Complex sentence: A transmatch matches transmitter impedance to feedline impedance, so that signal power from the radio transmitter smoothly transfers into the antenna's feed cable; a properly adjusted transmatch prevents transmitted power from being reflected back into the transmitter (" " backlash"current").
Split into simpler sentences: A transmatch matches transmitter impedance to feedline impedance, so that signal power from the radio transmitter smoothly transfers into the antenna's feed cable. When properly adjusted, a transmatch prevents transmitted power from being reflected back into the transmitter (" " backlash"current").