A few things about shortwave:
- The time of day matters - more specifically where the night-path
is relative to you and the station you are listening to. Path that
allows shortwave to propagate to the other side of the world is created
by the Sun ionizing the ionosphere - too much and you get noise; too
little and there is no propagation; typically the residual ionization
after daylight allows from best propagation without overwhelming the
signals with turbulence and noise. This means you have to pick the time
when you listen to match the specific station propagation path
necessary; it's not an "always on" thing like the internet.
- Antennas matter. You can get by with small ones; even stock
whips but there will be a lot of stations you will not hear without more
power. Basically you can only receive stations with enough power to be
above the "noise floor" of your receiver - there is no magic that can
recover stations below the noise. Antenna size is directly related to
have much electromagnetic radiation you can convert to energy for your
radio. Bigger net == Smaller signals received.
- Look at program schedules to identify specific signals you want
to try to receive. There is the paper version of the WRTH which is all
broadcast radio on shortwave and then some. There are online resources
as well. One nice feature of this is the broadcasters have often picked
their schedules for best reception is a given target area so you don't
have to calculate the propagation details yourself.
- Have patience. Sometimes signals simply "drop out" or "fade". It's "a feature" of shortwave. Think about the times when shortwave was the only best way to communicate internationally in a timely fashion in many cases (e.g. from the 1930s through the 1960s). Even today intercontinental jet flights to Europe or Asia use shortwave for contacting "civilization".