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Re: [Amps] RMS VS Peak VS Average power and the Bird 43 wattmeter

To: garyschafer@comcast.net
Subject: Re: [Amps] RMS VS Peak VS Average power and the Bird 43 wattmeter
From: Richard Measures <r@somis.org>
Date: Tue, 29 Mar 2005 08:09:00 -0800
List-post: <mailto:amps@contesting.com>
On Mar 28, 2005, at 5:53 PM, Gary Schafer wrote:

> If it is a peak reading bird it should show the same as with carrier.

... provided that the anode PS is regulated and one takes a reading 
before the coax melts.
>
> 73
> Gary K4FMX
>
> TexasRF@aol.com wrote:
>>
>> And, along a similar vein: If a string of 50% duty cycle dots at say 
>> 50
>> words per minute are transmitted, what should the Bird meter show for 
>> power
>> output compared to full carrier?
>>
>> 73,
>> Gerald K5GW
>>
>> In a message dated 3/28/2005 3:14:31 P.M. Central Standard Time,
>> Dennis12Amplify@aol.com writes:
>>
>> For the  EXPERTS.....,
>>
>> I have a question which I believe will combign the two  most  
>> interesting and
>> informative threads we have had going here on  the reflector  for 
>> quite some
>> time.
>>
>> Why is it that a Bird 43  with a calibrated peak reading kit only  
>> reads
>> THREE times the power  for a peak reading of a 100% modulated AM  
>> waveform,
>> instead
>> of FOUR  times the power as the textbooks all say it  should?
>>
>> Is it because  the 43 is responding to a Half wave  rectified signal 
>> but
>> 'calibrated' to read as though it was responding to  something  else?
>>
>> I believe I have an answer, and it is directly related to  both  
>> threads, but
>> I was hoping for some open discussion of the  subject to see where  
>> it goes,
>> and if it goes in the direction of my  solution or not...
>>
>> Hint: It is a mathematical relationship between the  average response 
>>  of the
>> 43's analog meter movement and the FCC's  definition of power  output.
>>
>> Regards,
>>
>> Dennis  O.
>>
>>
>>
>> It is surely the best thread we have seen on this reflector  in a 
>> long long
>> time. Very comprehensive, informative and lots of fun  to  follow.
>>
>> Thanks to all,
>> Alek. VK6APK
>>
>> At 08:33 PM  27/03/2005,  David Kirkby wrote:
>>
>>> John and Mary Powell wrote in a  different  thread:
>>>
>>>
>>>> Is there a body of opinion out  there that considers  the above 
>>>> subject
>>>
>>> has gone on far too  long, or got out of hand. To me  it appears as 
>>> if
>>> academic  intransigence has got in the way of the  Reflector dealing 
>>> with
>>> it's core business. I noted an earlier plea for  an end to of
>>> this  uninteresting topic, which evolved from a  simple enquiry as  
>>> to
>>> accuracy of the Bird 43 Wattmeter.
>>>>
>>>> Cheers
>>>
>>>> John Powell.   ZL1BHQ
>>>
>>
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>>
>>
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>
>
>
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Rich Measures, 805.386.3734, AG6K, www.somis.org

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