Super VXO

Having completed my VRX-1 receiver and NS-40 transmitter I found that the rock bound version of frequency control a bit limiting. I started digging around and found several articles and schematics for VXO’s that could pull a xtal more than just a few Hertz. SP5DDJ came up with what he calls his PIXIE-3, using a series LC circuit to pull a 80 meter xtal tens of Kilohertz which I thought was incredible.

I’ve messed around with it on a breadboard and can now pull a 3.582 MHz xtal down to 3.500 (and below)  using a 200uf molded inductor and a 10 to 20 uH variable cap. I need to put the circuit onto a dedicated piece of PCB for mounting to a transmitter or receiver. Once on a PCB, the final inductor can cap values will probably change as I have noticed a lot of interaction on the workbench.

I want to also start playing around with a 40 meter version to use with my VRX-1/NS-40 combo rig. This 40 meter project will be more involved as I need it to work from 7.125 to 7.000 MHz.


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