[sdiy] my VCO not oscillating :(

[Jeff Farr]

Ok, here goes nothing:
U1 is a standard summing network that scales the inputs to 18mV output
for 1mV input, I think (experts?).  Check for this first at the top of
the tempco.  The 1583 will do the exponential conversion sourcing an
exponential current from the linear (18mV/Octave) input to the base.  
Q1 etc I believe to be high frequency compensation (but this is really
just a guess).     hmm... I'm back to the datasheet for the 4302,
FET's operate in enough strange ways I'm really not shure how it will
act here, wheather we should consider the current out from the mirror
or the resulting Vce as more important..  There is alot of feedback in
the circuit after that *scrathes head..*  Experts?