Thanks for all the ideas gents, I need to get some parts from Diz and
Rex and start experimenting. Hopefully after Christmas.
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On Sun, Dec 15, 2019 at 7:04 AM Chuck Carpenter <w5usj@...> wrote:
OK, last time, I promise.
Jerry and All,
I expect we've been thinking grapefruit and tangerines...related but not the same...8^)
Varactors used to tune an entire AM or FM band with a max C of 350pF or so and a min C of about 30pF at 12 V. I'd expect them to be like you described.
The varactors I'm using, BB910 or MV209, have a max C of about 60pF or so and a min C of about 6pF at 12 V, same percentages but minimal effect in the circuit where used. My choice of these two (or other similar) was related to the 60pF section of a polycon variable often used in VXOs.
Anyway, Fun Stuff...
On Sat, Dec 14, 2019 at 09:14 AM, Jerry Gaffke wrote:
What we are saying is that for most such designs where the varactor might be trying to
give a range of 300khz instead of 3khz, the stability will be 100 times worse than what you experience.
--
Chuck, W5USJ (ex K2OFN)
Point, Rains Co, TX EM22cv
