4ilo.com
> * KComm - http://www.g4ilo.com/kcomm.html
> * KTune - http://www.g4ilo.com/ktune.html
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/KREF3-External-Reference-card-tp5143036p5162030.html
> Sent from the [K3] mailing list archive at Nabble.com.
> ______________________________________________________________
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>

     
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[Jan Holmer SM6TUW]

Hi
Someone pointed out that we all have different 49 MHz oscillators. I guess
that many K3 owners have TCXO and thus no input for the voltage control
i.e. VCXO. This pin is indicated in the KREF3 shematic as pin 1  (VCTRL) of
Z1.
My KTCXO3-1 did not have this pin and could not be used vith the reference
PLL so I had to replace it with a VCXO.
*The design of the PLL is fairly simple and can be built on a small board
plugging directly into J4.
*One has to consider the resulting phase noise and spurs of the locked
KREF3.
*The Kref 3 must also fall back into a default mode when the extref is
removed or if the PLL unlocks.

I wonder if the promised optional board foor the K144XV allowing lock of the
116/118 MHz XO to the KREF3 is also cancelled ?
In that case we need the K144XV shematic.......

Jan
--
View this message in context: http://elecraft.365791.n2.nabble.com/KREF3-External-Reference-card-tp5143036p5163097.html
Sent from the [K3] mailing list archive at Nabble.com.
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[Jan Holmer SM6TUW]

Hi
 
Someone pointed out that we all have different 49 MHz oscillators. I guess that many K3 owners have oscillators without input for the voltage control.
This pin is indicated in the KREF3 shematic as pin 1  (VCTRL) of Z1.
My KTCXO3-1 is manufactured by KS Electronics (part number 1099) and pin 1 (VCTRL) is not
connected internally. It can not be used in a PLL. I had to replace mine with a VCXO.
I guess that is why Elecraft has cancelled that project, they would have to swap oscillators.

*The design of the PLL is fairly simple and can be built on a small board plugging directly into J4.
*One has to consider the resulting phase noise and spurs of the locked KREF3.
*The Kref 3 must also fall back into a default mode when the extref is disconnected (portable use) or if the PLL unlocks.

I wonder if the promised optional board foor the K144XV allowing lock of the 116/118 MHz XO to the KREF3 is also cancelled ?


Jan

[wayne burdick]

There appears to be more demand for this than we thought, so we're  
looking into it again.

Note that our planned external reference implementation would not  
require an exact 49.380000-MHz reference oscillator signal. It also  
doesn't require a pin-1 control voltage input on the TCXO module  
itself, as suggested earlier. It should work with any existing K3  
TCXO, either +/- 5 or +/- 1 PPM.

If you're interested, here are the details:

A new REF-lock module would be designed that plugs into the small 8-
pin connector near the top of the KREF3 PCB. The user's 10-MHz  
reference signal would be routed from the rear panel to the TMP  
connector on the KRE3 (this connector faces forward, into the DSP/
front panel area).

A microcontroller on the REF-lock module would be clocked by the 10-
MHz reference. If the signal were present, the microcontroller would  
continuously measure (and average) the frequency of the 49.38 MHz  
oscillator, obtaining a value to the nearest 1 Hz. Hysteresis would be  
applied to prevent "hunting," so the actual accuracy spec would  
probably be +/- 2 Hz. This translates to about +/- 1 Hz in operating  
frequency on 20 m.

Approximately once per second, the module would report the actual  
reference frequency to the K3's main MCU via a slow digital data line  
(labeled "100HZ" on the RF and KREF3 schematics). The main MCU would  
use this to calibrate the REF CAL value normally entered by the user.  
There would be no noticeable impact on performance.

If the 10 MHz external signal were not present, the user's normal REF  
CAL value would be used.

Let me know if you have thoughts on this implementation.

73,
Wayne
N6KR

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[Eugene Balinski]

10 MHz is an industry standard.  This is goof.  However,
you might want to consider a 1PPS GPS-trained input as
well.  

73,
Gene K1NR  

On Mon, 14 Jun 2010 16:15:39 -0700
 Wayne Burdick <[hidden email]> wrote:

> There appears to be more demand for this than we thought,
> so we're  
> looking into it again.
>
> Note that our planned external reference implementation
> would not  
> require an exact 49.380000-MHz reference oscillator
> signal. It also  
> doesn't require a pin-1 control voltage input on the TCXO
> module  
> itself, as suggested earlier. It should work with any
> existing K3  
> TCXO, either +/- 5 or +/- 1 PPM.
>
> If you're interested, here are the details:
>
> A new REF-lock module would be designed that plugs into
> the small 8-
> pin connector near the top of the KREF3 PCB. The user's
> 10-MHz  
> reference signal would be routed from the rear panel to
> the TMP  
> connector on the KRE3 (this connector faces forward, into
> the DSP/
> front panel area).
>
> A microcontroller on the REF-lock module would be clocked
> by the 10-
> MHz reference. If the signal were present, the
> microcontroller would  
> continuously measure (and average) the frequency of the
> 49.38 MHz  
> oscillator, obtaining a value to the nearest 1 Hz.
> Hysteresis would be  
> applied to prevent "hunting," so the actual accuracy spec
> would  
> probably be +/- 2 Hz. This translates to about +/- 1 Hz
> in operating  
> frequency on 20 m.
>
> Approximately once per second, the module would report
> the actual  
> reference frequency to the K3's main MCU via a slow
> digital data line  
> (labeled "100HZ" on the RF and KREF3 schematics). The
> main MCU would  
> use this to calibrate the REF CAL value normally entered
> by the user.  
> There would be no noticeable impact on performance.
>
> If the 10 MHz external signal were not present, the
> user's normal REF  
> CAL value would be used.
>
> Let me know if you have thoughts on this implementation.
>
> 73,
> Wayne
> N6KR
>
>

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[Eugene Balinski]

I should not type when tired.  That should have read "this
is good", not goof....   sorry about that..

73
K1NR

On Mon, 14 Jun 2010 22:04:31 -0400
 "Eugene Balinski" <[hidden email]> wrote:

> 10 MHz is an industry standard.  This is goof.  However,
> you might want to consider a 1PPS GPS-trained input as
> well.  
>
> 73,
> Gene K1NR  
>
> On Mon, 14 Jun 2010 16:15:39 -0700
>  Wayne Burdick <[hidden email]> wrote:
> > There appears to be more demand for this than we
> thought,
> > so we're  
> > looking into it again.
> >
> > Note that our planned external reference implementation
> > would not  
> > require an exact 49.380000-MHz reference oscillator
> > signal. It also  
> > doesn't require a pin-1 control voltage input on the
> TCXO
> > module  
> > itself, as suggested earlier. It should work with any
> > existing K3  
> > TCXO, either +/- 5 or +/- 1 PPM.
> >
> > If you're interested, here are the details:
> >
> > A new REF-lock module would be designed that plugs into
> > the small 8-
> > pin connector near the top of the KREF3 PCB. The user's
> > 10-MHz  
> > reference signal would be routed from the rear panel to
> > the TMP  
> > connector on the KRE3 (this connector faces forward,
> into
> > the DSP/
> > front panel area).
> >
> > A microcontroller on the REF-lock module would be
> clocked
> > by the 10-
> > MHz reference. If the signal were present, the
> > microcontroller would  
> > continuously measure (and average) the frequency of the
> > 49.38 MHz  
> > oscillator, obtaining a value to the nearest 1 Hz.
> > Hysteresis would be  
> > applied to prevent "hunting," so the actual accuracy
> spec
> > would  
> > probably be +/- 2 Hz. This translates to about +/- 1 Hz
> > in operating  
> > frequency on 20 m.
> >
> > Approximately once per second, the module would report
> > the actual  
> > reference frequency to the K3's main MCU via a slow
> > digital data line  
> > (labeled "100HZ" on the RF and KREF3 schematics). The
> > main MCU would  
> > use this to calibrate the REF CAL value normally
> entered
> > by the user.  
> > There would be no noticeable impact on performance.
> >
> > If the 10 MHz external signal were not present, the
> > user's normal REF  
> > CAL value would be used.
> >
> > Let me know if you have thoughts on this
> implementation.
> >
> > 73,
> > Wayne
> > N6KR
> >
> >
>

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> > http://www.qsl.net/donate.html
>
>

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[Trevor Smithers]

>There appears to be more demand for this than we thought, so we're  
>looking into it again.

This is excellent news and I'm sure will be much appreciated, especially with the number of
surplus Thunderbolt GPS and Rubidium 10MHz standards available at the moment.
 
I have no idea of the amount of R&D involved in producing this module but at which point in the
development cycle would you expect to be by the end of this year 2010 ?

73
Trevor  G0KTN
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[Trevor Smithers]

The recent announcement about development of an external reference option for the K3 is most
welcome and will allow users to obtain the best calibration possible especially for digi modes like
WSPR where 1Hz accuracy is required.

For anyone not quite sure about what it is, how to use it, or where to obtain the 10MHz external
high stability signal here are a few links to get started. The two most popular 10MHz oscillators
appear to be either GPS based (Trimble Thunderbolt) and Rubidium based (LPRO-101) both
are easily obtained on Ebay.

Set up and use the LPRO-101 units

http://kc.flex-radio.com/KnowledgebaseArticle50460.aspx

http://k9zw.wordpress.com/category/k9zw-built/

http://www.mentby.com/brian-lloyd/getting-a-rubidium-rb-reference.html

http://www.ka7oei.com/10meg_rubidium1.html

Setup and use of the Trimble Thunderbolt

http://www.vk4adc.com/gpsdo.php

http://www.prc68.com/I/ThunderBolt.shtml

http://trl.trimble.com/docushare/dsweb/Get/Document-10001/ThunderBoltBook2003.pdf

http://www.leapsecond.com/tbolt-faq.htm

http://www.leapsecond.com/pages/tapr-tbolt/

If you want to distribute the 10MHz signal to a number of instruments at the same time the TAPR
TADD-1 kit might be of interest.
http://www.tapr.org/kits_tadd-1.html

73 Trevor  G0KTN


 
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[Trevor Smithers]

Any news on the External Reference Option ?

73
Trevor  G0KTN

-------- Original Message  from Wayne N6KR dated 14 June 2010 --------

There appears to be more demand for this than we thought, so we're  
looking into it again.

Note that our planned external reference implementation would not  
require an exact 49.380000-MHz reference oscillator signal. It also  
doesn't require a pin-1 control voltage input on the TCXO module  
itself, as suggested earlier. It should work with any existing K3  
TCXO, either +/- 5 or +/- 1 PPM.

If you're interested, here are the details:

A new REF-lock module would be designed that plugs into the small 8-
pin connector near the top of the KREF3 PCB. The user's 10-MHz  
reference signal would be routed from the rear panel to the TMP  
connector on the KRE3 (this connector faces forward, into the DSP/
front panel area).

A microcontroller on the REF-lock module would be clocked by the 10-
MHz reference. If the signal were present, the microcontroller would  
continuously measure (and average) the frequency of the 49.38 MHz  
oscillator, obtaining a value to the nearest 1 Hz. Hysteresis would be  
applied to prevent "hunting," so the actual accuracy spec would  
probably be +/- 2 Hz. This translates to about +/- 1 Hz in operating  
frequency on 20 m.

Approximately once per second, the module would report the actual  
reference frequency to the K3's main MCU via a slow digital data line  
(labeled "100HZ" on the RF and KREF3 schematics). The main MCU would  
use this to calibrate the REF CAL value normally entered by the user.  
There would be no noticeable impact on performance.

If the 10 MHz external signal were not present, the user's normal REF  
CAL value would be used.

Let me know if you have thoughts on this implementation.

73,
Wayne
N6KR
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[wayne burdick]

Prototypes are working perfectly. We're getting ready for field testing.

Wayne
N6KR

----
http://www.elecraft.com

On Dec 22, 2010, at 4:41 PM, [hidden email] (Trevor Smithers) wrote:

> Any news on the External Reference Option ?
>
> 73
> Trevor  G0KTN
>
> -------- Original Message  from Wayne N6KR dated 14 June 2010 --------
>
> There appears to be more demand for this than we thought, so we're  
> looking into it again.
>
> Note that our planned external reference implementation would not  
> require an exact 49.380000-MHz reference oscillator signal. It also  
> doesn't require a pin-1 control voltage input on the TCXO module  
> itself, as suggested earlier. It should work with any existing K3  
> TCXO, either +/- 5 or +/- 1 PPM.
>
> If you're interested, here are the details:
>
> A new REF-lock module would be designed that plugs into the small 8-
> pin connector near the top of the KREF3 PCB. The user's 10-MHz  
> reference signal would be routed from the rear panel to the TMP  
> connector on the KRE3 (this connector faces forward, into the DSP/
> front panel area).
>
> A microcontroller on the REF-lock module would be clocked by the 10-
> MHz reference. If the signal were present, the microcontroller would  
> continuously measure (and average) the frequency of the 49.38 MHz  
> oscillator, obtaining a value to the nearest 1 Hz. Hysteresis would be  
> applied to prevent "hunting," so the actual accuracy spec would  
> probably be +/- 2 Hz. This translates to about +/- 1 Hz in operating  
> frequency on 20 m.
>
> Approximately once per second, the module would report the actual  
> reference frequency to the K3's main MCU via a slow digital data line  
> (labeled "100HZ" on the RF and KREF3 schematics). The main MCU would  
> use this to calibrate the REF CAL value normally entered by the user.  
> There would be no noticeable impact on performance.
>
> If the 10 MHz external signal were not present, the user's normal REF  
> CAL value would be used.
>
> Let me know if you have thoughts on this implementation.
>
> 73,
> Wayne
> N6KR
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[AD6XY]

Great news, I have been waiting for this option ever since my K3 arrived.

The method implies the phase noise of the 10MHz reference is not so important - which is useful to know.

My high spec reference is 5MHz and my cheap one 10MHz. The 10MHz will have worse phase noise than the TCXO in the K3 - though at the low frequencies it is not such an issue as it is at VHF and above. The 5MHz one is good - but it takes a long long time to lock. With the count method, it should not matter.

Mike

[Eugene Balinski]

All,

   Any chance of an external reference input for the K2?

73
K1NR
k2 6xxx
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[k.igor]

Perhaps there can be option to tell the MCU what frequency reference is used
to accommodate users with 5MHz or 1MHz references, not only 10MHz. I assume
there will be possibility to calibrate the internal oscillator to the good
reference and then disconnect the reference till next time (say once a year
or so). I hope there is no need to have the reference connected forever,
right?

73
Igor N1YX

-------- Original Message  from Wayne N6KR dated 14 June 2010 --------

There appears to be more demand for this than we thought, so we're  
looking into it again.

Note that our planned external reference implementation would not  
require an exact 49.380000-MHz reference oscillator signal. It also  
doesn't require a pin-1 control voltage input on the TCXO module  
itself, as suggested earlier. It should work with any existing K3  
TCXO, either +/- 5 or +/- 1 PPM.

If you're interested, here are the details:

A new REF-lock module would be designed that plugs into the small 8-
pin connector near the top of the KREF3 PCB. The user's 10-MHz  
reference signal would be routed from the rear panel to the TMP  
connector on the KRE3 (this connector faces forward, into the DSP/
front panel area).

A microcontroller on the REF-lock module would be clocked by the 10-
MHz reference. If the signal were present, the microcontroller would  
continuously measure (and average) the frequency of the 49.38 MHz  
oscillator, obtaining a value to the nearest 1 Hz. Hysteresis would be  
applied to prevent "hunting," so the actual accuracy spec would  
probably be +/- 2 Hz. This translates to about +/- 1 Hz in operating  
frequency on 20 m.

Approximately once per second, the module would report the actual  
reference frequency to the K3's main MCU via a slow digital data line  
(labeled "100HZ" on the RF and KREF3 schematics). The main MCU would  
use this to calibrate the REF CAL value normally entered by the user.  
There would be no noticeable impact on performance.

If the 10 MHz external signal were not present, the user's normal REF  
CAL value would be used.

Let me know if you have thoughts on this implementation.

73,
Wayne
N6KR
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