- Electromagnetic waves in free space travel at the speed of light
- In transmission lines the speed of the wave is slowed down by a factor K called the velocity factor of the line
- A half wave in free space is:
- 150÷ƒ , where ƒ is in MHz, result is in meters
- (492÷ƒ result in feet)
- A half wave transmission line length in meters is the free space value × K, where K (the velocity factor) is always less than 1 and depends on the type of cable used