the panel is joined to the frame so that chefs and controls can be properly placed this is the extension shaft to the bands which by the use of this bands which are connected to the exciter and driver stages it's possible to change frequencies very rapidly that's vitally important in military operation the final amplifier tuning condenser assembly was built as a unit on the feeder table it is placed carefully in position before this radio frequency direct joins the main assembly line the standoffs the neutralizing condenser is mounted on the standoffs added here are the antenna binding posts through which passes the output of the transmitter this unit is now carefully inspected before it moves into main assembly every element no matter how large or small is inspected and tested before it goes into a transmitter when the radio frequency tech joins the main assembly here the big job is nearly done a steady flow of finished units has been made possible by intelligent planning of the work at all how it crafters plans perfect for the nation with the suppliers and subcontractors and hundreds of skilled and tireless hands now the relays are covered the smaller tubes are stacked in place and the completed unit is ready to leave the assembly line the transmitter is now ready for the first of many tests it will receive before it this is the electrical testing room where the transmitters output modulation and keying are accurately measured and recorded this work calls for plenty of technical skill and knowledge so the staff h principally made up of experienced radio amateurs signal corps inspectors watch closely these important steps in controlling both the quality and performance of the transmitter this test measures the radio frequency output of the transmitter instead of allowing the signal to radiate over an antenna these blokes called the dummy antenna converts the r f outputs into heat another important test is the one made for overload the purpose of this is to make sure the relays respond properly to protect the circuits this is also done to determine the capacity of the entire transmitter to absorb a temporary overload in normal operation without breaking down next the transmitter is given a trial it's sending code signals when operated in this manner the audio amplifier and modulator are not used the flashing of these rectifier tubes shows how the key simply makes embrace the output to form the characters of the telegraph co to check how well the transmitter responds to all essential voice free sees the is still a graph is used this detects any distortion and locates of what point the distortion occurs less transmitte shows a normal frequency response when the lid goes on the transmitter that means it has passed all the electrical tests with an a one rating it's ready now for the signal corps truck in another part of the plant the radio receivers are being mounted on a table assembly that makes up the listening end of this communication units each table is equipped with two similar radio receivers one operates on the main power supply and the other from an auxiliary battery the entire assembly is tested for proper operation as a unit the two receivers can be operated simultaneously this is the speech amplifier two separate operating positions are provided part of the table assembly includes two loud speakers to field telephone instruments and a portable typewriter this is the final step in assembly bringing the transmitter the receivers and the accessories together and installing them in the truck once the equipment is mounted inside this door it becomes officially the s c r two ninety nine it's on the way to the front easy does it there's no room to spare here and there is plenty more to be put in every inch of space is accounted for in this truck and these men know how to use it the place for everything and everything goes right into place quickly and securely while the transmitter is being bolted to the floor the table assembly with its receiving equipment moves in accuracy and design and construction makes it possible to save many valuable hours throughout the entire production assembly of the unit there goes the world cabinet that holds the additional operating parts extra calls tuning units condensers and here is the bench that contains the tools and spare parts radio man's hope chest and this is what it looks like when the operators step in at the far end the transmitter with the antenna tuner on top of it on the right the of cabinets on the floor of the long bench for the operators both of these are storehouses for parts and accessories on the left wall of the truck the operators table with two receivers speech amplifier control panel and below an electric heater and the two field telephones there goes the s c r tonight a nine out into the field to make its final test on the air there is just one thing missing where's the power coming from the signal corps provides with that in a portable gasoline driven generator that ri trailer behind each truck this generator supplies standard lighting current one hundred seventeen votes a c a transmitter and receiver that operate on this current can be hooked into power almost anywhere here is the mobile power supply a remote control from the truck to the generator makes it possible to start and stop the generator at will the operator prepares for the air test its first call is to central control station w x y k w x y k for calling for a check on the quality of this transmission and standing by and here is communication going off to war over these rams roll hundreds of units that will carry the voice of victory to every corner of the earth like the champion thoroughbred it is the s c r two ninety nine whole boxcar to itself the signal corps unit is built for action and to get into action fast it's a highly mobile radio station that may be set up almost anywhere in battle or invasion activities speed is quite old every minute air force many of which are widely separated through the transmitter flow the reports information timing and the order to advance this is the voice of victor contact may be made with an approaching flight of bombers while they're still hundreds of miles away from the target to coordinate their attack perfectly these fliers must know the present position of our own tanks infantry artillery they get this information by contact with the message center which speaks and listens to the s c r two ninety nine tanks moving into position must be kept informed of the approaching air support timing is vital and the timing of all these movements is controlled through this voice by direct contact with the armored forces head from many small stations scattered miles apart along the battle fronts comes the flesh new the observations the unexpected all clearing through this central station that's how radio helps to time these big movement make them strike most effectively and with the minimum loss of american lives radio communication units are among the first pieces of equipment to go into action whether the attack is on land or se radio communications stay in the fight as long as there are man guns ships and tanks on the move or the life death or victory of all of them depend upon this perhaps one of the most important messages ever issued is the one you're about to hear from major general harry c ingles g signal office of the united states army general ingo's i'm speaking no  as round american soldier to another we in the armed forces regard each of you men and women in this audience as being on our bus and working shoulder to shoulder with us you and you  are responsible for the production and performance of this vital piece of communication a problem you have seen enough to know good communication equipment means to the men out there and what it means to victory you have done a splendid job keep up the good work you have been doing we are asking millions of american soldiers to stake their lives on breaking germany and japan they ask you to keep