"Zenith" wrote in message
...

[snip]

I
hooked up several external antennas and reception never improved.

[snip]

A typical ferrite bar antenna is tuned. The radio uses the ferrite bar
antenna as part of the tuned circuit for front end selectivity in the AM
band. Damage to the connections to the antenna will not only reduce signal
transfer but also reduce selectivity.

I can't tell you exactly where your radio's problem is. But I've fixed this
problem on different radios, and it was broken connections at the ferrite
bar antenna.

Frank Dresser