usually located in the base operations radio transmitter room. Base electronics personnel perform maintenance on the equipment. The amplifier within the weather office is left in the "on" position whenever the station is open. Pilots do not routinely monitor the transmission frequency, but rather turn to the frequency only when they wish to talk to a forecaster or an observer. The only way the weather forecaster can initiate contact with an aircraft is to have the Air Traffic Controller direct the aircraft to tune to the METRO frequency and contact the office. This, however, is rarely done. When talking to aircraft on the PMSV radio, proper military radio protocol must be used at all times. You must use prowords when applicable. Prowords are pronounceable  words  or  phrases  that  have  been assigned specific meanings in order to expedite voice message traffic. No personal conversation or general chitchat  is  permitted. Proper  radio  procedures  are discussed   in   detail   in   Allied   Communication Publication (ACP) 125, Communiculion Instructions Radiotelephone Procedures. The following guidelines summarize  some  of  the  important  information  provided in   ACP   125.   YOU   SHOULD   AVOID   THE FOLLOWING: YOU SHOULD ALWAYS DO THE FOLLOW- ING: Unnecessary  transmissions Identification of unit locations Use of profane, indecent, or obscene language Transmitting   when   loud   background conversations or noise-levels are present Depressing the transmit button before you are ready to talk, or holding the transmitter button after you have finished talking Misuse  of  call  signs Unofficial  conversations Excessive repetition of prowords Use of plain language in place of applicable prowords Speak  clearly,  slowly,  and  distinctly,  in  a normal,  yet  strong  voice Avoid  extremes  in  vocal  pitch Send traffic in phrases rather than word by word Hold the mike 2 to 4 inches from your mouth Say individual digits, not the combined number Table  1-4  contains  prowords  frequently  used  in PMSV  conversations  and  their  meanings.  Use  these prowords  as  necessary. Your station’s call sign is your airfield’s name followed by the word  METRO.  NAS Pensacola, for example, is Sherman Field, so the PMSV station’s radio call sign is Sherman METRO. When contacting a PMSV station, an aircraft will first provide the aircraft’s call sign, and then the PMSV station’s call sign. For example, "NAVY ALFA GOLF ONE ONE ZERO, SHERMAN METRO." Your reply should  be,  "THIS  IS  SHERMAN  METRO,  GO AHEAD NAVY ALFA GOLF ONE ONE ZERO, OVER."  From  this  point  on  until  the  end  of  the conversation, it is not necessary to repeat your call sign or the aircraft’s call sign unless several aircraft are calling or standing by on the frequency at the same time. Take the aircraft’s request for information or the information passed. Use the word OVER at the end of each transmission to the aircraft, and then release the mike key. Do not depress the mike key again until the aircraft has finished talking and given you control of the mike  by  the  keyword  OVER.  Use  the  phonetic pronunciation for each digit in a number, such as "WIND  THREE-THREE-ZERO  DEGREES,"  instead of,  "WIND  THREE-HUNDRED  THIRTY DEGREES." When an aircraft asks for information that is not immediately available, reply "ROGER, WAIT, OUT." Obtain the information, recontact the aircraft by stating your call sign, and then the aircraft’s call sign, such as "SHERMAN METRO, NAVY ALFA GOLF ONE ONE ZERO." Pass the information only after the aircraft  has  responded. Do not pass weather observation or forecast data by reading the code form. Rather, convert the observation report or forecast to understandable English. You may be  brief  by  prefixing  the  values  with  an  identifying word, such as sky, ceiling, wind, or altimeter. In some cases, you may use common abbreviated words to identify   information,   such   as   temp,   instead   of temperature;   dew   point,   instead   of   dew-point temperature; PA, instead of pressure altitude; or DA, instead of density altitude. If you find it is necessary to spell out long sections of  a  narrative,  use  the  following  words  for  the punctuation markings: comma (,), period (.), paren ( ( ), 1-26