On Wed, 10 Dec 2003 00:26:34 GMT, "W3JDR" wrote:

Paul,
The amount of tuning range is a function of the ratio of Cmax/Cmin. If you
parallel varactors, Cmax will double, but so will Cmin. The ratio hasn't
changed.

Oh bugger. Well how about using varactors with a higher C/V ratio?

If you're not already using a "hyper-abrupt" type of varactor, you should
look into one. They offer a wider capacitance range.

Not sure what you mean by that term, but imagine it amounts to simply
a type with a higher capacitive reaction to applied voltage - as I
mentioned above.

What type of varactor are you using, and what's the frequency of the
resonator? What's the application...linear frequency modulation like FM or
data keying like FSK???

I'm currently using BB149A diodes, but I've got some BBY40s as well,
which might offer more shift per volt; I haven't checked the spec yet.
The fundamental frequency is 8.00Mhz and I need to pull it by +/-32khz
for tuning rather than modulating purposes.

--

"I expect history will be kind to me, since I intend to write it."
- Winston Churchill