[Elecraft] W2 Wattmeter 440 band accuracy?

[Don Wilhelm]

Michael,

In general, digital wattmeters have the same accuracy at any point on 
the scale - unlike analog wattmeters for which the accuracy is stated as 
a percentage of the full scale reading.  On a 20 watt scale, a 25% error 
would be up to 4 watts!

You might want to look at the specs for that 440 MHz transmitter as 
well.  If it 2.6 dB or so, getting 2.8 watts out for a 5 watt setting 
may be what you can expect.

73,
Don W3FPR

On 7/30/2017 4:59 PM, Michael via Elecraft wrote:
> OK so I am trying to measure around 5 Watts or so on the W2's 20 Watt
> scale.  The spec's for the W2 directional couplers are listed at 0.5 dB
> accuracy.  Is this anywhere or just at full scale? How much could it  be off at
> only 25% of full scale?
>   
> Trying to decide if the 2.8 Watts I am reading at 440 MHz on high power is
> too low with a spec of 5 Watts output!  If it is I can send it back to the
> place of purchase to be checked and exchanged if necessary.
>   
> There seems to be no problem on the 2 Meter band at only 25 % of scale (5
> Watts) reading....just on 440.
>   
> Michael
> n2zdb
>   
>   
>   
>   
>   
>   
> In a message dated 07/30/2017 12:36:49 P.M. Eastern Daylight Time,
> elecraftcovers at gmail.com writes:
> 
>   
> 
> 
> The accuracy of a Bird Model 43 is +/- 5% of full scale.  The meter  scale
> is not
> linear and produces the best read accuracy in the bottom portion of the
> meter's
> scale.
> 
> 
> There are numerous watt meters on the market today that are more  accurate.
>   
> 
> 
> FWIW  73!
> 
> 
> Ken Kopp - K0PP
> 
> ----------------------------------------------------------------------------
> --------------------------
> On Sun, Jul 30, 2017 at 9:23 AM, Michael Walker <va3mw at portcredit.net>
> wrote:
> 
> The  only way to get the answer you wish is to compare it to a bench
> standard  like a bird watt meter.
> 
> Beyond that you are just guessing.   Sorry
> 
> Mike va3mw
> 
> 
> On Sun, Jul 30, 2017 at 11:18 AM,  Michael via Elecraft <
> elecraft at mailman.qth.net>  wrote:
> 
>> Measurement is in analog mode.....should have made that  clear or not even
>> mentioned a digital radio!
>>
>>   Michael
> 
> 
> 
> 
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