At the time when the Titanic sank, 100 years ago this morning, wireless communication was still in its infancy. Marconi had demonstrated the first transatlantic wireless communication only ten years earlier.
Being the only one with the equipment and knowledge to send and receive messages in an emergency is a scenario that has a secret fascination for almost all young radio amateurs. It’s part of the appeal of amateur radio Field Day, the first fourth full weekend in June when amateur radio operators set up emergency radio stations and run them all night, often on generator power.
Working the radio room on the largest ship in the world must have been an amazing job for Titanic’s two radio operators, Jack Phillips and Harold Bride, who were 25 and 22 years old respectively. Using Bride's account from interviews and technical descriptions of the radio equipment, we can imagine what it must have been like for them as the emergency unfolded.
Harold came from the radio suite's sleeping quarters to relieve Jack. As he was talking to Jack, the captain came in and said they had struck an iceberg and they may need to call for assistance. Ten minutes later the captain briefly stuck his head in the door and without elaborating gave a terse order to send out a distress call. 
Jack tapped out the distress signal CQD. The Marconi radio receiver had no automatic gain control, so stronger signals sounded louder in the headphones. Jack had been hearing the radio operators on the nearby Californian very strong a few minutes ago, so they expected an immediate response from them. Unfortunately the radio shack on the Californian had shut it down for the night. Harold joked that he ought to try sending the new distress signal, S.O.S, because if this were really such a grave emergency it might be his last chance in life to use it.
Jack dialed up the gain and started detecting code from a more distant ship, the Frankfurt. He copied the code the and explained their captain had ordered a general distress call. Jack and Herold may have been thinking “Our pointy-haired captain is all fired up, and wants this to go straight to your pointy-haired captain, as if this were some big deal.”
A short time later they noticed the ship was beginning to list and suddenly realized the emergency was real. Their radio station was the most important factor in savings lives on the ship. Their radio had the latest technology: a narrow-band 5kW transmitter, ability operate on either 500kHz or 1000kHz, a sensitive receiver, and an antenna reasonably well-matched for 1000kHz and operable on 500kHz with an antenna tuner. Jack adjusted the receiver, watching for maximum deflection on the meter and listening to the volume change in the headset. He keyed down the transmitter and watched the gauges as he adjusted it, not concerned if the dead carrier emitted as he tuned up created any annoyance. He tapped out CQD and S.O.S, taking care to keep a clean fist (an even spacing of “dots” and “dashes”) and resisting the temptation to send any faster than he could reliably copy. He switched to receive and closed his eyes to cut out any stimuli that might detract his focus away from the sounds he was listening for: pulsed white noise from a wideband transmitter or the beat oscillation tone from an a narrow band transmitter.
A strong reply came in. Jack focused on copying the message onto the logbook without letting too much of his brain power focus on the message content until it was complete. It was the Carpathia. They had been about to shut down the radio for the night but by luck heard the distress call first. The Carpathia's radio operator said their captain was setting a course for the Titanic.
Harold ran to tell the captain as Jack transmitted a more precise location of the Titanic. Harold had to push through a crowd of passengers and crew members scrambling for lifeboats. The radio operators were not part of the passengers or crew. Their uniform indicated they were Marconi Company employees. They lived out of the quarters in the radio suite and took meals in a dining room for Marconi and postal employees. So Harold watched the commotion as a detached observer, as technical people often do in situations when people become overwrought.
When he returned to the radio suite, Harold discovered the voltage on the 100V DC supply coming into the radio room was sagging. The transmitter had a DC motor connected to an alternator generating 100V AC. When the the transmitter was keyed, a transformer converted this to 10,000V AC. They attempted to retune the transmitter at the lower voltage and send to the Carpathia that they were losing power.
The captain came in and told them they had done a good job, they were released from their duties, and it had been good working with them. Jack ignored him and carried on adjusting the radio equipment and maintained intermittent communication with the Carpathia. Outside the radio room, the front of the boat was going under water. Everyone was scrambling for the back. Even as water began to enter the radio suite, Jack remained immersed in the dots and dashes in his headphones. Harold ran to their sleeping quarters and grabbed their warm clothes for both of them and some of their valuables. When he came back, Harold saw a large crewman attempting to steal Jack's life preserver while Jack was engrossed in the radio. Despite being a man of small stature, Harold attacked the crewman. The radiomen overpowered the larger man and knocked him out. They took off running to the back of the boat, leaving the attacker unconscious in the flooding radio suite.
Harold saw people struggling to launch the last life boat. He was attempting to help them when a wave swept him overboard. He swam to another lifeboat and someone helped him into it. Jack was on the same lifeboat, but he died of hypothermia. That morning Harold was taken aboard the Carpathia and treated for frostbite. By that evening, he was operating in the Carpathia's radio room. He remained in the Carpathia radio suite transmitting messages to and from survivors until the ship arrived in New York.
The radio operators' story is based on Bride's account. Details such as exactly at what points they stopped to tune up their radio can only be guessed.
This story from a time when the subject of “electrical engineering” was new and RF was cutting edge rings familiar to engineers today.
