[Elecraft] RE : Varicap

[Lagier Gerard]

Using a very low voltage on the varicap is not recommended because it =
reduces significantly the Q of the tank circuit.

73

G=E9rard F6EHJ

> Recently I asked about the recommendation to reduce the size of the
> resistor in the circuit between the DAC and the varicaps used in the =
PLL
> Reference Oscillator. Wayne explained that they rectify some of the =
r-f,
> producing a d-c bias as a result. With the 10k value the circuit
> originally used, the DAC couldn't pull the tuning voltage down much
> below 0.5 vdc.=20
>=20
> From that I'd conclude that those varicaps make pretty good =
rectifiers
> at the frequencies used in the K2 oscillators.
>=20
> Ron AC7AC
> K2 #1289=20