A technical question about attenuating QRM

[Golay]

I've been having this brain fart lately so hear me out.
Hanging a low pass filter across incoming power lines, or plugging a low pass filter into an outlet. Maybe even a low pass filter across the antenna leads.
You get the idea. Taking everything below a certain frequency to ground.

Just a thought I've been having. Not saying I would go thru the motions of trying it myself.
But theoretically do you think doing such a thing may attenuate QRM?

 

[k7ng]

There are various filters purpose-designed for filtering power lines.
If you are meaning putting a RF LPF across power lines, well, you might want to make sure your insurance is paid up.

 

[K3YGX]

I believe you mean QRN

 

[KD8DVR]

There are various filters purpose-designed for filtering power lines.
If you are meaning putting a RF LPF across power lines, well, you might want to make sure your insurance is paid up.

Life insurance.

 

[Golay]

I believe you mean QRN

Yeah maybe.
My understanding is QRM is man made interference. Electrical power lines, consumer electronics, etc.
QRN is natural made interference, such as lightening strikes, etc.

 

[AK9R]

My understanding is QRM is man made interference.

Man-made as in some person is transmitting a signal that is interfering with you.

QRN is natural made interference, such as lightening strikes, etc.

Generally any form of static, lightning or otherwise.

 

[dlwtrunked]

Man-made as in some person is transmitting a signal that is interfering with you.


Generally any form of static, lightning or otherwise.

"Man-made as in some person is transmitting a signal that is interfering with you."
But to include interference from electronical/electronic devices and often these are what is meant with "some person transmitting" often called by many (not all) just "interference" rather than QRM. ("transmitting" must be taking in the broadest definition.)

 

[prcguy]

If the interference is on the frequency you are using a filter in the antenna or feedline won't help as it would reduce or eliminate reception of that frequency. For broad band noise from power lines, etc, its best to remove the noise at the source by filtering the noise maker or replacing it with something that doesn't make noise.

In some cases the noise is made in your own house where you have control over it and if you can find the noise maker you can deal with it. Sometimes the noise can come from computers or equipment in the house and get induced onto the shield of your coax where it travels up to the antenna and gets received. In that case a good ferrite choke at the antenna and/or where the coax exits the building can strip off the noise so it doesn't make it to the antenna. The results of that can be noticeable but not drastic.