In article .com,
Ancient_Hacker wrote:

In 1975 when I moved my bussiness to a building a quarter mile from an
AM station we could hear it on the phone. The phone co. sent out people
two times and put various filters on the line all to no avail. Finally
on the third visit an old timer who looked about to retire came in, put
a small mylar type cap across the ear end terminals in the handset. No
more problem, not ever on other extensions when they were put in.

Chuck P.