Multi purpose 1 or 2 MC - 6 MC Sine wave radio oscillator with N-FET BF 256 A, demo & schematic



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Video about a FET radio oscillator (read: a VFO) that (surely) can work between (say) 2 MC and (say ) 7 MC with the use of only one FET, the BF 256 A. Schematic & demo in the video.

With a tuning capacitor (150 pF for SW and 500 pF for MW) that bridges the coil (s) you can tune to very precise radio frequencies on Shortwave/MW. With higher inductive coils: surely on lower frequencies, say in the 1 MC band. For MW often a ferrite rod is used (indicated: 80-100 windings) to get more inductance, ranging to 800 KC-1.6 MC with a paralleled tuning cap. of 10 pF-500 pF.

Test & try & find your way & elaborate. I am always interested in your experimental results, give the links and I will re-publish them when I am convinced that your circuit works in reality, sometimes I will test/reproduce your circuit(s) first before giving such a link.

When my now published circuit does not want to work: change the values of the capacitors in the capacitive voltage divider, now 1N (= 1000 pF) and 150 pF. Especially experiment with the 150 pF capacitor value, take it lower/higher, say to the 200 pF- 470 pF range.

The coil in the source is lead of the FET (field effect transistor, here the BF 256 A) is now 820 uH (=820 Micro Henry). You can make that (read: a working) coil yourself by making 300 windings to 400 windings of “ape” hair copper wire (very thin insulated wire) on a form of plastic, no ferrite or iron core inside, that core with a diameter of 3-4 mm, length 1 cm - 2 cm. Wound on that form the (say) 300-400 windings of that “ape hair diameter” isolated copper wire.

I did not demonstrate the (parralled to the coil) tuning capacitor (can be between 50 pF and 500 pF). With that tuning capacitor you can vary the frequency in an analog way, while the oscillator works, say making the circuit to tune to a specific frequency on SW or wherever.

By the way: when you want to make a simple SW Radio with good properties and use this as a local oscillator (read: VFO): go to the LULU website, where I have published my books and buy this book: “2-10 Shortwave receiver and 1 transistor VFO’s”. Published on the LULU website, October 2021.

I am shadow banned and censored by YT/Google, because I was critical about the mRNA jabs regarding Covid. My critical comments were deleted immediately by Google/You Tube. And when I posted critical comments about the mRNA jabs I only could see them when I logged in to You Tube, so they were not visible for a broad public. They were immediately deleted or only visible to myself when I logged in or only visible on specific YT Channels (!).

That is a mean (=false/low) way of censorship and shadow banning. A shame, You Tube & Google!

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 12 December 2022.
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