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[AMPS] L-Net calculations: Am I doing something wrong?

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Subject: [AMPS] L-Net calculations: Am I doing something wrong?
From: (Rich Measures)
Date: Wed, 17 Feb 1999 08:53:36 -0800

>>>The 4-1000A has an output impedance of 4600 Ohms (according to Eimac) at 
>>>5KV anode voltage.
>>?  RL depends on the ZSAC.  With higher idle current, RL decreases.  
>>Using RL=DCV/2 x I-anode, at 0.8A, RL=3.125k-ohms.   Designing for a Q of 
>>15 at 28MHz, a Pi-L with an intermediate Z of 300-ohms, XC1=208 ohms,  
>>C1=26pF.  L1=1.5uH.  L2=0.64uH.  C-load=129pF.  Subtracting 10pF for the 
>>C-anode + stray C, C-tune is 18pF.  The min. C of a UCS-300 is 5pF.  Have 
>>I missed something?
>Whoa!  You suggest running the ZSAC at 0.8 Amps???  

?  0.8A is  indicated I-anode.  ZSAC can be c. 20% of this current -- as 
is the case for 3-500Zs.  .   This makes the cathode a bit easier to 
drive, and it improves linearity.  

>All the specs show it 
>at 100 mA.  You are talking about a HUGE amount of bias current and poor 
>efficiency to boot.
>IMHO, 0.8A of ZSAC isn't really realizable.
?  abundantly true. 

>Did I miss something?
?  You seemingly missed the punctuation marks in what I wrote.

-  cheers, Jon.  


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

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