[Amps] Real time tests to see if an RF transformer is

[Jim Thomson]

Date: Fri, 16 Jun 2017 12:44:43 +0100
From: Chris Wilson <chris at chriswilson.tv>
To: amps at contesting.com
Subject: Re: [Amps] Real time tests to see if an RF transformer is
saturating?


<Is heat produced in an LPF indicative of wasted energy to the antenna,
<or  is  it just the function of dissipating the unwanted harmonics and
<will be produced by any filter designed to remove them?


> Chris.

###  AFAIK, if the LPF heats up, its components are not sized correctly to handle the
fundamental.   The harmonics are reflected back towards the PA.  The harmonics are
not absorbed by the LPF, nor are they routed through to.... ground.  But here we  are talking about
136 khz... so the cut off would have to be well below   272 khz, but higher than 136 khz.  Is that
even doable ?   How much harmonic suppression is required ?  How much attenuation is 
readily achievable, in a practical LPF circuit.   I can well imagine a LPF  with a cut off of say
150 khz, having component values that are bizzare. 

Jim VE7RF