Please read the description/textbox first. When you want a direct good result with this pancake coil (and its taps, via a rotary switch or a few standard audio switches) make the circuit that is showed in the following video/link:
“Universal FET test oscillator 50 KC - 10 MC or even 11 MC”: https://youtu.be/Ng49kGF3n8o
Schematic, demo, everything is there. It uses, by the way, a buffer stage after the FET.
That oscillator (and the one that I am working on, trying to make it with an not obsolete Field Effect Transistor, thus the BF 256 A, same pin connections) can be used as a simple good quality sine wave function generator, a simple sine wave test VFO, a test-Local oscillator for radio experiments, etc.
Perhaps with 2 anti paralleled diodes at its output another waveform (more square wave like) can be realized? Only an idea, not tested, by the way...
So when you want direct results: in that case, skip this video and let it be.
Of course when you want to watch this video from the beginning to the end, no problem.
I am working on a small sine wave radio oscillator, with more or less the same setup, but now to be used with this pancake coil, that works from 50 KC-2 MC.
By the way: with that pancake “setup” I am sure you can get to 10 MC, say with smaller ”pancake” coils, not many windings, say on a 3 cm disk with a few “fins”. Take the number of “fins” un-even (odd) to get a constancy in braiding the pancake coil.
Feel free to experiment, the FET oscillator (earlier link) is eager to oscillate, though with coils that have a good Q (quality factor). The pancake coil has by itself (by its construction) a quite high Q. So a reason for experiments and much fun/study.
When you have questions about (certain analog) electronic circuits and how to make them: go to my Channel trailer (Radiofun232 on You Tube) and go to the “looking glass”. Type there the keywords that you want/need like: “power supply”, audio amplifier, capacitor tester, oscillator, radio, shortwave, shortwave radio, or any keyword you like to find the essential info & schematics on my YT channel.
You can contact me via email when you have questions about my published circuits. I always ask for a picture of what you have made + a problem description; I ask to communicate.
My You Tube channel trailer is here: https://youtu.be/xbgQ8T3oqh4 When you search, search always “NEWEST FIRST” to get the right overview. You can also search via the “looking glass” on my Channel trailer via keywords like ”audio”, “radio”, “amplifier”, “filter”, “Shortwave”, “transistor”, “FET”, “oscillator”, “generator”, “switch”, “schmitt trigger” etc; so the electronic subject you are interested in. My books about electronics & analog radio technology are available via the website of "LULU”, search for author “Ko Tilman” there.
https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=Ko+Tilman
I keep all my YT videos constant actual, so the original video’s with the most recent information are always on YouTube. Search there, and avoid my circuits that are republished, re-arranged, re-edited on other websites, giving not probable re-wiring, etc. Some persons try to find gold via my circuits. I take distance from all these fake claims. I cannot help that these things happen. Upload 20 April 2022.