Re: [Amps] PARALLEL CAPS IN OUTPUT

["Peter Voelpel" <dj7ww@t-online.de>]

It´s quite simple without measurements.

Lets assume the amp is tuned for full legal output into a low SWR on 80m
which needed 1000pf of load capacitance.
Then suddenly the SWR goes sky high because the coax connector went open.

How can the voltage across the load capacitor become 5KV when the reactance
of the load capacitor is just 45 ohms on 3.5MHz?
That would require about 110 Amperes of RF current through that capacitor.
And where is that big current coming from in a 1.5KW amp, not in a 100KW?

73
Peter
  

-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Larry Benko

I'm not sure where this is going.  The original statement was about the 
output capacitor voltage maximums.  Obviously other things in the 
matching network can arc over first but that is a different issue.  For 
that to be valid we need to talk about a specific circuit which is fine 
but it is a different that the original statement about the output 
capacitor voltage vs SWR.

I have made countless measurements on matching networks over the years 
and at the lower frequencies where the circuit is easy to measure the 
measurements match the simulation very well.

You or anyone else can believe what you want but I have made 
measurements which match the theory.  Anyone care to make measurements 
showing what I posted is incorrect?  Do it in a methodical and 
scientific manner and post for all to see.  The measurements can be made 
at the levels available from a signal generator easily.

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