The directions from the late-WWI SCR-68 aircraft radio includes the following
advice, which remains likely valid for radio operators today:


(1) Do not forget to inspect the set before each flight.  

(2) Do not forget to plug in the telephone transmitter and telephone receiver
    plugs.

(3) Do not forget to throw the "Receive-Transmit" switch on "Transmit" and
    the "Interphone-Radio" switch on "Radio" while talking.  

(4) Do not talk rapidly.

(5) Do not have the telephone transmitter away from the mouth while 
    transmitting.

(6) Do not "cup" the hands over the telephone transmitter.

(7) Do not shout into the telephone transmitter.

(8) Do not forget to leave the "Receive-Transmit" switch on "Receive" when 
    not using the set.

(9) Do not become impatient if you do not hear incoming signals immediately.

(10) Do not expect satisfactory operation over more than five miles range.

(11) Do not forget to put the " Interphone-Radio " switch on "Radio" after
     talking over the interphone.

(12) Do not touch any uninsulated parts of the set while the switch is on
     "Transmit."

(13) Do not tinker with the set.

(14) Do not forget to note any cause as to failure of the set to operate.

(15) Do not fail to study the instructions thoroughly.