Re: Simple spur fix

Ripley
 

Hello All,

 

I just finished implementing the 45 Mhz crystal filter fix with the 7:2 impedance matching transformer on the output of the crystal. Now I am hearing myself in the speaker when I transmit and I am seeing the carrier wave on the SA when I push the PTT on the mic.

 

I not sure why the crystal filter mod would be related to these two issues. Anyone experience anything similar?

 

Ripley

 

 

Sent from Mail for Windows 10

 

From: Raj vu2zap
Sent: Sunday, October 14, 2018 2:52 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Simple spur fix

 

Lev, Any experiments on this ?

At 05/09/2018, you wrote:

Would that be a good solution to make the IF amplifier tuned? Like this? Also, change the transistors to BFS17P, this is more suited to RF.

73s de HA5OGL

On Wed, Sep 5, 2018 at 10:46 AM Raj vu2zap < rajendrakumargg@...> wrote:

This fix reduced the spurs by up to 10 db  and requires ONLY ONE part to be added.

There is big change above 10MHz in the board. There is some improvement below also.

 

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