[Amps] cathode emission prediction

[Jeff Blaine]

Thanks John,

Have a nice week break.

Unfortunately, for guys that are using the Russian triodes, getting an 
proper set of curves like what Eimac users enjoy is but only a dream...

I will dig out the C&F again and look it over.  Had not focused much on 
the cathode consideration prior to your suggestions.  Which I really 
appreciate.

73/jeff/ac0c

John Lyles wrote:
>   
>> For the cathode emission limts, do you think there is a way to 
>> characterize this?  Or perhaps infer it from pulse-mode data assuming 
>> comprable CCW data is not available?
>> 73/jeff/ac0c
>>     
>
> Yes, it is available already measured, on the datasheet. Look at the constant current curves on an Eimac sheet, for instance. The  top curve is pretty much the peak that they tested in some fashion, and it is usually a LOT higher than your DC readings. If you are familiar with Tube calculator #5 by Eimac, you know how you have a particular load line that swings back and forth, usually diagonally intersecting the constant currernt curves. These may be cathode or plate current lines, but they are usually close. The peaks of the RF fundamental sinewave will be swinging up into the high current regions on that part of the cycle and down to near cutoff on the other part. Or into cutoff.  This all depends on the class of operation, AB, B and C for instance. Take a look at Care and Feeding on the curves and using them to predict operating points. 
> I am going off line for a week for R&R.
> 73
> John
> K5PRO
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