[AMPS] Band Pass Filtering

[Harry Brown]

I doubt that a bandpass filter between the rig and the amp or after the amp is going to do much for most distortion caused by solid state amps. 


A bandpass filter may reject some LO leakthru (from band selection oscillators, not from sideband generation oscillators) or other mixer products that get into the transmitter output. It will also reject harmonics of the transmitter or amplifier but not the in-band products of distortions that are generated by the typical over driven solid state amplifier. Bandpass filters just aren't narrow enough for this sort of filtering. 


That's my knee jerk reaction. There are plenty of experts on this list that can straighten me out and I am eager to learn.


73, Harry, W3IIT

=====================================

At 01:27 PM 4/28/99 -0700, you wrote:

>

>Hello Jon et al,

>

>Please permit me to join the chorus of those disdaining the suggestion of

>placing the BPF IN BETWEEN the exciter and the brick amplifier.  Bricks

>are notorious for their non-linearity and no matter how good yours may

>be, I doubt that it is as linear as your exciter. Read that distortion,

>resulting in out of band energy. However, even IF its linearity is equal

>to your exciter, the resulting degradation will be about 3dB.

>

>Therefore, placing the filter at the input  the amplifier will probably

>defeat much of the effectiveness of it...... this also assumes a flat 50

>ohm system for the filter to perform as it is presumably designed.

>

>GL!

>

>Marv, W6FR

>

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