Re: DAYLIGHT RADIO - PLASTIC TOROID MASTER
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David, I did a bit of experimental work on this. The toroids need more than 15 turns or so for the self-shielding to work well. At fewer turns, the shielding though better than that of a conventional inductor, wasn't good enough to be used in a bandpass filter. In the Daylight radio, I had to add shielding between the three sections. - f
Yes, understood.? Just thought I would let it be known that it is
not the core that shields a toroid.? It is inherent in its shape.?
Physics.? :-)
On 8/16/22 9:49 AM, Ashhar Farhan via
wrote:
David,
Shielding is not the issue. Losses are. Lower Q
leads to higher losses. The Q is determined by the material
inside the toroid. Air/Vacuum is the best material with least
losses for an inductor, whether a solenoid or a toroid.
Toriodal inductors are inherently shielded by their
geometry, no matter what the core material is, air, ferrite
or other.
73,
David N1HAC
On 8/15/22 8:24 PM, Ashhar Farhan via
wrote:
David,
The inside of the toroid should be
hollow and it not hollow it should have as little
in-fill as possible. This is the key to high
performance 3D printed toroids. PLA or ABS are lossy
and they can lead to lossy filters.
- f
would not a simple tubing do the same?? .. the
"shielding" of a coil wound on a ferrite core
comes from the core material ... so i guess a
normal pastic tubing will work equally well if not
better (fewer loss cause fewer plastic inside the
coil)
so ... what is the reason to print plastic
toroids??
dg9bfc sigi
Am 15.08.2022 um 23:50 schrieb David R. Hassall
WA5DJJ:
Dear group,
I asked a friend of mine to build a master
toroid stl file that we can put in our 3D
printer software and come up with the plastic
toroids almost any size we want.?? The Master
was built on the basic size of 1 inch in
diameter with a height of 1/2 inch and a
thickness of? 0.2 inches.?? I use the CURA
program to build my 3D printer files and it will
allow me to scale all three axes once the basic
25mm toroid.stl file is loaded into the
software.? It also allows you to print almost
any number of a basic design in one printing.??
Here are some examples that I printed this
morning:
![toroid pic]()
I just used the scaling values of 25%, 50%, 75%
and 100% to get the different sized plastic
toroids pictured above.? So with the master stl
file anyone with a 3D printer should be able to
print almost any size plastic toroid form that
you would need.?? I have attached the master stl
file to this Message and it should enable anyone
with a 3D printer to make the plastic Toroids
that they need for the Daylight Radio Project.
Take care and have fun.
73 Dave WA5DJJ
SUPER QRSS GRABBER
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