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Re: New K3 built - can I reset the 5w calibration?

Posted by VE3GNO Daniel on Dec 09, 2011; 4:09pm
URL: http://elecraft.85.s1.nabble.com/New-K3-built-can-I-reset-the-5w-calibration-tp7076112p7078738.html

The 5% accuracy of the wattmeter is not constant over the entire range from the 1st division of the scale coresponding to 1W or so to last 100W and can variate, they say is up to 5%. Now where is the best precision hard to say but might be in the middle range or full scale.


VE3GNO/YO3GJC Daniel


________________________________
From: Eugene Balinski <[hidden email]>
To: [hidden email]; [hidden email]
Sent: Friday, December 9, 2011 10:32:44 AM
Subject: Re: [Elecraft] New K3 built - can I reset the 5w calibration?

>From what I understand, the meter is rated at 5% of the
**full scale** rating according to Bird.  Full scale
rating, is the rating on the slug. 

That would mean that for a meter with a 100W slug, your
accuracy is +/- 5W (5%).  So, if your wattmeter is reading
50W, the actual RF power could actually be 45 or 55 W....

73
K1NR


On Fri, 09 Dec 2011 09:08:55 -0500
Mike <[hidden email]> wrote:

> Wait.
>
> Using a 100W slug, if you get a reading of 100 watts, the
> real power would be between
> 95 and 105 watts, right?
> If you get a reading of 50 watts the real power would
> fall in a range of less than 45
> to 55 watts?
>
> Not if the 5% at full scale is the best accuracy.  Or did
> I misunderstand what you said?
>
> 73, Mike NF4L
>
>
> On 12/8/2011 11:59 PM, Eugene Balinski wrote:
> > The accuracy of Bird elements is typically  +/- 5% of
> the
> > full scale value.  For a 100 W Slug, that is +/- 5
> Watts.
> >    So theoretically speaking, with 5W in, and 0
> registered
> > on the meter, the meter is still within its rated
> accuracy.
> >
> >
> > Additionally on the model 43 meter, there is meter
> scale
> > end compression.  To get the most accurate reading, one
> > would want to have the 5W reading at the middle of the
> > meter range, which means that one would want a 10W
> slug.
> >  Unfortunately I do not believe that Bird makes a 10W
>  HF
> > slug any more.  Perhaps they need an Elecraft W2 ??
> >
> > 73
> > K1NR
> >
> >
> > On Thu, 8 Dec 2011 16:47:27 -0600
> >  Nate Bargmann<[hidden email]>  wrote:
> >> > From my experience, trying to measure 5W with a 100W
> >> element leads to
> >> very inaccurate readings.  The Bird is most accurate
> when
> >> the reading is
> >> as near to full scale as possible.  That means a 5W HF
> >> element (is that
> >> even available?) would be ideal provided no more than
> 5W
> >> is put through
> >> the meter.  A 10W element would be less accurate but
> >> provide a safety
> >> margin for the meter.  Even better would be to have
> both
> >> elements and
> >> use the 10W one to get in the ballpark and the 5W one
> for
> >> a final check.
> >>
> >> 73, de Nate N0NB>>
> >>
> >> --
> >>
> >> "The optimist proclaims that we live in the best of
> all
> >> possible worlds.  The pessimist fears this is true."
> >>
> >> Ham radio, Linux, bikes, and more: http://www.n0nb.us
> >>
>
>
>
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