[Amps] ALC setup

[Steve Flood]

I am putting together a simple ALC circuit for my homebrew amp and TS870.  The ALC circuit is found in Orr, K8RA Hanbook amp, K5DR webpage, etc.  It uses a capacitive divider off the RF input line and a variable DC supply.   My TS870 requires a -6 to -20v range for ALC adjustment as per the manual.  So I'm having some trouble figuring out what capacitor values I need in the divider.  I tried this in SPICE but cannot get the modeled circuit to generate negative voltage.

Thanks, 
Steve KK7UV