no problem jack. if it is random tx, probably a mic. do what sonwatcher says. or if you know someone that has an icom see if you can try there mic on it. the ic-2100h will use several mics. here is a list straight from the owners manual. hm-77, hm-77a, hm-78, hm-96, hm-118, hm-79, hm-97, hm-95...