Re: [amsat-bb] Anyone FT-847 ....

[Mike73@xxxxxxx]

In a message dated 2/21/00 7:54:51 PM Eastern Standard Time, 
jono@enteract.com writes:

> Now, given that 9600 is a much greater signal level than 1200 I have no idea
>  of why you need the extra buffer amp in place at the 9600 baud input side.
>  You'd think that would make the signal going to the mic amp even stronger.
>  I have no idea.  Perhaps the amplifier's purpose is more for impedance
>  matching than signal gain.  I've not really traced the schematic fully in
>  order to understand it.

If you look at the schematic the buffer amp is in circuit all the time but a 
resistor is switched in and out in parallel with the feedback resistor around 
the amp. Looks like amp gain is being changed...... This is why I had 
originally looked at changing the feedback resistor that was switched in for 
9k6 to increase the gain and make it a bit easier to deviate at 9k6.

73,
Mike, N1JEZ
AMSAT #29649
Local Area Coordinator
"A closed mouth gathers no feet."
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