CHAPTER 5 COMMUNICATIONS SYSTEMS
Section I. General
5-1 General. The communications system consists of three separate communication methods. These include radio
communications equipment, foghorn, and intercom telephones, which are briefly described as follows. Details are in
Section II thru Section IV.
5-1.1 Radio communications equipment. Barge radio communications equipment is located in the dayroom and
consists of a type AN/VRC- 46 High Frequency (HF) Frequency Modulation (FM) Army issue radio (hereafter the HF/FM
Army radio), a Very High Frequency/Frequency Modulation (VHF/FM) commercial marine radio, and Ultra High Frequency
(UHF) FM handheld walkie-talkie transceivers.
5-1.1.1 Army radio. The HF/FM Army radio provides communications with other stations equipped with radio
frequencies reserved for military (primarily US Army) use. This radio enables the barge to communicate with its towing
vessel, other military support vessels, military shore-based radio stations, and aircraft. Transmission distance is normally
25 miles or less.
5-1.1.2 Commercial marine radios. These provide VHF/FM radio communications between workboat and barge and
between workboat or barge and other vessels equipped with radios working these same channel frequencies.
Transmission distance is normally 25 miles or less.
5-1.1.3 Walkie-talkies. These preset, crystal-controlled, handheld, nickel cadmium (ni-cad), battery-powered, portable
radios can be set to the same frequencies available on the commercial marine radio channels and provide VHF/FM
communications between crew personnel onboard, between shore and crew personnel, and between crew personnel on
workboat and barge. Transmission distance is normally 5 miles or less.
Under US Federal Communications Commission (FCC) regulations, commercial
marine ship radio and walkie-talkie stations, operating In US and adjacent waters,
are primarily reserved for safety of life and property. Therefore, distress and
safety communications have absolute priority. Those frequencies not reserved for
calling, distress, or other safety purposes, however, may be used for radio
telephone calls to coast stations or between ships.
Operation of radios using military frequencies Is controlled by Army Standard
Signal Instructions (SSI) and Signal Operating Instructions (SOI). Extracts of
necessary portions of these documents are obtained from the Army unit to which
the barge Is attached or assigned.
5-1.2 Foghorn equipment. This equipment sounds the foghorn to warn oncoming vessels of barge location during poor
5-1.3 Telephone system. This system provides intercommunications between dayroom system operator and
crewmembers at any telephone station on the barge. Telephone stations provide jack receptacles for connecting a
headset. By using dayroom telephone equipment, operator can page and communicate with personnel at any telephone
station. When on line with operator, crewmembers at telephone stations can communicate with operator or crewmembers
plugged into other stations.
Section II. Radio communications system
5-2 Description. The radio communications system for Water Purification Barges 300-WPB-XXX includes a US Army
tactical radio AN/VRC-46, two commercial marine radios, and three walkie-talkies. Each is designed to provide radio
communications with stations equipped with similar type radios operating on matching frequencies. This system, shown
in Figure 5-1, consists of the major components listed in Table 5-1. Individual radio equipment is shown in Figures 5-2
thru 5-5. Equipment specifications, maintenance information, and manufacturers' service manuals are contained in