Please read the description/textbox first. Second video about the dipmeter & test oscillator, working between 20MC and 110 MC. Much more info in the description.
Correction to the video: on 9.18 I say “switch the freq. analyzer out” but of course I mean: “switch the test oscillator/dipmeter out”.
IMPORTANT: both the BIAS potentiometer and the SENSITIVITY POTENTIOMETER influence EACH OTHER when you want to get a coil into oscillation. Take care of that effect.
And: The very sensitive capacitor tester (5 pF- 100 pF and much more all non polar caps) is in this video https://youtu.be/etEfoHZAmww
And (sorry) there were police sirens on the background, that is/was why I was somewhat hesitating in the video and say somewhere "now they are gone". You can hear them with a headphone on.
Earlier videos are here:
Important (dipmeter basics) : https://youtu.be/Reu72iLq034
Less important (only the oscillator, anyway): https://youtu.be/SUXYCphn2E
The test oscillator/dipmeter that is showed here in the video works with different (experimental or not) coils, just like the circuit published in “dipmeter basics”. Link above.
Now it was (again) tested with a coil (watch the video) of (say) 6-7 windings massive copper wire, 2 mm diameter, wound on/via a form of 7.3 mm diameter (the shaft of a drill), open air coil, working in the approx. 107 MC band.
With all the harmonics, by the way, it is/was giving out much/many higher HF frequencies (harmonics, read the textbox & watch the video).
But when you make (say) 20 windings of 0,4 mm wire combined with the tuning capacitor that is inside this test-oscillator (10-50 pF paralleled), you can go to 20-30 MC or so.
With -of course- all the second and more harmonics generated via 30 MC, say 2 x 30 MC = 60 MC, 3 x 30 MC = 90 MC and so on. Visible on the spectrum analyzer. Even harmonics, by the way.
To show the properties of this test oscillator/dipmeter I used a spectrum analyzer, the so called ”Tiny Spectrum Analyzer”. The tiny SA, you can Google it.
You can buy it via Ali Express, but be aware of the fact that there are “clones” of this Tiny SA on the www.
And the clones can sometimes not work properly, so do some study or go to the website of the tiny SA for more info. Easy to find via Google and all good & reliable info is there. 25 July 2022.
These clones could be cheaper, but (as far as I could see) they sometimes work different or not good, compared to the original Tiny Spectrum Analyzer, sold via reliable suppliers. Anyway.
The video shows the definitive circuit of the test oscillator (and dip meter) working between 20 MC and 110 MC.
And given the spectrum analysis this mini oscillator working on say 20 MC-110 MC also works on much higher frequencies, via the harmonics that it strays out.
They (these harmonic signals) go into the (say) 200 MC band and also can be used when developing HF (radio) circuits, so in a certain sense this test oscillator/dipper is a basic radio oscillator for HF/VHF/UHF.
So watch the video for the best information you can get on YT when regarding this elementary HF/UHF/VHF circuit that works as a transmitter in these radio bands.
Thus when you want to work and make electronic circuits on HF/VHF/UHF.
This is an instrument that you can use and can help & give insights about what you have made. Easy to make and cheap.
Only issue is: try \to avoid the so called “hand effect” by shielding the circuit in a steel/tin plate box. Be aware of the fact that too much steel plate shielding has an effect on the capacitance value of the tuning capacitor. Thus I did not shield the tuning capacitor (10-50 pF) completely with tin plate. I found that, in that case, the tuning capacitor only worked between 20 P and 50 P instead of 10 P and 50 P. Could make a difference when testing HF coils on their resonance. Anyway.
That is why this dipper/test oscillator circuit is published “as it is” (watch the videos).
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 25 July 2022.