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FM 24-18: Tactical Single-Channel Radio Communications Techniques


I-1. Purpose

The primary job of an operator is to send and receive messages as rapidly and accurately as possible. To perform that job effectively, the operator must also keep a record of messages sent and received and of other important events that happen during his tour of duty. DA Form 4158 (Operator's Number Sheet) is provided for this purpose and includes the circuit log and the operator's number sheet. The operator's number sheet is not normally used for FM radiotelephone nets.

The circuit log portion of DA Form 4158 is used to record opening and closing times, frequencies, frequency checks and frequency changes, traffic delays, and any incidents or conditions affecting circuit efficiency.

The operator's number sheet portion of DA Form 4158 is a record of messages transmitted and received. It tells the operator which number must be assigned to the next message and how many messages have been received.

I-2. Procedures for Filling Out the Circuit Log

In the station-channel-net block, line through the word channel when operating a radio net (fig I-1).

Under station your call sign is printed. The net call sign is printed following your call sign.

The date block is completed by filling in the day, month, and year.

Figure I-1. Station-channel-net block.

The log sheet has three columns. The first is the time column. The hour of the day with zone letter suffix is entered in this column. The following (fig I-2) is an example.

Figure I-2. Time column.

The operator's sign is completed by printing your personal sign. Your personal sign is normally your initials. Figure I-3 shows an example with Kilo Watt as the operator.

Figure I-3. Operator's sign.

The first entry in the remarks column is the operator on duty. To complete this entry, print your rank, name, and the words on duty. An example is shown in figure I-4.

Figure I-4. Remarks column.

In the remarks column, there are mandatory entries that you must make. Here is a list of mandatory entries:

  • All opening and closing transmissions.

  • Identifying portions of all messages sent or received by your station.

  • Causes of delay.

  • Frequency adjustments.

  • Unusual occurrences:

       --Procedure violations.

--Security violations.

--Interference with reception.

Mandatory entries are made as they occur.

The time column is filled in at the beginning of an action and at the end of that action. Refer to the log sheet in figure I-5. A time was entered when the NCS starts to open the net (0702R) and again when the net is open (0708R).

Figure I-5. Complete log sheet.

When recording messages, only identifying portions (message number, precedence, and date-time group, month and year) are normally used. This is controlled by the standing operating procedure of the unit. Example:

Example I-1.

The entries on the log (fig I-5) at 0720R and 0725R indicate a cause of delay.

When an error is made, do not erase. To correct an error, line through the wrong portion and initial after it. Continue with the correct information. The log, figure I-5, shows an error in the entry at 0730R.

The operator must make a closing entry at the end of the day (2400 hours) or when going off duty. The closing entry will be the operator's signature followed by the words OFF DUTY printed. The log, figure I-5, shows a closing entry at 0738R.

A new log will be started at 0001 each day.

I-3. Procedures for Filling Out the Operator's Number Sheet

The operator's number sheet is a record of sent and received messages. It is used to assist in handling, recording, and checking traffic. The number sheet is helpful in assigning station serial numbers. (Station serial numbers are not normally used on FM radiotelephone nets.)

A new number sheet will be started each day at 0001 hours. A list of messages sent and received for each station is recorded. Messages that are recorded on the number sheet are noted by the date-time group of the message, time zone suffix followed by the operator's initials.

Enter call signs and date in blocks. STATION CALL is your call sign.

Figure I-6. Call sign blocks.

NET CALL is the net call sign. OTHER STATIONS CALL will be call signs of other stations in the net. Example is shown in figure I-6.

The columns under other stations call are used to record messages sent or received. Figure I-7 shows an example of sent and received columns.

Figure I-7. Sent/received blocks.

Figure I-8. Completed operator's number sheet.

Procedures for recording traffic are given below.

  • Procedures for recording sent messages:

       --Assign numbers in order of handling.

--Each station will have its own sequence.

--Strike slant sign through number on operator's number sheet in sent column. --Enter date-time group on operator's personal sign.

  • Procedures for recording received messages.

       --Strike slant sign through number sheet, after receipting for
         message, in the receive column.

--Enter date-time group and operator's personal sign.

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