Use the whip antenna fully extended for shortwave. If you are trying to listen to shortwave indoors you may not hear anything depending on your building type. Steel and concrete, brick and aluminum sided buildings do a great job of blocking shortwave signals. Go outdoors or out on a porch for best reception. A few hours around sunset and sunrise are usually best for shortwave reception but daytimes can be good on the higher SW bands.

I haven't used any of the radios you mentioned but I'll hazard a guess that the Eton will be the best shortwave performer. A short, reel-up random wire antenna like this can offer big improvements for inexpensive shortwave portables. This one has a clip to snap onto your whip antenna.

You can try one of these reel-up shortwave antennas. They clip onto the whip antenna if your radio doesn't have an antenna jack. These antennas are usually under 23' in length. You can also buy some hookup wire and solder on an alligator clip. Same thing, but no reel. Keep the length short. Most shortwave portables priced under $100 US will overload with longer antennas. When they overload you will hear a lot of distortion and the same strong stations appearing repeatedly all over the band.