[Elecraft] Rescaling the W2?

[Michael Blake]

Alan, while I do not own a W2 it would seem that the pickup coils in the sensor could be reduced in turns by the correct amount to lower the coupling loss loss by 3 dB.  Would not the rest of the W2 work correctly at the 3 dB (or whatever you choose) lower power level?

Michael Blake - K9JRI



> On Nov 20, 2015, at 12:07 PM, Alan <n1al at sonic.net> wrote:
> 
> I just tested it.  The maximum you can set the W2 calibration value to is 650.  (Using the ">" and "+" RS-232 commands)  That causes the wattmeter to read about 60% high on my W2.  So with the W2 set to read 2000W full scale, the actual full scale would be about 1250W.
> 
> Or you could go in the other direction.  The minimum calibration value is 350, which causes the power to read about 47% (on my unit).  With the W2 set to read 200W full scale it would actually be about 425W full scale.
> 
> Alan N1AL
> 
> 
> On 11/20/2015 07:15 AM, Cliff Frescura wrote:
>> I find the scaling awkward as well.  My W2 is placed on the input side of my
>> KPA500 and it seems that dividing the scale by two might do the trick.  I've
>> not looked at the schematic, but wonder if it could be tricked by a resistor
>> divider in the sensor line.
>> 
>> 73,
>> 
>> Cliff K3LL
>> 
>> -----Original Message-----
>> From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Don
>> Wilhelm
>> Sent: Friday, November 20, 2015 5:55 AM
>> To: Scott Townley; elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] Rescaling the W2?
>> 
>> Scott,
>> 
>> I believe that would require a new sensor and firmware to support it.
>> Popular scales on wattmeters are 200 watts and 2000 watts full scale, so you
>> are not going to get much better with another brand product.
>> The W2 used with its utility program can give you more resolution, but then
>> using the Utility when mobile would not be advisable.
>> 
>> 73,
>> Don W3FPR
>> 
>> On 11/20/2015 8:32 AM, Scott Townley wrote:
>>> I know the W2 can be "dialed in" to match one's personal standard,
>>> but...can it be completely rescaled?
>>> I use the K3/KPA500/W2 mobile, and the KPA500 is mounted in my pickup
>>> bed so the W2 is the only system meter available at the operating
>>> position.  However, the 2's scaling doesn't give me much display
>>> dynamic range...the KPA500 will only light 5 of the 17 LEDs at full
>>> power.
>>> It would be far more useful for me to have the meter scaled to 600W
>>> say...then the 15th LED would be 450W.  Even scaling it to 1000W would
>>> give me more than half the display range.
>>> 
>>> 
>> 
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