Ok to help clear things up a bit.
The first link http://www.glowfoto.com/viewimage.php?y ... 6&srv=img4
is to the “generic” schematic I was using except using the Z-com VCO and an out put amp. Other changes I made to the front end circuit was I input the output from the BJT in the noise circuit into pin 2 of the LM386 and tie pin 3 to GND. Also in between the op amp stages I used much lower resistors. The schematic shows 10K and when I used 10K the signal was so small it never made it out. Otherwise the signal I see at the tuning input to the VCO is the same as what the original circuit was.
The following links http://www.zcomm.com/PDFs/datasheets/V580ME03-LF.pdf
are for the Z-comm VCO and a evaluation circuit. My VCC set up is the same as there’s. the V tune is from the circuit I described previous, and my RF out is where I connected the spectrum analyzer.
The last link http://www.wj.com/documents/Datasheets/AG603-89.pdf
is for the output amp. The one I was using is basically same as this one only my range is larger otherwise same part. I again used the component set up and values they used in the evaluation schematic which is shown if you scroll down on the part listing.
OK some answers to your questions. I only see the one spike and when I was saying the spec sheet for the VCO had a very flat response I was indeed saying that they show a very linear tuning curve, where as I only see a single spike. I thought maybe it was my front end circuit so first I took out the noise but this did not help. Then I connected my signal generator to the V tune to ramp the tuning voltage and again only saw the single output spike. Finally I selected individual tuning voltages from a well regulated power supply and again only got the one out put. I connected the RF output from the VCO the input of the output amp and reconnected my spectrum analyzer to the output of the amp. I got nothing and the bias resistor from the application schematic just got HOT. So I shut it down.
Hind site what it is the PLL would have been a better choice however already investing $40.00 in VCO’s I need to make due with what I have. There is a well a chance as you mentioned that the VCO has something wrong with it. I have 2 VCO one is for the 800-890 MHZ the other is the 1930-1990 MHZ. All my work as been done with the 800-890 MHZ and I am a bit reluctant to swap in the other as if my front end circuit is the culprit in burning out the original burning up the other one would seem a waste.
I hope this helps? and again your advice is most welcome.