SB-102 with Lo-Pass filter

[Bill Coleman AA4LR]

On 7/15/98 4:58 PM, Robert P. Okas at vintage at BEST.COM wrote:

>Hi Allen,
>
>    A PI-net is indeed a lowpass filter. It darned well better be since
>it's also used to match the output of a Class-C final to the load. We all
>know that Class C is anything but linear!

Last time I looked, an SB-102 used a Class AB1 amplifier in the final,
even for CW. An AB1 amplifier is quite linear.

Suffice it to say that a LP filter will only help an RFI problem that is
caused by harmonics from the transmitter. If the RFI problem is caused by
fundamental overload (likely scenario for TVI in a cabled area), or
rectification (as in being heard on a telephone), then an LP filter will
do absolutely nothing.

In general, an LP filter may not be necessary, but it can't hurt.



Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at radio.org
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901

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