Car radios have good AM reception

摘要

I was interested to see the Mini Entertainment Unit project in the February edition. I live 100km northeast of Perth in a house that is comprehensively RF shielded. It is steel-framed with foil 'sarking' in all the walls, foil-lined insulation under the floor, foil-lined 'air-cell' lining under the roof and a corrugated metal roof. While the window apertures allow some FM reception, AM is impossible. Being aware of the fact that reception was good in car radios, I bought a cheap one from JB Hi-Fi. In this case, I wired it to the speakers in an old defunct cassette/radio. I ran an extended antenna lead through the wall via a wall-plate and up to a car radio antenna mounted on the verandah roof. The radio is powered by a 12V 1A regulated plugpack.