Things You'll Need
Instructions
Divide the output impedence measurement by the input impedence measurement and write this value down. For example, if you wish to create a balun that matches a 75-ohm input to a 300-ohm output, the number you would record is 4, which is equal to 300 ohms/75 ohms.
Calculate the square root of the number recorded in Step 1. The calculated square root is the turns ratio that the balun must have for maximum power transfer. For the example above, the turns ratio is 2 (equal to the square root of 4).
Convert the calculated square root into a fraction; this fraction will serve as the primary-to-secondary turns ratio of the balun transformer. For the example above, the primary must have twice as many wire turns around the transformer core as does the secondary.