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K3S & 2m Internal Transverter Calibration Problem Using External Reference

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stengrevics

K3S & 2m Internal Transverter Calibration Problem Using External Reference

I am using an external reference to lock the K3S' frequency. The resulting frequency is 100% accurate on the low bands and on 6 meters. However, on 2 meters, the frequency is approximately 800 Hz low.

The manual states that using an external reference will lock the frequency but that it will be somewhat less accurate (not 800 Hz less accurate). There is no procedure given for calibration with an external reference oscillator.

I suppose I could play with the offset, but that seems hit or miss. I would appreciate any suggestions.

73,

John
WA1EAZ
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stengrevics

Re: K3S & 2m Internal Transverter Calibration Problem Using External Reference

Hi Mike,

Yes, the Phase Lock option is installed according to instructions from Elecraft. But, I am 800 Hz off.

73.

John
WA1EAZ

> On Aug 11, 2020, at 10:51 AM, Mike Harris <[hidden email]> wrote:
>
> Hi John,
>
> Can we assume that the K144XV Oscillator Phase Lock (option) is installed. It works for me.
>
> Regards,
>
> Mike VP8NO
>
> On 11/08/2020 09:20, John Stengrevics wrote:
>> I am using an external reference to lock the K3S' frequency. The resulting frequency is 100% accurate on the low bands and on 6 meters. However, on 2 meters, the frequency is approximately 800 Hz low.
>> The manual states that using an external reference will lock the frequency but that it will be somewhat less accurate (not 800 Hz less accurate). There is no procedure given for calibration with an external reference oscillator.
>> I suppose I could play with the offset, but that seems hit or miss. I would appreciate any suggestions.
>> 73,
>> John
>> WA1EAZ

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hdv

Re: K3S & 2m Internal Transverter Calibration Problem Using External Reference

In reply to this post by stengrevics

Hi john,

Correction of the frequency for HF/6 takes place at synthesizer/DSP level (Elecraft has not answered my questions where exactly) and takes the frequency deviation of the main TCXO into account. So this does not correct the TCXO itself.

The 2 meter K144RFLK locks directly to the main TCXO. As said, this frequency cannot be corrected.

The 2 meter transverter does not "communicate" with the rest of the K3 as well so no correction on synthesizer/DSP level takes place and any TCXO frequency deviation will show up on 2 meters.

The 800 Hz cannot be corrected.

You could change the TCXO by a more accurate one.

73 Henk

PA0C

Henk

On Tue, Aug 11, 2020 at 2:21 PM +0200, "John Stengrevics" <[hidden email]> wrote:

I am using an external reference to lock the K3S' frequency. The resulting frequency is 100% accurate on the low bands and on 6 meters. However, on 2 meters, the frequency is approximately 800 Hz low.

The manual states that using an external reference will lock the frequency but that it will be somewhat less accurate (not 800 Hz less accurate). There is no procedure given for calibration with an external reference oscillator.

I suppose I could play with the offset, but that seems hit or miss. I would appreciate any suggestions.

73,

John
WA1EAZ
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stengrevics

Re: K3S & 2m Internal Transverter Calibration Problem Using External Reference

Hi Henk,

Thanks for that info. That does make me think I could adjust the offset on the Config menu to account for the 800 Hz, no?

73,

John
WA1EAZ

> On Aug 11, 2020, at 2:18 PM, Henk de Vries <[hidden email]> wrote:
>
> Hi john,
>
> Correction of the frequency for HF/6 takes place at synthesizer/DSP level (Elecraft has not answered my questions where exactly) and takes the frequency deviation of the main TCXO into account. So this does not correct the TCXO itself.
>
> The 2 meter K144RFLK locks directly to the main TCXO. As said, this frequency cannot be corrected.
>
> The 2 meter transverter does not "communicate" with the rest of the K3 as well so no correction on synthesizer/DSP level takes place and any TCXO frequency deviation will show up on 2 meters.
> The 800 Hz cannot be corrected.
>
> You could change the TCXO by a more accurate one.
>
> 73 Henk
> PA0C
>
> Henk
>
>
>
>
> On Tue, Aug 11, 2020 at 2:21 PM +0200, "John Stengrevics" <[hidden email] <mailto:[hidden email]>> wrote:
>
> I am using an external reference to lock the K3S' frequency. The resulting frequency is 100% accurate on the low bands and on 6 meters. However, on 2 meters, the frequency is approximately 800 Hz low.
>
> The manual states that using an external reference will lock the frequency but that it will be somewhat less accurate (not 800 Hz less accurate). There is no procedure given for calibration with an external reference oscillator.
>
> I suppose I could play with the offset, but that seems hit or miss. I would appreciate any suggestions.
>
> 73,
>
> John
> WA1EAZ
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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hdv

Re: K3S & 2m Internal Transverter Calibration Problem Using External Reference

Hi John,

In case you are only interested in 2 meters you can and have an accurate readout on the band

Be aware that all hf + 6m will shift as well and will no longer be accurate.

73 Henk

Henk

On Tue, Aug 11, 2020 at 8:28 PM +0200, "John Stengrevics" <[hidden email]> wrote:

Hi Henk,
Thanks for that info. That does make me think I could adjust the offset on the Config menu to account for the 800 Hz, no?
73,
JohnWA1EAZ

On Aug 11, 2020, at 2:18 PM, Henk de Vries <[hidden email]> wrote:
Hi john,

Correction of the frequency for HF/6 takes place at synthesizer/DSP level (Elecraft has not answered my questions where exactly) and takes the frequency deviation of the main TCXO into account. So this does not correct the TCXO itself.

The 2 meter K144RFLK locks directly to the main TCXO. As said, this frequency cannot be corrected.

The 2 meter transverter does not "communicate" with the rest of the K3 as well so no correction on synthesizer/DSP level takes place and any TCXO frequency deviation will show up on 2 meters.

The 800 Hz cannot be corrected.

You could change the TCXO by a more accurate one.

73 Henk

PA0C

Henk

On Tue, Aug 11, 2020 at 2:21 PM +0200, "John Stengrevics" <[hidden email]> wrote:

I am using an external reference to lock the K3S' frequency. The resulting frequency is 100% accurate on the low bands and on 6 meters. However, on 2 meters, the frequency is approximately 800 Hz low.

The manual states that using an external reference will lock the frequency but that it will be somewhat less accurate (not 800 Hz less accurate). There is no procedure given for calibration with an external reference oscillator.

I suppose I could play with the offset, but that seems hit or miss. I would appreciate any suggestions.

73,

John
WA1EAZ
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w4sc-2

Re: K3S & 2m Internal Transverter Calibration Problem Using External Reference

In reply to this post by stengrevics

Read the following:

1) K144XV manual pp20
2) K144XV Reference Oscillator Phase Lock Option Manual. Pp 11

Once the K3S 49MHz oscillator is calibrated, leave alone.

The LOs (plural,,,116MHz and 118MHz) are locked to the 10MHz reference (which, depending where you are in the 2M band). If there is no 10MHz reference applied, keeping the desired accuracy may be impossible over a range of temperature.

You should be able to attain +- 10Hx accuracy according to the K144XV manuals. If the 800Hz error cannot be corrected by the procedure outlined, I suggest contact Elecraft support.

Ben W4SC

Sent from Mail for Windows 10

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stengrevics

Re: K3S & 2m Internal Transverter Calibration Problem Using External Reference

Ben,

The K144XV & Phase lock calibration steps have already been performed. The problem arises when using an external reference oscillator.

Elecraft support emailed.

Thanks,

John
WA1EAZ

> On Aug 11, 2020, at 7:14 PM, w4sc <[hidden email]> wrote:
>
> Read the following:
>
> K144XV manual pp20
> K144XV Reference Oscillator Phase Lock Option Manual. Pp 11
>
> Once the K3S 49MHz oscillator is calibrated, leave alone.
>
> The LOs (plural,,,116MHz and 118MHz) are locked to the 10MHz reference (which, depending where you are in the 2M band). If there is no 10MHz reference applied, keeping the desired accuracy may be impossible over a range of temperature.
>
> You should be able to attain +- 10Hx accuracy according to the K144XV manuals. If the 800Hz error cannot be corrected by the procedure outlined, I suggest contact Elecraft support.
>
> Ben W4SC
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10

w4sc-2

Re: K3S & 2m Internal Transverter Calibration ProblemUsing External Reference

Are you seeing the 800Hz error in both band segments (144 and 146)?

Looking at the schematics, there is an adjustment for each LO, but this must be a factory adjustment as there is no mention of them in manuals.

Good to contact support. All would be interested in the resolution.

73 de Ben W4SC

Sent from Mail for Windows 10

From: John Stengrevics
Sent: Tuesday, August 11, 2020 21:54
To: w4sc
Cc: [hidden email]
Subject: Re: [Elecraft] K3S & 2m Internal Transverter Calibration ProblemUsing External Reference

Ben,

The K144XV & Phase lock calibration steps have already been performed. The problem arises when using an external reference oscillator.

Elecraft support emailed.

Thanks,

John
WA1EAZ

On Aug 11, 2020, at 7:14 PM, w4sc <[hidden email]> wrote:

Read the following:

1. K144XV manual pp20
2. K144XV Reference Oscillator Phase Lock Option Manual. Pp 11

Once the K3S 49MHz oscillator is calibrated, leave alone.

The LOs (plural,,,116MHz and 118MHz) are locked to the 10MHz reference (which, depending where you are in the 2M band). If there is no 10MHz reference applied, keeping the desired accuracy may be impossible over a range of temperature.

You should be able to attain +- 10Hx accuracy according to the K144XV manuals. If the 800Hz error cannot be corrected by the procedure outlined, I suggest contact Elecraft support.

Ben W4SC

Sent from Mail for Windows 10

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KeithWE6R

Re: K3S & 2m Internal Transverter Calibration Problem Using External Reference

Administrator

In reply to this post by stengrevics

Make sure the RefLock board is seated all the way down in the K144 and
cabled correctly (there is a BAD diagram floating around).
Check for current Firmware, FW of BOTH the radio AND the K144XV! Older
did not support the RefLock!
Check the TMP socket(s) on the K144XVREFLOCK for shoved in centers, they
can get pushed in.
Make sure the TAP 0 (zero) in the XV1 OFS menu says REFLOCK and not NOR.
Does the external ref give you an asterisk blinking in the REF CAL
config menu after about 15 seconds or less?
If so, the RefLock in the K144 should lock to that and be very accurate.
HOWEVER;
What is the main REF CAL number when calibrated? If it is too far away
from 49.380.000 the RefLock will not be able to pull the K144 onto
frequency.
If it is below 49.379.500 or so it could be the problem, in which case
you need a new main oscillator.
If the external Reference is being used (EXREF) then there is no need
for the main oscillator to be the high stability KCTXO3-1.
Put the low stability one back in if you upgraded and see if it's number
is closer to 49.380

If you do have the high stability KTCXO3-1, and the number is too far
out, you can tweak the cap under the sticker to MAYBE get it close enough.
Go slow on tuning, and don't set it too close to the "wrap" point or a
temp change may make it go out of lock.
IE On 6meters, set radio and accurate signal generator to get a nice
signal, disable the EXREF, and tweak bringing the 49.379.xxx freq closer
to 49.38.
It will only go so far an go out of lock, go back a little until it
locks, then maybe a tad bit back to allow for temp changes.
Keith WE6R Elecraft K3 Tech.
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