d. lower, nigher 12. The of an antenna depends upon the frequency of the RF signal. a. length b. amplification c. power d. tower height 13. Sky waves bounce between the ionosphere and the surface of the earth due to a. Reflection b. Scattering c. Refraction d. Diffraction 14. When using the same antenna for full-duplex communications, you have to use different frequencies for tansmitting and receiving simultaneously. a. True b. False