The circuit diagram on the right shows the modifications made by myself to my DB6NT 9cm transverter. All the components annotated in red were either ‘in-stock’ or found in the junk box! C3 is a green ‘Sky’ trimmer which is unfortunately no longer manufactured, but any high-quality trimmer capacitor offering a similar range can be used. To be honest, I have no idea what the varicap diode (D1) is other than it was supplied by Cirkit (sadly no longer in business) and is therefore probably a BB109. However anything similar to an MMBV809L is to be recommended. Because of the nature of this oscillator design, in order to ‘tap off’ some RF for the PLL board, it was necessary to include the INA10386 MMIC in order to provide sufficient buffering and minimum capacitive loading. A MAR-3 can be used as an alternative to the INA10386. I found the output of the MMIC to be +1dBm at 135MHz, which is more than adequate to drive the RF input on the PLL board.
The photograph on the left shows the placement of the added components in relation to the existing LO components. One leg of the MMIC is soldered to a ground pin on the Neosid inductor. The other ground on the MMIC can be soldered to the end of the 150R resistor adjacent to it. A hole was drilled through the board at the junction of R1 and the MMIC to allow coupling of the 135MHz signal via C2 to a connector on the side of the box.
See the photograph, right ->