Category Archives: VFO stability

Final VFO design for the MRad-40

First, if you haven’t already, please check yesterday’s posting about your favorite QRP/homebrew radio resources and leave a comment!  I got great comments already from Steve VE7SL but I KNOW many more people have read the blog since then!  Please … Continue reading

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Is 1 Hz/hour good stability? :)

I’ve recorded and plotted data on thermal stability for versions 3 and 4 of my Hartley oscillator.  Below is what I got: V3.0 was the well known basic JFET Hartley circuit from EMRFD (as mentioned before) using a 50-6 toroid … Continue reading

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Progress with stability

I spent more time this weekend refining stability for my LC oscillator. Exchanging the wide spaced air variable for a narrow spaced one helped a lot.  I cut my drift rate vs. temperature in half.  I hope to post a … Continue reading

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Oscillator thermal drift (before vs. after mods)

My version 2.o of the MR radio’s future oscillator is shown above.  I gutted all the extraneous LM386 and NE602 circuitry out of the box so that I could just focus on VFO stability. The box is the original enclosure … Continue reading

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Some exciting progress

I’ll post more details soon.  But last night I had some great progress towards rebuilding my little simple receiver, dubbed the Magic Receiver (I’ll just call it the “MR”). The MR was in really sad shape!  I traced out the … Continue reading

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VFO stability quest begins

“VFO building is an art form as arcane as Grandma’s secret pie crust recipe or the fine points of building Cub Scout Pinewood Derby racers.” — Frank Harris from “Crystal Sets to Sideband”, 2010. I began my quest in earnest … Continue reading

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