A simulcast controller 201 receives a communication request at a current time. A preliminary launch time equivalent to the sum of the current time plus a predetermined offset value (401) is calculated along with a difference between the preliminary launch time and a transmission conclusion time (402). When the difference is not greater than a sum of a predetermined dekey interval (404) and a predetermined keyup interval (408), a supplemental offset value (406-407) is added to the preliminary launch time to produce the initial launch time. Alternatively, upon termination of a previous communication (600), a period of time equivalent to the sum of the predetermined dekey interval (602) and the predetermined keyup interval (603) is initiated. If the current time is earlier than an expiration time (604), the predetermined offset value (601) and the supplemental offset value (606-607) are added to the current time to produce the initial launch time.