It was my privilege to serve those that were serving our country during 1968 - 1972. Unknown to most were all those amateur "ham" operators that volunteered to work at shortwave radio stations that the military set up. My main service was maintenance and repair to keep those systems going, although I did handle several calls. To explain the difficulty in such communication, first, the VN station had to establish solid contact with the USA-based station. This depended on the sunspot cycles since this 9000-mile communication depended on reflecting the signal off the ionosphere. If the ionosphere absorbed the signal rather than reflect it, then no contact could be made. Once the VN and USA station had contact, then the soldier had to be at that station (base or mobile field) then the USA station had to patch in the family using landlines. If a party line was involved, then that complicated things even more. I always explained the importance of saying over and not making noise since the ham had them on VOX or voice-activated relay. I usually instructed them to cover their phone mouthpiece after saying over and keeping it covered until they heard the other party say over. .
Little appreciated is the radio operators during the Vietnam war. The field operators of course were the first targeted because without communications the troops were unable to call in bombings, etc. Even though the MARS operators in Vietnam that were also fighting soldiers, set up stations to serve another purpose that posed no threat to the enemy, they were also targets and easy to spot because of their antennas. Several of the stations went into bunkers and used hard-to-see wire antennas. I am surprised that there are veterans that don't appreciate the role their fellow soldiers played as radio operators, especially the battle operator which was the most important link in a successful mission. While it is more understandable why some may not appreciate the ham operator MARS soldiers since their mission was different, they were also targets because the enemy would have liked to stop all communication the troops had with the USA. There were a lot of highly encoded communications by radio that the military base radio operators in the USA received from the MARS military operators, many that were also hams. Radiomen in the Vietnam War faced a 5-second life expectancy - We Are The Mighty
It has been a half a century since I last heard the abbreviation. In 67 at the missile base I could call anywhere in the world using the special line no one had access to except military people. I would call from the main gate century post to Lebanon to talk to my girlfriend for a few minutes, the name of the line was autovon undersea line. I got the number from one of the guys working in the radar section. Now when I had gate duty at the launch area where I worked we had no phone, the phone was inside the ready room.