I recently asked a neighbor what it is that transmits his cell phone calls and emails. He replied, “I have no idea; the telephone network?”

I immediately sprang into action, because not knowing how cell phone calls and emails get transmitted is becoming a dangerous thing. It may not be a big deal to you if you call home to get the shopping list and you cannot get through. “I’ll just wing it,” you say. But what if your life depended on your call getting through?

My godfather is wearing a pacemaker now (he’s in his eighties). That device “transmits” his vitals to his doctor, 24×7. If he starts to a-fib, the doctor can initiate a signal back to the pacemaker to correct the fibrillating heart. Guess what? The same medium that transmits cell phone calls and email also transmits life-saving signals like the one to my godfather’s pacemaker. These days, those transmissions use the electromagnetic spectrum, or EMS, or spectrum, for short.

The average user doesn’t need to know much about the spectrum, but you need to know at least the basics. Up until about 30 years ago, most telephone calls were transmitted on copper wires called the POTS: Plain Old Telephone System. Most emails were transmitted that way, too. Then, throughout the 90’s the wireless telecommunications industry started building out the cellular network – those unsightly towers that appeared above the tree lines and city horizons. At the bottom of those antenna towers are Base Stations – the operating centers of the cell towers. These are the brains behind the new telephone network: the one that moved our communications from the copper wires into the airwaves.

Transmitting voice over the air waves has been around since the turn of the 20^th century; it’s called radio. First came AM, then FM. Now, Sirius XM. Radio signals get transmitted over the spectrum. This is a good place to start to build understanding of the spectrum. Most everyone knows what a radio is.

Nowadays, what most people don’t realize is that nearly all personal business is generated in a smart device (like your cell phone, or Apple Watch) and morphed into a radio wave that gets transmitted over the airwaves a lot like a radio signal, just at a different frequency. Let’s stop right here because this is a really important point. This means that every single one of your text messages, online shopping orders, financial data, emails, cell phone calls, just about everything you do every day with a smart device is transmitted over the spectrum. Even the business you conduct from home on your PC ends up being transmitted through the EMS.

If you’re wondering why this is, that is a topic for another post. It is relevant to mention that the POTS would not have the capacity to transmit everything that is being sent or will be sent. Our entire world now rides on the electromagnetic spectrum.

Now, here’s something you may have never considered: your access to the spectrum could be denied.

Let’s examine this. When you are listening to your FM radio in your car, you drive through a tunnel and what happens? The music stops. Did you ever stop to ask yourself why? It’s because the FM portion of the electromagnetic spectrum doesn’t go through concrete. Tunnels block FM radio signals. When you look at your cell phone and, “only have two bars,” it’s because your smart device is in a location where cellular signals are degraded or blocked. Again, when your life isn’t on the line, no big deal. But for our warfighters in combat, it is a big deal. For my godfather, it is a big deal.

Luckily, our wireless telecom overlords have been generous with their efforts to build out the wireless network to serve up spectrum just about everywhere. So, a lot of us don’t experience something called “spectrum denial” every day, or even often. Also, cable providers have been generous enough to offer a “bigger pipe” into your home so Suzy can play, “Fortnite Battle Royal,” Danny can FaceTime Grandmamma, and Mom can view her real estate sale videos all at the same time.

Unfortunately, this doesn’t mean the spectrum will always be there for your pleasure and convenience. In fact, our enemies have been watching our growing dependence on the spectrum and have announced their plans to deny us access to the spectrum in battle. That battle could occur abroad, or it could occur right here in our hometowns.

Closer to home, truck drivers have purchased GPS jammers to hide their position from their bosses. As they happily drive down the road (or take a nap), they are unknowingly jamming people’s Internet, confusing the navigation systems in private autos, compromising pilots’ ability to navigate, sending people’s garage doors up and down, you name it. If they had known that their simple attempt to buy a few hours of sleep had the potential to disrupt so many other systems, would they have bought such a thing?  I hope not.

The spectrum is a common public good and, as a community using it, we need to raise our mutual level of awareness and hopefully cooperate more in the spectrum.

If you take one thing away from this post today, know this: the thing transmitting your texts and cell phone calls (the spectrum) can and will be denied. This means you may not be able to call home when you want to or use navigation to get where you’re going.

Take this with you as well: when someone asks you what it is that transmits your cell phone calls and emails, tell them, “Why, it’s the spectrum, of course.”

Next time: let’s learn about ways to protect our smart devices from being denied spectrum, using EP – Electromagnetic Protect features.

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