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Here is a fine tune circuit using four 1N4005 diodes in series as varactors which can be used to help tune stations. It has about 30pF total capacitance. It is very stable and works better than Kitchen's "poor man's varactor" fine tuner. L2 is the main coil. The cap is .01 uF. No matter how many times I try to edit and rotate the image, it still saves it upside down, but hopefully you get the idea. I really hate Google+. I don't know why it can't be as easy to use as Facebook.
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Phase noise of my Collpits oscillator with LC tank (no cristal involved). Leaves room for improvement..
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Pics of my receiver.
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12/27/16
2 Photos - View album

Kostas builds a take on Peter Parker's ceramic resonator single signal regen: http://qrp.gr/regenrxcer/index.htm

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Just as a suggestion, on my Kitchens design, I added a push-pull second audio stage after the LM386. This greatly boosts the audio and makes many more stations worth listening to. I'm running my audio section with 15V. You can see this audio section on the upper right hand corner of the strip-board photo.


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Hello everyone. I would like to mount the MK II sproutie, but I have difficulties getting the toroids for the coils, does anyone have any information on the characteristics of the coil that can be used in place of the toroids? Thank you.

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Had better luck with a Kit than trying to homebrew! Found un-built with all parts for $20 at a Hamfest, and soldered it together. It's neat! Covers about 3.5 Mhz to 11 Mhz. Antenna is just a ~40 length of wire going out a window.

Heard all kinds of things tuning around I had never heard before - lots of broadcast stations, some SSB on what I think was the 80m band, a couple WLO beacons.... what fun!
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Tried putting together my first solid state regen this evening based on the N1TEV design from QST. Not much success, I'm afraid, couldn't seem to get the thing to oscillate, much less almost-but-not-quite-oscillate. Had a lot of fun, though, and looking forward to more experiments!

KK9JEF

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