Category Archives: Hartley

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

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

Posted in direct conversion, Hartley, Mrad-40, VFO stability | 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

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

Posted in EMRFD, Hartley, 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

Posted in Hartley, magic receiver, oscillator, VFO stability | Leave a comment

New project underway: the magic receiver

This was a great weekend for building and tinkering.  I feel like I learned a lot more and just finally had some time to really enjoy the hobby. The playing with the little 1-transistor rig got me to thinking about … Continue reading

Posted in direct conversion, EMRFD, Hartley | Leave a comment