K3 Current Meter

[Scott Ellington]

Has anyone compared the K3 internal current meter to an accurate external meter?  My K3 meter reads about 20A, when the actual current is 23 A, with no accessories connected.  That's a huge error, and it's not linear.  

73,

Scott  K9MA




Scott Ellington
Madison, Wisconsin
USA



______________________________________________________________
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

[Jim Rogers, W4ATK]

Ok, when was the meter you consider to be accurate last certified? Or were you taking the word of the meter on your power supply......  I am sorry, as a former certification lab technician, I  could not help myself.


On Feb 28, 2011, at 11:48 AM, Scott Ellington wrote:

> Has anyone compared the K3 internal current meter to an accurate external meter?  My K3 meter reads about 20A, when the actual current is 23 A, with no accessories connected.  That's a huge error, and it's not linear.  
>
> 73,
>
> Scott  K9MA
>
>
>
>
> Scott Ellington
> Madison, Wisconsin
> USA
>
>
>
> ______________________________________________________________
> 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

JIM ROGERS, W4ATK
[hidden email]
http://web.me.com/jimrogers_w4atk
K3/100 P3
K2/10




______________________________________________________________
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

[Guy, K2AV]

And your reason for presuming the "actual current" at 23 A is ????.   What
are you using to measure that?   The meter on your power supply?  A Fluke
meter that has a 25A range or ?

First calibrate ADC REF on the K3 CONFIG menu (TECH MD must first be set to
"on") per the procedure on page 53 of the manual. You can scan for the
manual's pdf file for ADC REF  .

This calibration sets up a reference voltage inside the K3.  But do it with
an accurate DVM.  Then see what the K3's internal shunt voltage is reading.
 That's what you are actually seeing.

73, Guy.

On Mon, Feb 28, 2011 at 12:48 PM, Scott Ellington <
[hidden email]> wrote:

> Has anyone compared the K3 internal current meter to an accurate external
> meter?  My K3 meter reads about 20A, when the actual current is 23 A, with
> no accessories connected.  That's a huge error, and it's not linear.
>
> 73,
>
> Scott  K9MA
>
>
>
>
> Scott Ellington
> Madison, Wisconsin
> USA
>
>
>
> ______________________________________________________________
> 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

[Scott Ellington]

The measurement is quite accurate, and the ADC reference is OK.  Sorry I didn't point that out originally.  I did get some data from Gary, which shows that his K3 current meter is much more accurate than mine.  

The meter accuracy itself isn't really important, but the error may be limiting output power, as the High Current error occurs at a lower current than intended.

73,

Scott  K9MA



On Feb 28, 2011, at 3:40 PM, Guy Olinger K2AV wrote:

> And your reason for presuming the "actual current" at 23 A is ????.   What are you using to measure that?   The meter on your power supply?  A Fluke meter that has a 25A range or ?
>
> First calibrate ADC REF on the K3 CONFIG menu (TECH MD must first be set to "on") per the procedure on page 53 of the manual. You can scan for the manual's pdf file for ADC REF  .
>
> This calibration sets up a reference voltage inside the K3.  But do it with an accurate DVM.  Then see what the K3's internal shunt voltage is reading.  That's what you are actually seeing.  
>
> 73, Guy.  
>
> On Mon, Feb 28, 2011 at 12:48 PM, Scott Ellington <[hidden email]> wrote:
> Has anyone compared the K3 internal current meter to an accurate external meter?  My K3 meter reads about 20A, when the actual current is 23 A, with no accessories connected.  That's a huge error, and it's not linear.
>
> 73,
>
> Scott  K9MA
>

Scott Ellington
Madison, Wisconsin
USA



______________________________________________________________
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