The modern home is a cesspool of RF Noise. Imagine if you will for just a moment, a visualization of your home as a wire frame model surrounding your amateur station. Now mentally picture all of your house wiring, network cabling, security systems and ancillary wiring like doorbells etc. in that wire frame visualization of your home. After visualizing this now attach, to all the pictured wires, a set of devices that are the moral equivalent of high powered RF generators. Yes, that DVR and HDTV are signal sources-really high powered signal sources. To make matters worse, they are connected to all of those wires that you visualized just a moment ago.You see the noise sources travel around in your home unimpeded by light switches and other disconnects. Neutral is not switched. Ground (safety ground) is not switched. They are wonderful and continuous antennas. Now add all the other kinds of devices that make noise; toothbrush bases, battery chargers, water bed heaters, garbage disposals, paper shredders and almost anything else connected to your homes antenna systems (house wiring). In actual fact your radio is surrounded by a closed wall of RFI just as dense as your connected electronics and appliances can make it. All of this running 24X7.
Improving receive environment is a two stage process. First eliminate your noise from traveling up to the antenna via common mode and converting to transmission mode at the feedpoint thus raising your received noise levels. Second quiet each internal home source one by one. The simplest means to finding noisy devices is to use a small shortwave receiver and a B Field Receiving loop. I will attach a crude diagram of one here. It is the best and most inexpensive way I have ever heard of of finding noise. My transistor receiver was bought as an open box special at Fry’s electronics. They are available almost everywhere. Detection is done on shortwave bands in AM Mode. A simple task for almost any small transistor shortwave receiver.
Thanks for reading my blog. Best, Chas W5PG