>> 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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