>as long as possible, and as high as possible. Caveat about 'long as possible' (for general shortwave listening): Once the antenna is over a half wavelength lo

>as long as possible, and as high as possible. Caveat about 'long as possible' (for general shortwave listening): Once the antenna is over a half wavelength long at the operating frequency (10MHz, one wavelength is ~~ 100 feet, 30 meters), it becomes increasingly more directional along its axis. (Longer still, even more directional.) This may dampen the signal amplitude for signals coming in 'off the side' (compared to a dipole at least).