Torroids!

[TheRATT]

Hello, my electromagnetic friends!

I've been reading about Torroids lately as I live in a small apartment and the noise sources are... plentiful.

What I can't figure out is do the torroids go on the the item making the noise, or on the receivers that pick up the noise?

Any other laymen explanations or extra insights would be welcomed!

213

 

[338_MtRushmore]

They work both ways. It will keep rfi from entering , or exiting a device.

 

[nomadradio]

If you wind a wire into a coil it becomes an inductor. If you have enough turns of wire you can get enough inductance to function as a RF choke, and it will oppose the flow of AC current. If the AC current of interest is noise from an electrical appliance, it can serve to suppress RF interference.

If the AC current you want to block is RF that wants to travel on the outside surface of an antenna coax cable, the term "balun" is often applied to this use of a choke. Winding the coax around a 2-liter pop bottle is one way.

A toroid core is made of materials that concentrate a magnetic field. Winding a wire around the toroid gets you a stronger magnetic field from fewer turns of wire. This makes the wire wrapped around the toroid into a RF choke if you use the right toroid core and enough turns of the wire. If that wire is the coax cable leading to an antenna, it makes the outside surface of the coax into a RF choke without disturbing the ability of the coax to carry RF signals on the inside surface of the coax shield.

Pretty sure that's the picture you were asking about.

73

 

[Slowmover]

Both.

As an experiment where some dollars spent may not pan out, thus far they’ve worked for me (mobile; big truck).

IOW, I’ve installed onto transceiver power leads (both ends), and onto truck components.

Where, “all wires/cables are receivers AND transmitters”.

.

 

[BJ radionut]

Lots of info and pictures here:
https://palomar-engineers.com/