[AMPS] Re: " Kein Rauch ohne Feuer ...."

[measures]

>I do not have the schematics of the Ameritron amps but take a look on the
>schematic of the popular SB 220: If I remember right, you had at the cold
>end of the first plate choke a red 1000pF/5kV?? doorknob beetween the
>junction of the two plate chokes and ground.  

The SB-220 uses a disc ceramic and a doorknob cap in parallel for the HV 
bypass.  The total is 2000pF.  .  The 10uH choke has very little effect 
at 3.5MHz.  At the SB-220's lowest operating frequency of 3.5MHz, 2000pF 
has 22-ohms of Xc -- which is  good enough. .  

>The reactance of the
>combination of  the first plate choke and decoupling condenser  in series is
>in paralell with the C1 and carries rf current on the lower bands . The
>doorknob can take more rf current then a disc capacitor and is a decoupling
>condenser at higher bands. What about the Ameritrons? Do they also have two
>plate chokes in series and a  1000pF decoupling beetween them? Then 1000 pF
>would be OK Mr Rich Measures? Even on 160?
>
Not a low enough Xc.  .  Even 2000pF (44-ohms of Xc) is not much of a 
bypass at at 160m.  

later,  Hans

-  Rich..., 805.386.3734, www.vcnet.com/measures.  
end


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