Category Archives: oscillator

Oscillator honesty from ARRL; buffer and amp – dead JFETs

Let’s make the embarrassing confession right here at the beginning: Very few oscillators you see in published circuits or commercial equipment were designed by the equipment’s designer.  Almost all have been “Borrowed,” “Re-used” or just plain stolen.  While recycling in … Continue reading

Posted in amplifier, ARRL Handbook, buffer, Hartley, Mrad-40, oscillator | Leave a comment

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

Posted in EMRFD, Hartley, oscillator, VFO stability | Leave a comment

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

Posted in EMRFD, Frank Harris, oscillator, VFO stability | Leave a comment

Good old cut n’ try empirical

I seem to have drifted away from paper and pencil and LTSpice design and back into the old style cut and try methods which I used in high school.  If one thing doesn’t work, try another.  I think sometimes it’s … Continue reading

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Colpitts stuff bookmarked, onward to mixing

I’ve decided that I’ll have to return to the Colpitts stuff later.  It seems to me that a lot of the small signal AC analysis nomenclature and procedures are applied to understanding this circuit, and I’m just not refreshed on … Continue reading

Posted in mixer, oscillator, Philco | Leave a comment