 
 <prompt> How dem dey measure di wave? Given di last question, write one context wey contain di answer. E fit be 1 - 20 sentences. Context: <response>: For example, for 30 MHz (10 m wavelength) if true resonant 1⁄4-wavelength monopole go dey almost 2.5 meters long, and if you use antenna wey only 1.5 meters tall, you go need to add loading coil. Dem fit talk say the coil don lengthen the antenna to achieve electrical length of 2.5 meters. But the resistive impedance wey go come out go dey lower pass the impedance of resonant monopole, e fit need more impedance matching. Apart from lower radiation resistance, the reactance go dey higher as the antenna size dey reduce, and the resonant circuit wey the antenna and tuning coil form go get Q factor wey go rise and fit cause the bandwidth of the antenna to no dey enough for the signal wey dey transmit. Na this thing dey make the size of antennas dey set at 1 MHz and lower frequencies. 