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[K3] K3EXREF K144REFLK and K144XV

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Tim Taylor

[K3] K3EXREF K144REFLK and K144XV

Hello,

I have a K3 with the K3EXREF, K144REFLK and K144XV.

Let me start by saying that the K3EXREF performs as described. It keeps the
K3 tuned to a frequency within about plus/minus 2 Hz. However, I don't think
it operates the way I thought. I initially thought that the K3EXREF adjusted
the actual 49 MHz reference frequency to stabilize it to an external
reference. After some testing, it appears that the 49 MHz reference
frequency from the oscillator is never changed by the K3EXREF. It appears
that the offset between the 49 MHz actual frequency and the 10 MHz reference
is compensated for in firmware. I have monitored the 49 MHz reference and it
continues to drift like it always has. At the same time, the tuned frequency
of the K3 stays within 2 Hz of the actual frequency.

The reason for the research was the continued inaccuracy of the K144XV
frequency after the installation of both the KEXREF and the K144REFLK. The
K144REFLK does lock the LO of the K144XV to the 49 MHz reference. It reduces
the "large" uncompensated drift of the K144XV down to between .5 and 1 PPM.
That is, it will drift in the neighborhood of 100 Hz AFTER warmup. This
appears to follow the spec of the 49 MHz reference oscillator. This DOES NOT
track the K3EXREF compensated stability. I would have expected the K144XV to
stay within about plus/minus 6 Hz when stabilized to the K3EXREF.

I called tech support and they seemed to confirm my analysis. The K3EXREF
only works from 160 to 6 meters. The firmware has not been written to have
it work with the K144XV.

So right now, the K3EXREF will stabilize the frequency of the basic radio;
however, it will not stabilize the frequency of the K144XV. It is my
understanding that the firmware for the K144XV is "in the que".

73,

Tim K8XS

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David Pratt

Re: [K3] K3EXREF K144REFLK and K144XV

Tim - My understanding is that the K3EXREF does not stabilise the
transverter offset. I believe this is planned in a future K3 firmware
upgrade, but as far as I am aware this has not yet happened.

73 de David G4DMP

In a recent message, Tim Taylor <[hidden email]> writes
>So right now, the K3EXREF will stabilize the frequency of the basic radio;
>however, it will not stabilize the frequency of the K144XV. It is my
>understanding that the firmware for the K144XV is "in the que".
--
+ - - - - - - - - - - - - - - - - +
| David M Pratt, Kippax, Leeds. |
| Website: http://www.g4dmp.co.uk |
+ - - - - - - - - - - - - - - - - +

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Tim Taylor

Re: [K3] K3EXREF K144REFLK and K144XV

That is my understanding.
73,
Tim

-----Original Message-----
From: David Pratt [mailto:[hidden email]]
Sent: Thursday, June 09, 2011 12:36 PM
To: Tim Taylor
Cc: [hidden email]
Subject: Re: [Elecraft] [K3] K3EXREF K144REFLK and K144XV

Tim - My understanding is that the K3EXREF does not stabilise the
transverter offset. I believe this is planned in a future K3 firmware
upgrade, but as far as I am aware this has not yet happened.

73 de David G4DMP

In a recent message, Tim Taylor <[hidden email]> writes
>So right now, the K3EXREF will stabilize the frequency of the basic radio;
>however, it will not stabilize the frequency of the K144XV. It is my
>understanding that the firmware for the K144XV is "in the que".
--
+ - - - - - - - - - - - - - - - - +
| David M Pratt, Kippax, Leeds. |
| Website: http://www.g4dmp.co.uk |
+ - - - - - - - - - - - - - - - - +

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wayne burdick

Re: [K3] K3EXREF K144REFLK and K144XV

Administrator

In reply to this post by David Pratt

I'm on the hook for this. I'll send out test code when it's ready.

73,
Wayne
N6KR

On Jun 9, 2011, at 9:36 AM, David Pratt wrote:

> Tim - My understanding is that the K3EXREF does not stabilise the
> transverter offset. I believe this is planned in a future K3 firmware
> upgrade, but as far as I am aware this has not yet happened.
>
> 73 de David G4DMP
>
> In a recent message, Tim Taylor <[hidden email]> writes
>> So right now, the K3EXREF will stabilize the frequency of the basic
>> radio;
>> however, it will not stabilize the frequency of the K144XV. It is my
>> understanding that the firmware for the K144XV is "in the que".
> --
> + - - - - - - - - - - - - - - - - +
> | David M Pratt, Kippax, Leeds. |
> | Website: http://www.g4dmp.co.uk |
> + - - - - - - - - - - - - - - - - +
>
>
>
> ______________________________________________________________
> 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

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Dave New, N8SBE

Re: [K3] K3EXREF K144REFLK and K144XV

In reply to this post by Tim Taylor

Wayne,

What I guess I don't understand is why the TXCO functionality was never
finished. Seems like that would help a number of accuracy/calibration
issues, and I bought the .5 ppm option expecting that it would be
useful.

I'm disappointed in what appears to be a decision to abandon finishing
that project.

On a related note, it wouldn't hurt to do something to fix the real time
clock, so I don't have to keep syncing it with my laptop to keep it
reasonably on time.

Thanks,

-- Dave, N8SBE

> -------- Original Message --------
> Subject: Re: [Elecraft] [K3] K3EXREF K144REFLK and K144XV
> From: Wayne Burdick <[hidden email]>
> Date: Thu, June 09, 2011 1:02 pm
> To: David Pratt <[hidden email]>
> Cc: [hidden email], Tim Taylor <[hidden email]>
>
>
> I'm on the hook for this. I'll send out test code when it's ready.
>
> 73,
> Wayne
> N6KR
>
> On Jun 9, 2011, at 9:36 AM, David Pratt wrote:
>
> > Tim - My understanding is that the K3EXREF does not stabilise the
> > transverter offset. I believe this is planned in a future K3 firmware
> > upgrade, but as far as I am aware this has not yet happened.
> >
> > 73 de David G4DMP
> >
> > In a recent message, Tim Taylor <[hidden email]> writes
> >> So right now, the K3EXREF will stabilize the frequency of the basic
> >> radio;
> >> however, it will not stabilize the frequency of the K144XV. It is my
> >> understanding that the firmware for the K144XV is "in the que".
> > --
> > + - - - - - - - - - - - - - - - - +
> > | David M Pratt, Kippax, Leeds. |
> > | Website: http://www.g4dmp.co.uk |
> > + - - - - - - - - - - - - - - - - +
> >
> >
> >
> > ______________________________________________________________
> > 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
>
> ______________________________________________________________
> 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

wayne burdick

Re: [K3] K3EXREF K144REFLK and K144XV

Administrator

Dave,

The 49 MHz "1-ppm" oscillator is a TXCO, and it works well (0.5 ppm
from 0 to 50 C). Originally we thought we would not be able to hit
this target without adding firmware-based correction.

I did implement the firmware correction, but I wasn't happy with it,
because it didn't provide much of an improvement beyond 0.5 ppm with
all oscillators tested. What I found is that I had to create data for
every 1 degree C, rather than every 5 degrees, in order to get to hit
a more aggressive 0.25 ppm target. But the manufacturer of the TCXO
had predicted that 5-degree data points would be sufficient for the
algorithm, and that is what they supply with the oscillators. We could
ask the for 1-degree data, but that would increase the cost (not to
mention create five times as much data). It would also not be of much
help to those who already had 1-ppm TCXOs installed.

What we could do in a future release is provide a way for customers to
manually generate and use 1-degree data. Call it "Method 4." It seems
a bit onerous, but here's the idea: First, you'd put your K3 in the
refrigerator long enough to get to 0C, or the desired low operating
temp. Next, set the rig up with an accurate frequency counter
connected to the output of the oscillator, and put the cover back on,
or at least part of the way on (the freq counter cable has to come out
at the back or side). Then, as the radio heats up, write down the
oscillator frequencies for each 1-degree point. When it gets as hot as
it's going to get due to ambient temperature, turn on a hot lamp or
hair dryer and aim it at the top cover, about where the oscillator is.
Continue heating and logging data until the desired max operating
temperature is reached.

You could then enter this info into a revised oscillator calibration
data screen in K3 Utility. I'd have to add the firmware necessary to
allow the oscillator to be updated continuously based on 1-degre data.

This is a long answer to your question. It begs the further question,
Would anyone bother?

73,
Wayne
N6KR

On Jun 9, 2011, at 10:36 AM, Dave New, N8SBE wrote:

> Wayne,
>
> What I guess I don't understand is why the TXCO functionality was
> never
> finished. Seems like that would help a number of accuracy/calibration
> issues, and I bought the .5 ppm option expecting that it would be
> useful.
>
> I'm disappointed in what appears to be a decision to abandon finishing
> that project.
>
> On a related note, it wouldn't hurt to do something to fix the real
> time
> clock, so I don't have to keep syncing it with my laptop to keep it
> reasonably on time.
>
> Thanks,
>
> -- Dave, N8SBE
>
>> -------- Original Message --------
>> Subject: Re: [Elecraft] [K3] K3EXREF K144REFLK and K144XV
>> From: Wayne Burdick <[hidden email]>
>> Date: Thu, June 09, 2011 1:02 pm
>> To: David Pratt <[hidden email]>
>> Cc: [hidden email], Tim Taylor <[hidden email]>
>>
>>
>> I'm on the hook for this. I'll send out test code when it's ready.
>>
>> 73,
>> Wayne
>> N6KR
>>
>> On Jun 9, 2011, at 9:36 AM, David Pratt wrote:
>>
>>> Tim - My understanding is that the K3EXREF does not stabilise the
>>> transverter offset. I believe this is planned in a future K3
>>> firmware
>>> upgrade, but as far as I am aware this has not yet happened.
>>>
>>> 73 de David G4DMP
>>>
>>> In a recent message, Tim Taylor <[hidden email]> writes
>>>> So right now, the K3EXREF will stabilize the frequency of the basic
>>>> radio;
>>>> however, it will not stabilize the frequency of the K144XV. It is
>>>> my
>>>> understanding that the firmware for the K144XV is "in the que".
>>> --
>>> + - - - - - - - - - - - - - - - - +
>>> | David M Pratt, Kippax, Leeds. |
>>> | Website: http://www.g4dmp.co.uk |
>>> + - - - - - - - - - - - - - - - - +
>>>
>>>
>>>
>>> ______________________________________________________________
>>> 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
>>
>> ______________________________________________________________
>> 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

Terry Posey

Re: [K3] K3EXREF K144REFLK and K144XV

I am not everyone, but I would NOT bother with an environmental chamber
test/calibration.

Terry K4RX

XXXXXXXXXXX
This is a long answer to your question. It begs the further question,
Would anyone bother?

73,
Wayne
N6KR

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wayne burdick

Re: [K3] K3EXREF K144REFLK and K144XV

Administrator

I suspect you're not the only one, and that's why I haven't been
pushing this.

Wayne
N6KR

On Jun 9, 2011, at 11:18 AM, Terry Posey wrote:

> I am not everyone, but I would NOT bother with an environmental
> chamber
> test/calibration.
>
> Terry K4RX
>
> XXXXXXXXXXX
> This is a long answer to your question. It begs the further question,
> Would anyone bother?
>
> 73,
> Wayne
> N6KR

Dave New, N8SBE

Re: [K3] K3EXREF K144REFLK and K144XV

In reply to this post by Tim Taylor

Wayne,

Thank you for your detailed answer.

I was following the conversation (or thought I was) that the external
reference and transverter lock was another way to get high
stability/accuracy at UHF and higher frequencies. I guess the issue
then becomes, which is more annoying and/or more effective?

Maybe I'm missing something obvious, but wouldn't a .25 (or better)
ppm-calibrated TXCO be less expensive than all the other stuff, and take
up a lot less room (and weight)?

I'm really curious about this (and the RTC question I posed) mainly
because I'm working with a supplier right now on a fix for a drifting
time-of-day clock issue, and the proposed solution involves a Seiko TXCO
oscillator that operates over -40C to +85C (automotive interior) and
supposedly gives .5 ppm.

73,

-- Dave, N8SBE

> -------- Original Message --------
> Subject: Re: [Elecraft] [K3] K3EXREF K144REFLK and K144XV
> From: Wayne Burdick <[hidden email]>
> Date: Thu, June 09, 2011 2:08 pm
> To: "Dave New, N8SBE" <[hidden email]>
> Cc: [hidden email], "Tim Taylor" <[hidden email]>,
> "David Pratt" <[hidden email]>
>
>
> Dave,
>
> The 49 MHz "1-ppm" oscillator is a TXCO, and it works well (0.5 ppm
> from 0 to 50 C). Originally we thought we would not be able to hit
> this target without adding firmware-based correction.
>
> I did implement the firmware correction, but I wasn't happy with it,
> because it didn't provide much of an improvement beyond 0.5 ppm with
> all oscillators tested. What I found is that I had to create data for
> every 1 degree C, rather than every 5 degrees, in order to get to hit
> a more aggressive 0.25 ppm target. But the manufacturer of the TCXO
> had predicted that 5-degree data points would be sufficient for the
> algorithm, and that is what they supply with the oscillators. We could
> ask the for 1-degree data, but that would increase the cost (not to
> mention create five times as much data). It would also not be of much
> help to those who already had 1-ppm TCXOs installed.
>
> What we could do in a future release is provide a way for customers to
> manually generate and use 1-degree data. Call it "Method 4." It seems
> a bit onerous, but here's the idea: First, you'd put your K3 in the
> refrigerator long enough to get to 0C, or the desired low operating
> temp. Next, set the rig up with an accurate frequency counter
> connected to the output of the oscillator, and put the cover back on,
> or at least part of the way on (the freq counter cable has to come out
> at the back or side). Then, as the radio heats up, write down the
> oscillator frequencies for each 1-degree point. When it gets as hot as
> it's going to get due to ambient temperature, turn on a hot lamp or
> hair dryer and aim it at the top cover, about where the oscillator is.
> Continue heating and logging data until the desired max operating
> temperature is reached.
>
> You could then enter this info into a revised oscillator calibration
> data screen in K3 Utility. I'd have to add the firmware necessary to
> allow the oscillator to be updated continuously based on 1-degre data.
>
> This is a long answer to your question. It begs the further question,
> Would anyone bother?
>
> 73,
> Wayne
> N6KR
>
>
> On Jun 9, 2011, at 10:36 AM, Dave New, N8SBE wrote:
>
> > Wayne,
> >
> > What I guess I don't understand is why the TXCO functionality was
> > never
> > finished. Seems like that would help a number of accuracy/calibration
> > issues, and I bought the .5 ppm option expecting that it would be
> > useful.
> >
> > I'm disappointed in what appears to be a decision to abandon finishing
> > that project.
> >
> > On a related note, it wouldn't hurt to do something to fix the real
> > time
> > clock, so I don't have to keep syncing it with my laptop to keep it
> > reasonably on time.
> >
> > Thanks,
> >
> > -- Dave, N8SBE
> >
> >> -------- Original Message --------
> >> Subject: Re: [Elecraft] [K3] K3EXREF K144REFLK and K144XV
> >> From: Wayne Burdick <[hidden email]>
> >> Date: Thu, June 09, 2011 1:02 pm
> >> To: David Pratt <[hidden email]>
> >> Cc: [hidden email], Tim Taylor <[hidden email]>
> >>
> >>
> >> I'm on the hook for this. I'll send out test code when it's ready.
> >>
> >> 73,
> >> Wayne
> >> N6KR
> >>
> >> On Jun 9, 2011, at 9:36 AM, David Pratt wrote:
> >>
> >>> Tim - My understanding is that the K3EXREF does not stabilise the
> >>> transverter offset. I believe this is planned in a future K3
> >>> firmware
> >>> upgrade, but as far as I am aware this has not yet happened.
> >>>
> >>> 73 de David G4DMP
> >>>
> >>> In a recent message, Tim Taylor <[hidden email]> writes
> >>>> So right now, the K3EXREF will stabilize the frequency of the basic
> >>>> radio;
> >>>> however, it will not stabilize the frequency of the K144XV. It is
> >>>> my
> >>>> understanding that the firmware for the K144XV is "in the que".
> >>> --
> >>> + - - - - - - - - - - - - - - - - +
> >>> | David M Pratt, Kippax, Leeds. |
> >>> | Website: http://www.g4dmp.co.uk |
> >>> + - - - - - - - - - - - - - - - - +
> >>>
> >>>
> >>>
> >>> ______________________________________________________________
> >>> 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
> >>
> >> ______________________________________________________________
> >> 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

Dave New, N8SBE

Re: [K3] K3EXREF K144REFLK and K144XV

In reply to this post by Tim Taylor

Sorry, Seiko is the RTC -- google for S35390A_E.pdf

Dallas (Maxim) is the TXCO supplier -- google for DS32kHz-DS32KHZS.pdf

73,

-- Dave, N8SBE

Bruce Beford-2

Re: [K3] K3EXREF K144REFLK and K144XV

In reply to this post by Tim Taylor

Couldn't this be automated for those with the K3EXREF?

Since the K3EXREF is applying a "fudge factor" (technical term) based on the
instantaneous error of the 49 MHz TXCO, one could "simply" read the
correction and the front panel temp over a thermal "run". The data could
then be massaged (another techinal term) internally, to come up with the
tabular data needed. Yes?

Bruce, N1RX

Wayne, N6KR wrote:

> What we could do in a future release is provide a way for customers to
> manually generate and use 1-degree data. Call it "Method 4." It seems
> a bit onerous, but here's the idea: First, you'd put your K3 in the
> refrigerator long enough to get to 0C, or the desired low operating
> temp. Next, set the rig up with an accurate frequency counter
> connected to the output of the oscillator, and put the cover back on,
> or at least part of the way on (the freq counter cable has to come out
> at the back or side). Then, as the radio heats up, write down the
> oscillator frequencies for each 1-degree point. <snip>

______________________________________________________________
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wayne burdick

Re: [K3] K3EXREF K144REFLK and K144XV

Administrator

There is no need to do any type of temperature correction if you're
using the K3EXREF. This option uses an external reference to send
corrections to the K3's MCU automatically so that it always knows the
actual frequency of the 49-MHz oscillator.

What some are asking for is that the K144XV's PLL module also receive
the benefit of this correction when the K3EXREF is installed. That's a
small matter of programming on my part.

73,
Wayne
N6KR

On Jun 9, 2011, at 1:23 PM, Bruce Beford wrote:

> Couldn't this be automated for those with the K3EXREF?
>
> Since the K3EXREF is applying a "fudge factor" (technical term)
> based on the
> instantaneous error of the 49 MHz TXCO, one could "simply" read the
> correction and the front panel temp over a thermal "run". The data
> could
> then be massaged (another techinal term) internally, to come up with
> the
> tabular data needed. Yes?
>
> Bruce, N1RX
>
>
>
>
>
> Wayne, N6KR wrote:
>
>> What we could do in a future release is provide a way for customers
>> to
>> manually generate and use 1-degree data. Call it "Method 4." It seems
>> a bit onerous, but here's the idea: First, you'd put your K3 in the
>> refrigerator long enough to get to 0C, or the desired low operating
>> temp. Next, set the rig up with an accurate frequency counter
>> connected to the output of the oscillator, and put the cover back on,
>> or at least part of the way on (the freq counter cable has to come
>> out
>> at the back or side). Then, as the radio heats up, write down the
>> oscillator frequencies for each 1-degree point. <snip>
>
>
> ______________________________________________________________
> 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

Bruce Beford-2

Re: [K3] K3EXREF K144REFLK and K144XV

In reply to this post by Tim Taylor

I understand that when using the K3EXREF there is no need for this data.
But, what I was wondering is if this would be a method by which an end user
of the KTCXO3-1, (or Elecraft internally) could use this or a similar method
to compile this 1 degree increment data easily? It could be used when not
running with the external ref online, or could be included as test data from
Elecraft with a KTCXO3-1 purchase.

I am also interested in the K144XV's PLL being corrected by the K3EXREF, and
hopefully, an automated correction instead of the 116MHz/118MHz manual
calculation and data entry now required when using the K144RFLCK.

73,
Bruce
N1RX

> There is no need to do any type of temperature correction if you're
> using the K3EXREF. This option uses an external reference to send
> corrections to the K3's MCU automatically so that it always knows the
> actual frequency of the 49-MHz oscillator.

> What some are asking for is that the K144XV's PLL module also receive
> the benefit of this correction when the K3EXREF is installed. That's a
> small matter of programming on my part.

> 73, Wayne N6KR

______________________________________________________________
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wayne burdick

Re: [K3] K3EXREF K144REFLK and K144XV

Administrator

On Jun 9, 2011, at 1:42 PM, Bruce Beford wrote:

> I understand that when using the K3EXREF there is no need for this
> data.
> But, what I was wondering is if this would be a method by which an
> end user
> of the KTCXO3-1, (or Elecraft internally) could use this or a
> similar method
> to compile this 1 degree increment data easily? It could be used
> when not
> running with the external ref online, or could be included as test
> data from
> Elecraft with a KTCXO3-1 purchase.

While this is possible, it may not be practical. We don't have
facilities for wide temperature cycling of the K3s (we do burn them
in, of course), and it would be expensive and labor-intensive to add
this. My contention is that 0.5 ppm with the high-precision oscillator
is sufficient for the vast majority of users, and most of those who
need a better TC could use the K3EXREF. This leaves a small number who
might be interested in tighter calibration data (1 degree units), and
I'm suggesting that the only way we can handle this at present is to
allow users to generate their own data.

>
> I am also interested in the K144XV's PLL being corrected by the
> K3EXREF, and
> hopefully, an automated correction instead of the 116MHz/118MHz manual
> calculation and data entry now required when using the K144RFLCK.

This I'm going to do for sure.

Wayne

>
> 73,
> Bruce
> N1RX
>
>
>
>> There is no need to do any type of temperature correction if you're
>> using the K3EXREF. This option uses an external reference to send
>> corrections to the K3's MCU automatically so that it always knows the
>> actual frequency of the 49-MHz oscillator.
>
>> What some are asking for is that the K144XV's PLL module also receive
>> the benefit of this correction when the K3EXREF is installed.
>> That's a
>> small matter of programming on my part.
>
>> 73, Wayne N6KR
>
>
>
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Vernon Mauery

Re: [K3] K3EXREF K144REFLK and K144XV

It sounds like someone with lots of spare time on their hands and some
fancy calibration equipment could make some money by having people
send them their KVCXO3-1s and record calibration data.

The best part about this business is that if you really care about
your accuracy, you will have to have this done every year (or more
often) because as the crystals age, their resonant frequency can
change.

--Vernon

On Thu, Jun 9, 2011 at 1:51 PM, Wayne Burdick <[hidden email]> wrote:
> I'm suggesting that the only way we can handle this at present is to
> allow users to generate their own data.
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Dave New, N8SBE

Re: [K3] K3EXREF K144REFLK and K144XV

In reply to this post by Tim Taylor

Geez, I gotta quit relying on my memory. From the Dallas datasheet:

The output is accurate to ±2ppm (±1 min/yr) from 0°C to +40°C and to
±7.5ppm
(±4 min/year) from -40°C to 0°C and from +40°C to +85°C.

Not exactly .5 ppm, but this is for a different application (RTC) than
what we were discussing.

Beats our current ±30ppm on our existing time-of-day design, which
works out to ±80 seconds/month.

I'd certainly be happy if the K3 clock would stay within ±1 min/yr...

73,

-- Dave, N8SBE

> -------- Original Message --------
> Subject: Re: [Elecraft] [K3] K3EXREF K144REFLK and K144XV
> From: "Dave New, N8SBE" <[hidden email]>
> Date: Thu, June 09, 2011 2:51 pm
> To: "Wayne Burdick" <[hidden email]>
> Cc: [hidden email], Tim Taylor <[hidden email]>
>
>
> Sorry, Seiko is the RTC -- google for S35390A_E.pdf
>
> Dallas (Maxim) is the TXCO supplier -- google for DS32kHz-DS32KHZS.pdf
>
> 73,
>
> -- Dave, N8SBE
>
> > -------- Original Message --------
> > Subject: Re: [Elecraft] [K3] K3EXREF K144REFLK and K144XV
> > From: Wayne Burdick <[hidden email]>
> > Date: Thu, June 09, 2011 2:08 pm
> > To: "Dave New, N8SBE" <[hidden email]>
> > Cc: [hidden email], "Tim Taylor" <[hidden email]>,
> > "David Pratt" <[hidden email]>
> >
> >
> > Dave,
> >
> > The 49 MHz "1-ppm" oscillator is a TXCO, and it works well (0.5 ppm
> > from 0 to 50 C). Originally we thought we would not be able to hit
> > this target without adding firmware-based correction.
> >
> > I did implement the firmware correction, but I wasn't happy with it,
> > because it didn't provide much of an improvement beyond 0.5 ppm with
> > all oscillators tested. What I found is that I had to create data for
> > every 1 degree C, rather than every 5 degrees, in order to get to hit
> > a more aggressive 0.25 ppm target. But the manufacturer of the TCXO
> > had predicted that 5-degree data points would be sufficient for the
> > algorithm, and that is what they supply with the oscillators. We could
> > ask the for 1-degree data, but that would increase the cost (not to
> > mention create five times as much data). It would also not be of much
> > help to those who already had 1-ppm TCXOs installed.
> >
> > What we could do in a future release is provide a way for customers to
> > manually generate and use 1-degree data. Call it "Method 4." It seems
> > a bit onerous, but here's the idea: First, you'd put your K3 in the
> > refrigerator long enough to get to 0C, or the desired low operating
> > temp. Next, set the rig up with an accurate frequency counter
> > connected to the output of the oscillator, and put the cover back on,
> > or at least part of the way on (the freq counter cable has to come out
> > at the back or side). Then, as the radio heats up, write down the
> > oscillator frequencies for each 1-degree point. When it gets as hot as
> > it's going to get due to ambient temperature, turn on a hot lamp or
> > hair dryer and aim it at the top cover, about where the oscillator is.
> > Continue heating and logging data until the desired max operating
> > temperature is reached.
> >
> > You could then enter this info into a revised oscillator calibration
> > data screen in K3 Utility. I'd have to add the firmware necessary to
> > allow the oscillator to be updated continuously based on 1-degre data.
> >
> > This is a long answer to your question. It begs the further question,
> > Would anyone bother?
> >
> > 73,
> > Wayne
> > N6KR
> >
> >
> > On Jun 9, 2011, at 10:36 AM, Dave New, N8SBE wrote:
> >
> > > Wayne,
> > >
> > > What I guess I don't understand is why the TXCO functionality was
> > > never
> > > finished. Seems like that would help a number of accuracy/calibration
> > > issues, and I bought the .5 ppm option expecting that it would be
> > > useful.
> > >
> > > I'm disappointed in what appears to be a decision to abandon finishing
> > > that project.
> > >
> > > On a related note, it wouldn't hurt to do something to fix the real
> > > time
> > > clock, so I don't have to keep syncing it with my laptop to keep it
> > > reasonably on time.
> > >
> > > Thanks,
> > >
> > > -- Dave, N8SBE
> > >
> > >> -------- Original Message --------
> > >> Subject: Re: [Elecraft] [K3] K3EXREF K144REFLK and K144XV
> > >> From: Wayne Burdick <[hidden email]>
> > >> Date: Thu, June 09, 2011 1:02 pm
> > >> To: David Pratt <[hidden email]>
> > >> Cc: [hidden email], Tim Taylor <[hidden email]>
> > >>
> > >>
> > >> I'm on the hook for this. I'll send out test code when it's ready.
> > >>
> > >> 73,
> > >> Wayne
> > >> N6KR
> > >>
> > >> On Jun 9, 2011, at 9:36 AM, David Pratt wrote:
> > >>
> > >>> Tim - My understanding is that the K3EXREF does not stabilise the
> > >>> transverter offset. I believe this is planned in a future K3
> > >>> firmware
> > >>> upgrade, but as far as I am aware this has not yet happened.
> > >>>
> > >>> 73 de David G4DMP
> > >>>
> > >>> In a recent message, Tim Taylor <[hidden email]> writes
> > >>>> So right now, the K3EXREF will stabilize the frequency of the basic
> > >>>> radio;
> > >>>> however, it will not stabilize the frequency of the K144XV. It is
> > >>>> my
> > >>>> understanding that the firmware for the K144XV is "in the que".
> > >>> --
> > >>> + - - - - - - - - - - - - - - - - +
> > >>> | David M Pratt, Kippax, Leeds. |
> > >>> | Website: http://www.g4dmp.co.uk |
> > >>> + - - - - - - - - - - - - - - - - +
> > >>>
> > >>>
> > >>>
> > >>> ______________________________________________________________
> > >>> Elecraft mailing list
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> > >>>
> > >>> This list hosted by: http://www.qsl.net
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> > >>
> > >> ______________________________________________________________
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