E Z Peaces wrote in
:

Jeff Wisnia wrote:
The Daring Dufas wrote:


I had a friend some years ago who ran the communications
division of the local power company. This was back when
they had HF radios for communications and the techs actually
had to know something about electronics. They would get
electronic interference complaints which were often traced
to doorbell transformers. It was a very common problem and
one that many people don't even think of today.

TDD


Sorry, but I have a hard time believing that.

If it was "a very common problem", can you offer a cite proving that
a 60 hz transformer and 10-50 feet of unshielded wire with 24 vac on
it can cause interference at radio frequencies?

Wouldn't you expect that if that story was true those big pole pig
transformers and all that higher voltage wiring running on the poles
on nearly every street would have caused the radios to melt? G

Jeff


According to the FCC Interference Handbook, defective doorbell
transformers are often a source of interference to TVs and other
household electronics. It may be a neighbor's transformer. I think
it happens when part of the core comes loose and vibrates.

Interference from a neighbors transformer is rampant in that when people
realize it uses 3 bucks of electricity a year to run they buy a couple
of hundred feet of copper cable and conduit (so it's code compliant) and
illegaly trench it to the neighbors power.