My garmin unit is a 77/200 hz . Like I said it doesn't bother all the time but on occasion it dose. I have a single transducer mounting plate on the boat. Space is limited because of the kicker. When it dose bother I switch freq for awhile and then turn it back to the lower freq. Most days it only happens once or twice. no my garmin is not a chirp unit. The people at fishhawk were very nice and responsive to my questions. Good luck, Matt