Spasibo Vasily!
Wow, thanks a lot Todd. There is some great wisdom in your video. You clearly demonstrate that it is possible to build your own stable LC VFOs. Sure, for many the arrival of the synthesizer chip put an end to this kind of project. But some of us still want to fully homebrew all the stages in our rigs, and not be dependent on mysterious chips and software written by others.
I really liked the way Todd acknowedged the tremendous contributions of Wes, and Roy, and Rick and others.
Of course, all of Todd's recommendations are right on the mark. I have been following most of them (but I do fall short and occassionally use a Manhattan pad or two). Todd even gets into the mysterious and arcane practice of boiling (three times!) toroidal transformers. I do have a preference for air-core coils, but that boiling sounds like fun.
One thing that Todd and Brad might also want to consider: tuning linearity. Too often LC VFOs end up having the frequency spacing very close at one end of the dial and very broad at the other end. "Bob's Electron Bunker" provides some great tools for alleviating this problem:
Thanks again Todd!
Posts
Nice Video! Clever way of logging frequency drift, too. Efforts like this help us eliminate unstable components and achieve better warm-up stability.
ReplyDeleteA tightly scripted and edited video way beyond the norm. It includes several uncommon VFO stability techniques that seem to be very effective. However, it would be nice to have a photo of the final as-built circuit board so we can see layout and component mounting, especially regarding rigidity. Hopefully Brad will send a photo to Soldersmoke.
ReplyDeleteThanks Bill - Best! Todd
ReplyDeleteVery good video! Incredibly low drift results by careful selection of components. I was going to rework a previous project that has a Vacker VFO configuration to get better drift results, will definitely use his design guidelines.
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