Antenna

[Mark-VA]

Homemade

For measuring detector frequencies.

[ivconic]

Lazy as i am; i am constantly trying to find shortcuts in everything i do.
Winding a coils... HORROR! I so do hate that part!
Even when it comes to only few turns...
So i get better idea.
I guess each one of us can easily obtain used and wasted water inlet valve for washing machine, right?
There is solenoid on it... a coil! What a wonderful coil it is!
Can serve for wide variety of tasks in diy workshop.
You just need to dismantle the valve and pull out the coil itself. Easy task.
The rest of the story is History...

[kt315]

Homemade

For measuring detector frequencies.

for measuring of data of a coil was projected especial tester, simplest in realisation.
also, you can buy https://ru.aliexpress.com/item/-/328...6ac833edLk5Slg
like me. as soon it will arrive i will tell you about.

[kt315]

1/ desolder tank cap from your board
2/ connect it to your coil to TX winding
3/ measure frequency
4/ calculate L if you need
5/ add winding or diminish it to get frequency you want

[Mark-VA]

I had forgot all about the copper in those. Thanks for the reminder.

Lazy as i am; i am constantly trying to find shortcuts in everything i do.
Winding a coils... HORROR! I so do hate that part!
Even when it comes to only few turns...
So i get better idea.
I guess each one of us can easily obtain used and wasted water inlet valve for washing machine, right?
There is solenoid on it... a coil! What a wonderful coil it is!
Can serve for wide variety of tasks in diy workshop.
You just need to dismantle the valve and pull out the coil itself. Easy task.
The rest of the story is History...

[ivconic]

Small notice; vast majority of such modern solenoids are coated with plastic.
If you want to salvage the wire from such coil; it would be tedious and hard labor to remove the coat and not to destroy first several layers of wire at the same time.
Trust me; i tried!
But what i meant is use of the complete coil as it is. Just dismantle the metal parts of valve and the core from coil. It is easy.
Inductance and resistance of such coil is HUGE! As i recall; may vary from 30 to 140mH!
I say; even better!
Perfect as heavy load at most of the lab instruments.
"Sniffs" some signals like hell! (i did lot of radio experiments with it)
In short; just try it and you'll see!

[Hyena]

When I built simple spot welder from old microwave, I was able to disassemble secondary high voltage winding without damage. I measured 400mH (without any core) with about 100ohm, dont remember resistance exactly, but inductance surprised me. I have 3 another MOTs which still wait for its occasion. Mutual series inductance would be enormous. Any ideas?

[ivconic]

When I built simple spot welder from old microwave, I was able to disassemble secondary high voltage winding without damage. I measured 400mH (without any core) with about 100ohm, dont remember resistance exactly, but inductance surprised me. I have 3 another MOTs which still wait for its occasion. Mutual series inductance would be enormous. Any ideas?

Geometry of such inductors is playing very important role here.
Water inlet valve coil is just perfect for lot of various experiments.
Inside the coil, where was the steel core before; you can put easily any other type of core now.
Any common ferrite rod will fit easily. By extracting and extending it through that hole; you can affect&adjust the inductance of coil additionally.
Also mumetal tape can be put inside. That's interesting to do and experiment with!
Not to mention adding serial or parallel capacitance with it.
...
With coil that you are taking from microwave oven; i guess you can also make useful coupling with oscilloscope for various measurements.