 
 <prompt> How power ratios dey measure? Given di last question, write one context wey contain di answer. E fit be 1 - 20 sentences. Context: <response>: As electro-magnetic wave dey waka through different parts of antenna system (radio, feed line, antenna, free space) e fit jam differences for impedance (E/H, V/I, etc.). For each interface, based on the impedance match, some part of the wave energy go reflect back to the source, forming standing wave for the feed line. The ratio of maximum power to minimum power for the wave fit be measured and e dey called standing wave ratio (SWR). SWR of 1:1 na ideal. SWR of 1.5:1 dey okay small for low power applications where power loss dey important, even though SWR as high as 6:1 fit still work with correct equipment. To reduce SWR and make power transfer pass through each part of antenna system, e dey important to minimize impedance differences for each interface (impedance matching). 