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[AMPS] Heath SB-230

To: <amps@contesting.com>
Subject: [AMPS] Heath SB-230
From: measures@vc.net (Rich Measures)
Date: Wed, 3 Sep 97 08:37:56 -0800
>> From:          Rich Measures <measures@vc.net>
To: <amps@contesting.com>
>> Date:          Wed, 3 Sep 97 08:01:45 +0000
>
>I wrote:
>> >The grid dissipation is FIVE watts. Rated grid dissipation is reached 
>> >at about 60 mA of grid current in the SB-230.
>
>Rich replied:
>> According to Eimac's constant current curves for the 8873/4/5, the 
>> cathode-to-grid driving voltage is roughly 40V-peak, or 28 V rms.  
>> 28V*0.06A = 1.68W.  . . It sorta looks like that in the Rauchian World,   
>> P=3(I*E).  
>
>It is incorrect to multiply RMS cathode voltage times indicated grid 
>current to find power, since the waveform in the tube is NOT a sine 
>wave.
>
>It might be a good idea, before you pull out your data sheets, to 
>read the instructions on using them. ALL through the guidelines grid 
>power is mentioned as PEAK grid voltage times indicated grid 
>current. 

I have Volume I and Volume II of *Eimac TUBES*, which total over 5 inches 
in thickness and contain specification sheets and constant current curves 
for virtually every non-military power grid tube Eimac makes.  I searched 
throughout, and there appears to be no such statement, Mr. Rauch - - not 
"ALL through" or even in one place.  I find it a bit odd that you have 
not quoted the statement, page number(s), and publication date of the 
alleged Eimac document. 

-  As I recall, you previously claimed that there were some Eimac 
Engineering Bulletins on VHF parasitic-oscillation, but you failed to 
provide the Bulletin numbers.  
......................
Checking the Rauchian Formula:   P=40V-peak multiplied by 0.06A=2.4W of 
grid dissipation  Hmmm.  Mr. Rauch claims that the grid dissipation is 
5W.  ... ... I wonder what I'm doing wrong?  

> ... approximation, the exact 
>value needs to be determined in the actual PA through a fourier 
>analysis.
>
Okay.   I had integral calculus in college.  Have a go at the Fourier 
Analysis, Mr. Rauch, and I'll try to follow along.  
Cheers
Rich---


R. L. Measures, 805-386-3734, AG6K   


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