When I was younger I once tied a wire around the wires of the antenna
bar ( the one with a magnet and wire coil waxed onto the PC board) and
strung it far out about 10 to 15 feet or even more. Once i did that I
started to pick up shortwave frequencies but normal AM frequencies as
well, The only problem was when nightfall came that radio was just
jammed with stations.

That was at least 10 years ago. Last week I wanted to start a project
on a simple portable am-fm radio that I bought from wal-mart ( also
available @ familydollar for the same price) with the pricetag of
$5.00... I unassembled the portable receiver to where I got to both
sides of the circuit board. I noticed that I received Shortwave
signals when I touched the long 15 foot wire to the RED wire which
goes to the antenna bar from the circuit board. This was at night so
it seemed that this part of the circuit picked up the night signals
good. as for the daytime it wasn't so hot. so to deactivate AM ( 530
- 1710 khz) on this little receiver by cutting the waxed copper wire
that attaches from the tuner directly to the anntenna bar so at night
this receiver would only pick up Shortwave signals. The tuner is
really random but the funny thing is that this little receiver is
picking up these Shortwave signals, you can hear scrambled amateur
radio as well but it sounds like the BFO is off so it's just like
noise. has anyone sucessfully coverted a typical Am receiver to
shortwave by modifying it's antenna? This is really cool! This little
sports radio is picking up WYFR at night and some chinese Radio
station that was broadcasting to America in english, and others. Has
anyone tried this?