Yes you can spray radio signals all over the galaxy to improve your chances of hitting
a viable target, but most such signals will be relatively weak. You need to direct the
radio beam at potential targets to have a chance almost as much as Optical SETI.

This is why an ETI is going to have a hard time picking up most of our electromagnetic
signals that we spray into the Universe every day as they are not directed and are
often weak beyond a certain point in space. Same for us regarding any ETI doing the
same with broadcasts in their society. If they have cable and fiber optics, things are
going to get rather quiet at both ends.