Re: [TenTec] Ig drift on amps

["Bob McGraw - K4TAX" <RMcGraw@Blomand.net>]

Sorry, I didn't read it that way.  And in a Pi-L network the output C 
components are by design at the midpoint of the network.
Yes, without knowing the values of L, it is a challenge {best guess}  to 
figure the correct values for C and the network center is unknown as well.
73
Bob, K4TAX


----- Original Message ----- 
From: "Dr. Gerald N. Johnson" <geraldj@storm.weather.net>
To: <tentec@contesting.com>
Sent: Sunday, February 08, 2009 10:14 PM
Subject: Re: [TenTec] Ig drift on amps


> On Sun, 2009-02-08 at 21:36 -0600, Bob McGraw - K4TAX wrote:
> > The output of the amp is indeed a Pi-L network.  These work great and 
> > have
> > been in BC transmitters very successfully for years.  I wish more 
> > companies
> > would use Pi-L networks in their amps. Better attenuation of harmonics,
> > lower currents in the coils and components and a better match.  All at 
> > the
> > cost of increased costs.
> >
> > I can't imagine any amp today being able to handle a 300 ohm load on its
> > output at rated power.  That's an SWR of 6:1.
> He was talking about the design impedance at the junction of the Pi and
> the L. Higher than the load Z, lower than the plate Z. 300 to 600 ohms
> are common values for that mid point in the output network. Higher takes
> more L section coil and a higher loaded Q but allows smaller load
> capacitors.
> > 73
> > Bob, K4TAX
>
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