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[W1ITT]

One thing to keep in mind when you are searching for rf noise and shutting off the breakers at the power entrance is your UPS computer supply.  Mine feeds, among other things, a small power supply for a modem.  And, of course, the UPS keeps it alive even when the power is supposedly "off".  Noisy little bugger, it was, and not immediately obvious.

[PA1ZP]

Hi

You have found out that there is a cause of interference in your house.
Try to find that first.
Then the common mode chokes, it is wrong to think that a common mode choke of an FT240-31 with as many RG6 windings as possible will be perfect on 80 and 40.

For the right common mode choke look at G3TXQ site:
http://www.karinya.net/g3txq/chokes/

It can be a great help good common mode chokes, it might help nothing at all.
If the noise is picked up by your antenna, the choke will not help.

I have build HalfWave End Fed antennas that didn't have any issue with common modes, they had ofcourse a good common mode choke.
And i have had balanced loops that did have terrible noise problems, the situation is very depending on your local surcomstances and way of placement of the antenna.

73 Jos

[W4CBR]

The noise on your cable coax is probably a nearby neighbor with a bad power supply in their tv polluting the whole chain. I've seen the extreme of this to where it was affecting my tv signal whenever theirs was turned on. Neighbor things usually do not end well. Apparently I didn't know what I was talking about so unfortunately we did not remain friends. Good luck!

[KX4OM]

I have a Windom antenna up about 40 feet.  I'm seeing noise on my S meter that is running at S9 or higher on 40 and 80 meters.  Nothing on 10, 15.  Some on 20.

Is this normal, or is there some piece of equipment hashing my reception?

Thanks
N1AUP

My setup: Rigs in the basement (IC-7200 and several boatanchors) and 40m dipole at 40 feet. The IC-7200 typically showed S7 to S9 on 40m depending on atmospheric conditions. A couple of months ago, I replaced all of the 15 year old wall dimmer-switches on the main level and the 2nd level of the house with new Leviton Decora DSL06 dimmers with built-in radio/TVI filtering . The lighting is a mix of LED, compact fluorescent and incandescent. The noise has  dropped to S5 to S7 on the IC-7200.

With the old switches, flipping circuit the breakers off on the lighting circuits noticeably reduced the noise level. That is when I decided to replace all of the dimmer-switches. The breaker panel is in the basement about 10 feet from the radios.

Ted, KX4OM

[N8YX]

Grow lights will also cause this, per other threads on Eham.

I had 10/S-9 noise levels on 40-30-20M much of last year, starting at 8AM and ending at 8PM. The noise mysteriously disappeared...probably due to Dopey McDoperson getting his illicit natural pharmaceutical production operations shut down by law enforcement.

Saved me the trouble of localization.

[KA2FIR]

Is your receive preamp on?