Radiomen in the Vietnam War faced a 5-second life expectancy

At the height of the Vietnam War, up-and-coming commo guys who wanted to learn the art of radio operation would walk into a classroom and see a huge number five written on the chalkboard.

Inevitably, someone's curiosity would win out and they'd ask what the big number meant. The instructor would then calmly tell them, "That's your life expectancy, in seconds, in a firefight. So, listen up and you might learn something that'll keep you alive."

That number wasn't some outrageous scare tactic. During the Vietnam War, the odds were tremendously stacked against radio operations — and that 5-second life expectancy was, for some, a grim reality.

To make matters worse, you can't really control the volume on those radios since the dial was on the wearer's back. Radio chatter could give your position away, too.

In all fairness, that number was on the more extreme side of estimates. The life expectancy of a radio operator in the Vietnam War ranged between five to six seconds all the way up to a slightly-more-optimistic thirty seconds, depending on your source. If you look at all of the things the radio operators were tasked with, it becomes abundantly clear why commo guys weren't expected to last long.

The first and most obvious tally in the "you're screwed" column was the overall weight of the gear radio operators were expected to carry into battle. The PRC-77 radio system weighed 13.5 lbs without batteries. Toss in batteries, some spare batteries, and the unsightly, large encryption device called the NESTOR and you're looking at carrying 54lbs on your back at all times. Now add your weapon system onto that and try to keep up as you fight alongside your unencumbered brethren. It took a lot of getting used to — but they managed.

If the weight wasn't problem enough, next comes the antennae. They weren't all too heavy, but they were extremely uncomfortable to use and would often give your position away to the enemy. The three-foot version was easier on the radio operator, but it wouldn't work in thick jungles. For that environment, the radio operator needed a ten-foot whip antenna to stick out of their back, which was a great way to draw unwanted attention.

The Viet Cong knew what it meant to take out a guy with a giant, ten-foot antenna sticking out of their back — you might as well have painted a bullseye on them. You take out the radio operator and you effectively avoid dealing with air support. Additionally, it was well known that a radio operator's place in the marching order was at the heels of the officer-in-charge — two high-priority targets in one spot.

And it wasn't just the bullets that radio operators had to watch out for. The large antenna also acted as a targeting point for mortars and other explosives. All they had to do was aim for the antenna and they could wipe out anyone near the radio operator. As terrible as it sounds, this meant that the radio operator would sometimes move in isolation, away from the rest of the squad.

It's unclear exactly how many radio operators lost their lives during the Vietnam War. While many radio operators were fulfilling their MOS, others just had a radio strapped to them in times of need. One thing is for certain, though: Being a radio operator back in the Vietnam War puts you among the most badass troops the military has to offer.

To hear one of these badasses explain what life was like in his own words, check out the video below.