Please read the description/textbox first. This textbox/description will belong to 2 video’s that I will upload today, 27 april 2022.
Both video’s regard the use of a pancake coil with a few taps to be used as an oscillator coil, here in the 50 KC-1.5 MC range (the aim). The lowest frequency is easily reached with this setup, because the Q of the pancake coil is very high.
Though in these 2 video’s that highest frequency is not reached, though it (1.5 MC or higher) surely can be reached with this setup and the schematic showed afterwards in this textbox.
Say with less turns of the coil or with a smaller value of the tuning capacitor. |Its minimum value is now (with the showed setup) approx. 70 pF, that is quite (too) high to get to say 1.5 MC or higher frequencies with this coil, the way it was made. Say the lowest inductance still too high, given that 70 pF parallel capacitor.
Less turns in such a “pancake setup” can/will surely help/work, also a smaller tuning capacitor value that bridges the coil, say in the range of 10 pF – 150 pF. Thus: test & try.
About this first test of the pancake coil, showed in this/these video (s): it is connected to a
“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.
Relevant video’s about this oscillator circuit
FIRST BASIC SCHEMATIC 3 October 2015: (part zero)
50 KC- 9 MC or higher: https://youtu.be/Ng49kGF3n8o
Part 1 on 20 April 2022, link
https://youtu.be/iozgTDLEK4s
part 2 on 27 April 2022, link
https://youtu.be/NF_SGON66AQ
part 3 on 27 April 2022, link
https://youtu.be/NkZDrniefho
Next experiments will be to make that universal FET test oscillator with a less obsolete FET, say not the BF 245 A,B,or C, but with a BF 256 A.
But after all: many HF N-FETS (!) can be used here, thus experiment & test & try. More in video’s to come.
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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 27 April 2022.