One who dies for a noble cause is called a martyr. He is a person who dies fighting for what they believe in like advocating religious or other beliefs, refusing to renounce, etc...
The hertz (Hz) is defined as one cycle per second and is a SI unit of frequency. Here kilohertz is also a unit of frequency of waves and is defined as 1000 cycles per second. Radio waves are measured in kilohertz (KHz).