[TenTec] ALC - How does it work ?

[F8EHJ]

Hello,

After reading jupiter documentation and some posts on the mailing  
list, I don't  understand how does ALC indicator work ?
In CW mode : ALC is lighting with dot or dash transmit.
In SSB mode : ALC is blinking with voice peak, the MIC gain shall be  
adjusted for this.
PSK31 : ALC LED must not be lighted.

I noticed sometimes that (in SSB mode) ALC LED didn't  light even if  
Mic Gain was at maximum. For ALC blinking, I shall decrease output  
power from 100 to 92 %.
I noticed this case when SWR was about 1.6 , 1.7

Why ?

Thanks for your help.

Best 73's

Herve F8EHJ