[Amps] Time for New Power Meter

[Joe Subich, W4TV]

 > Rarely does Roger even need correcting, but this is one of those
 > times.

No, Roger is correct.  Bird's specification is 5% *of full scale*.
That means the Bird's accuracy is +/- 125 Watts *anywhere* using a
2500 Watt element.  While in practice the accuracy may be higher
at other places on the scale, the Bird specifications allow that
percentage accuracy may be worse than +/- 5% of the reading below
full scale.

73,

   ... Joe, W4TV


On 2015-05-03 12:40 AM, Bill Turner wrote:
> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>
> On Sat, 02 May 2015 21:39:04 -0400, K8RI wrote:
>
>>
>> The nearest slug I can find to the legal limit is 2500 Watts. 5% is 125
>> watts,  125 watts is a bit over 8% (8.333%...)+/- 125 Watts, or
>> 1500-125=1375 to 1500+125= 1625
>
> REPLY:
>
> Rarely does Roger even need correcting, but this is one of those
> times.
>
> The 125 watt figure is applicable only at full scale, not part scale.
>
> Assuming the meter is linear across its full scale, the 5% spec
> applies to any lower reading. For example, 5% of 1500 watts is 75
> watts, not 125.
>
> Most RF meters are not perfectly linear (especially at low scale
> readings), but for our purposes we can assume they are close.
>
> 73, Bill W6WRT
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