Hi Ioannis, Hi amgen
Thank you for comments.
For switching capacitor in VCO I shall try CD4066 - it has floating switch output with On resistance 5 ohm.PLL – CD74HC4046A runs on 5VDC, but I shall switch CD4066 control pin with 12 VDC.Suppose capacitor in PLL could be switched on that way.If not I shall try with J111.
Mosfet like a 2N7000 has internally protection diode.As a solution I shall try also to switch with J111 instead which is without internal diode.At the moment I am waiting for ordered elements to arrive so I can make a test.
Keep you informed but need some more time to receive elements and make a proto board.
Best rds. Mike