AM radio reception in my house is plagued with interference, buzzing from light dimmers and hum from who knows what. Even my two solid state high efficiency transmitters, one of which is ground mounted outside and capable of 1 mile car radio range, cannot overcome the noise inside the house, but perhaps it is a mistake to think that a strong AM signal is going to overcome electrical noise in a home.
I recently noticed that a 5 kW local station also had noise on a portable receiver in my house but a 5 kW station 70 miles away did not have the usual noise on the same portable in or outside of my house.
Maybe weaker is better since it is known that AM RF can get into things such as wall warts, switching power supplies, and almost anything connected to the AC line. A weaker signal perhaps lacks the strength to cause mixing and hence noise in devices around the house.
So, some experimenting was in order using my Part15 homebrew tube transmitter. The transmitter operates with 67 mW final input power and uses a 3 meter wire antenna strung upward from a shelf and along the ceiling joists in the basement. The range on a portable is about 100 feet so the combination of low final power and the antenna pretty much conspire to produce a pretty puny radiated field strength Despite this, around the inside and the outside of my house the signal is received noise free on the portable. It also provides a noise free signal to line operated AM radios including a 1962 vintage all american five tube receiver.
It seems from this that noise problems can be avoided by using a reduced power and poor antenna for housecasting.
Anyone else have similar experience?