Talking about flat radio or oscillator coils, usable for freq. between 600 KC and VHF intro/demo
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- Опубліковано 12 вер 2024
- Please read the description first.
The subject of this video is only this: talking about making and using flat radio coils.
Such a flat radio coil can be used as a radio receiver antenna coil (many 1920’s and 1950’s radio’s are/were using it) or as an oscillator coil.
It is a (kind of) braided coil (at least here: 200 KC-800 KC…not always…!) on a form of pertinax or properly varnished wood or whatever non-conductive (in electrical terms) material. More info in the video.
No moisture must get into that coil, otherwise it will lose its capacitive/inductive properties.
In VHF and UHF terms: these flat coils are often etched on a pertinax/glass fibre board. Also on (say) 13 MC it can work that way.
Because the inductance and the (stray) capacitance are surely and properly fixed (locked) in that case.
Such an “etched” flat coil on a pertinax or glass fibre board can thus be very stable on its frequency where it was made for in the HF-UHF-VHF-EHF range.
There are/were many oscillators published in that way fort he 88 MC-110 MC band. Say “home transmitters for the FM band” etc.
You can also see that on receivers/transmitter boards made for the 455 MC range, or etched coils (on a board) in Satellite receiver units, thus LNB units.
There is always an etched coil in such an LNB there to receive frequencies in the GHZ range, of course with a length of a (few) centimeter(s) (millimeters) or so (related to the wavelength).
But of course what I show now/here (as a flat coil) works not so high, thus only in the (say) 200 KC-800 KC range. Perhaps on higher frequencies? With properly made flat coils: yes.
And it (this) is not etched but surely (somewhat) flat.
There are (perhaps) calculation modules on the www for flat coils. To calculate coil X for frequency Y.
These could be useful or useless, because with every coil or filter there is an input-output impedance, damping the properties of such a coil, when it is immersed in a transistor or tube circuit. That is radio theory.
Original schematic of what I am showing here is • Radio oscillator 50 KC...
It is about what I called in the past “the pancake coil”. In the description of that video you will find other links to other relevant video’s.
The direct links are here:
Relevant video’s about this oscillator circuit
FIRST BASIC SCHEMATIC 3 October 2015: (part zero) 50 KC- 9 MC or higher: • FET test oscillator si...
Part 1 on 20 April 2022, link • Radio oscillator sine ...
Part 2 on 27 April 2022, link • Radio oscillator 50 KC...
Part 3 on 27 April 2022, link • Radio oscillator 50 KC...
My You Tube channel trailer is here: • Radiofun232 on UA-cam...
Type there (on my YT Channel, via the “looking glass ( = search option) ”the keywords that you like (e.g. radio/audio/amplifiers/test/filter/) in the “looking glass” = search function” and give “enter”. Via that you can find specific video’s (under the say 1500 published).
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. www.lulu.com/s....
I keep all my YT videos constant actual, so the original video’s with the most recent information are always on UA-cam. 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. Upload 8 August 2024.
Thanks for interesting video. I bought a coil like this from a radio rally here in England, recently. I think it came from a radio and it is on a compressed cardboard former with windings made from enamelled copper wire. I know some flat coils were made from Litz wire. Perhaps you could talk about Litz wire in a video some time? I would like to learn more about Litz and this type of coil.
This is a video with general info ua-cam.com/video/B6JOURTyCt8/v-deo.htmlsi=ZQ3sgmaS76SXLC4-
@@radiofun232 Thank-you Ko, I will have a look.
I have some very old National Brand resonators at 456KCs. If these are of interest to you, I will be happy to send you 2 examples for your experiments and videos. Please let me know if you would like them.
@@acestudioscouk-Ace-G0ACE Hi, I appreciate your offer very much, but I have (too) many components, coils, etc. Thanks!
@@radiofun232 Thanks for the reply and I know the problem! I just thought you might be able to make use of them.
I always lean something new when watching your electronic videos. Thanks.
Intresting 😊
Thankyou for sharing, 👍
Looks like the old 1920's spiders web coils, designed to reduce capacitance. G7VFY
sure!
👍 T hank you sir.
Why was the winding alternated around the spokes? Why not just use a flat coil without flipping the thread up and down?
Both is possible. Alternating has an effect on the stray capacitance.
it is out of boredom
@@Sergiu.antifascist Out of boredom? What do/did you mean?
@@radiofun232 people get bored, and when they are too bored, they begin to wind the coils in different manner
this kind of flat coils are not good for oscillators, but can be good for filters.
filters do not need stability. what gets bad stability for generated frequence, is not important for filtering.
oscillators are sensible to vibrations, filtering is not
This is a working circuit, but also a demo of the properties of such a coil. When all is made well (fixed windings, etc) the stability is OK. Of course not "crystal stability", but that is logical when you are somewhat acquainted with radio technology. Could be used as antenna coil & as oscillator coil. Everyone must do his/her experiments, to get good results on frequency "x" when working with this setup. 12 Aug. 2024.
@@radiofun232 beautiful work!