The AN/PRR-9, AN/PRT-4 squad radio was evaluated by the Army Concept Team in Vietnam, in conjunction with other agencies, to determine its suitability for use in Vietnam. The evaluation was conducted in three different parts: determination of suitability for use by Vietnamese forces; determination of suitability for use by US Army forces; and determination of the impact of the squad radio on the frequency spectrum in Vietnam. Vietnamese tests indicated that the squad radio is as suitable for their use as it is for US forces, and intelligibility probably is better. Communication range decreased significantly when the squad radio was operated in dense jungle. US Army personnel generally found the squad radio to be highly satisfactory but recommended better waterproofing and battery protection. Operational tests and studies by OCCE indicated that the squad radio will not have a serious impact on the frequency spectrum in Vietnam.

The PRT-4 - PRR-9 Squad Radio was used by at least 3 members of a team for inter-team communication.