If you want maintain the same Q in PI section you will have to
increase the value of the output capacitor and
increase it's spacing because the impedance at that point is higher than 50
ohms and the peak voltage will
be also.
73
Bill wa4lav
At 09:58 PM 6/27/02 -0500, Phil Clements wrote:
> > Hi All,
> >
> > Wondering about the harmonic attenuation of a Pi L tank vs a standard
> > Pi tank followed by a good quality low pass filter.
> >
> > I am interested in building an amp using a tune and load cap with a good
> > roller inductor in between to eliminate the band switching mess and adding
> > a good low pass filter.
> >
> > How would these two methods compare for spectral purity ???
> >
> > Norm N8NH
>
>Hi Norm, and all the gang!
>The low pass filter would be fine after the Pi, but it would need
>to cut off just above the band in use. You would need one for
>each desired band. Much easier just to add the "L" coil and a
>switch or a roller coil. (can be much smaller than the Pi roller.)
>A 10 uh coil with #12 wire is good for 160-10m @ several KW
>with no heating or sparking.
>
>(((73)))
>Phil, K5PC
>
>
>
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