Amps
[Top] [All Lists]

Re: [Amps] R. MEASURES PRAYERS ANSWERED

To: R L Measures <r@somis.org>, Gudguyham@aol.com
Subject: Re: [Amps] R. MEASURES PRAYERS ANSWERED
From: Peter Chadwick <g3rzp@g3rzp.wanadoo.co.uk>
Reply-to: g3rzp@g3rzp.wanadoo.co.uk
Date: Sun, 4 Jun 2006 10:26:26 +0200 (CEST)
List-post: <mailto:amps@contesting.com>
Rich said:
>1.  Pi-networks are never operated at resonance, they are operated  
close to resonance.  Low-pass Pi-networks resonate a bit lower than  
the operating freq and high-pass Pi-networks resonate above it.<
If it isn't resonant i.e. volts and amps are in phase, then you won't get 
maximum output and will likely get worse IMD. I am aware that the US Extra 
Class licence exam defines resonance as XL = XC, but this is only an 
approximation, and falls apart very badly when the working Q is low. If you use 
the only definition of resonance which holds up under all conditions i.e. the 
input impedance of the network is resistive (as far as the tube sees it - 
strays will have some effect if you calculate and compare with reality, 
especially on the higher bands), then the pi network is resonant. So is the L 
network, but if you use XL = XC, then both cases suggest that the circuit isn't 
resonant.
Operating into a non-resonant load leads to an elliptical load line - see 
Pappenfus et al.

73
Peter G3RZP
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps

<Prev in Thread] Current Thread [Next in Thread>