Re: QRP kit amplifiers

Gordon Gibby
 

Maybe jump over all the other amplifiers and take advantage of the low pass filter’s after the final?




On Mar 31, 2019, at 14:58, ajparent1/KB1GMX <kb1gmx@...> wrote:

On Sun, Mar 31, 2019 at 11:15 AM, Laurence Oberman wrote:
I will start with removing C84 to break the circuit and putting a 1uf
in series input to the 2n5109.

A ,1uf is sufficient.  Also yes to that connecting point.

I do not expect any improvement in harmonics or spurs as it will faithfully amplify
what is input.  Since I've measured what comes out the low pass filter (33mhz
low pass) at C80 you will get lots of harmonics if CW mode (especially 80/40/20m)
and spurs and harmonics in SSB mode.

Before you hook up the amp hooks your SA up to the C84 point to see what
is going into the amp and come out much bigger.

Allison

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