[AMPS] Re:

[Rich Measures]

>
>> >When the FCC measures power, they use a regular peak reading 
>> >meter. .....
>> 
>> �  wanna guess how such meters are ultimately calibrated?.  
>
>No need to guess. Bird calibrates them on a caloric standard. Not 
>a scope in sight.

�  Peak reading instruments calibrated with a bomb-calorimeter?  
>
>Now there is nothing wrong with using a scope, assuming you have 
>one with the required accuracy and resolution and a good load, but 
>it is not a good instrument for use in antenna system to measure 
>power. Errors in power readings occur at both the square of the 
>voltage reading error as well as proportional to load impedance 
>error.

�  and an ordinary wattmeter would not be subject to such errors, Tom?   

>There is absolutely nothing wrong with using a good meter. A few 
>people have wrongly assumed a storage system can't respond fast 
>enough, but that is certainly not correct. The storage system has 
>to track the envelope change rate that follows audio, not the RF 
>cycle change rate. A meter with directional coupler also remains 
>accurate over reasonable load impedance errors. You simply 
>deduct reflected power from forward power.
>
�  Can you explain why this is true?
>
-  cheers, Tom


Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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