K3: 106W on 6m

[Stephen G4SJP]

I have only just noticed that on 6m only, the maximum power output
that can be dialled up is 106W.  110W on all other bands.

Bug or feature I wonder?  Just curious.

Using K3/P3 with latest firmware (4.36)

73 Stephen G4SJP
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[wayne burdick]

Feature :)

This a mathematical curiosity related to the way I handle 6-meter  
power control in firmware. It's on the list somewhere.

Wayne
N6KR


On May 13, 2011, at 12:21 PM, Stephen Prior wrote:

> I have only just noticed that on 6m only, the maximum power output
> that can be dialled up is 106W.  110W on all other bands.
>
> Bug or feature I wonder?  Just curious.
>
> Using K3/P3 with latest firmware (4.36)
>
> 73 Stephen G4SJP
> ______________________________________________________________
> 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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[Jim Brown-10]

On 5/13/2011 12:21 PM, Stephen Prior wrote:
> I have only just noticed that on 6m only, the maximum power output
> that can be dialled up is 106W.  110W on all other bands.

I would be VERY VERY interested in how you can reliably resolve the
difference between 110 watts and 106 watts, or even how you're certain
it's 106 watts.  The accuracy of a Bird 43 wattmeter is 5% of full
scale. To measure 106 watts you need a 250W slug. 5% of that is 12.5
watts.  Where did you get that slug? Do you have any assurance that it
was calibrated?

Perhaps another wattmeter?  Has it been calibrated against a known
standard?  Do you know the frequency response of that meter?  That is,
if it's calibrated at 14 MHz, is it also correct at 28 MHz?  At 50 MHz?  
How do you know?  That is, what voltage or current reference are you
using to determine it?  When and where was that voltage or current
reference last calibrated?

73, Jim Brown K9YC
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[Stephen G4SJP]

Jim,

It's what the display of the K3 is telling me - Wayne has already
replied - it's a (temporary) mathematical curiosity with the firmware.

As a physics professor I'm acutely aware of the measurement problems
you describe!

73, Stephen G4SJP

On 13 May 2011 20:54, Jim Brown <[hidden email]> wrote:

> On 5/13/2011 12:21 PM, Stephen Prior wrote:
>> I have only just noticed that on 6m only, the maximum power output
>> that can be dialled up is 106W.  110W on all other bands.
>
> I would be VERY VERY interested in how you can reliably resolve the
> difference between 110 watts and 106 watts, or even how you're certain
> it's 106 watts.  The accuracy of a Bird 43 wattmeter is 5% of full
> scale. To measure 106 watts you need a 250W slug. 5% of that is 12.5
> watts.  Where did you get that slug? Do you have any assurance that it
> was calibrated?
>
> Perhaps another wattmeter?  Has it been calibrated against a known
> standard?  Do you know the frequency response of that meter?  That is,
> if it's calibrated at 14 MHz, is it also correct at 28 MHz?  At 50 MHz?
> How do you know?  That is, what voltage or current reference are you
> using to determine it?  When and where was that voltage or current
> reference last calibrated?
>
> 73, Jim Brown K9YC
> ______________________________________________________________
> 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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