BDA Designs That Are Out of This World

I read something the other day that blew my mind. Not surprising given the wide range of content available these days; however, I read it while editing a technical study guide for radio frequency communication systems. Technical study guides, by their nature, are never mind-blowing. Quite the opposite; editors struggle to make them interesting enough to ensure the reader stays awake. I was on the 25th chapter, deep into the weeds, in Section 8.7, Noise Floor and Noise Power. The section began with this icebreaker: Background noise exists everywhere as a remnant of the Big Bang. This is the leftover echo from the creation of the universe and provides us with an absolute minimum noise floor that can be calculated. I had to read that again to ensure I hadn’t drifted into the cosmos myself. Did this document, written by subject matter experts, state that the odd buzzing sound people call background noise or white noise is actually an echo from the universe’s explosive birth?

I am the Director of Communications at RF Solutions, an engineering systems integration firm specializing in radio frequency communications. In my role, I spend a lot of time reading and editing documents that describe radio frequency communications. There is no doubt that RF emissions are a fascinating topic. Humans cannot detect them with any of our five senses, yet they can be harnessed and used to transmit some of the most crucial information we possess. Discovered in the 18th century, these electromagnetic waves gave birth to wireless technology and have been used for telecommunication, military, public safety, space, and countless commercial applications ever since. But I had no idea that RF engineers used Big Bang’s echo, also known as cosmic background radiation or thermal noise floor, in their calculations. I sent Chris Godwin, our CTO, a text to get more insight. 

LJ: You design BDA systems using the leftover echo from the creation of the universe? 

CG: It’s very cool! We use it to ensure we don’t increase the noise floor at a tower site. 

You know we use amplifiers in buildings to boost signals from First Responder walkie-talkies so they can transmit to a tower or rooftop site for wide-area communications. That is known as the system’s uplink. 

LJ: Okay, but where does the creation of the universe come into play?

CG: Certain buildings require amplifiers covering a range or band of frequencies. These are known as wideband or Class B Signal Boosters. They amplify any signals within their bandwidth, including background noise, which you mentioned is the “echo from the creation of the universe.” If a system is poorly designed, the only way to get strong signals back to the donor site is to crank up the volume (system gain). The problem is that doing so also increases the background noise, sometimes making it impossible for First Responders to communicate. That is called Uplink Noise.

LJ: So, assuming we have no way to control cosmic background radiation, what do we do?

CW: When we design a system with a Class B Signal Booster, we thoroughly consider the background noise in our calculations, so we can ensure that when the signal from the amplifier reaches the donor site, the “noise” component of the signal is not above the thermal noise floor. When a BDA system is designed and installed correctly, you’ll never hear whispers from the Big Bang. 

LJ: I’m always impressed by the depth and breadth of knowledge our engineering team possesses, but on that particular day, it was otherworldly.