Wireless communication is booming and many users are finding that some types of wireless networks are more effective than others.
For example, many Wi-Fi networks do not offer a coverage area that is large enough for an organization’s needs, or the ability to connect a sufficient number of devices, or enough dependability for critical communications. Another option, public cellular networks, might not have the reach your organization needs or offer the local flexibility and control that Wi-Fi can.
In this climate, Citizens Broadband Radio Service (CBRS) networks have emerged with a single platform that meets the diverse needs of countless organizations. It offers a spectrum that can be used exclusively by an organization as well as more coverage, capacity, security, and control.
The first part of this blog post details the traits and main benefits of a CBRS network. The second part explains the importance of protecting a CBRS network from destructive power transients. We conclude by recommending a solution in the form of a quarter-wave stub surge protector.
CBRS: Wireless Broadband on Your Own Frequency
The Citizens Broadband Radio Service is a wireless communication spectrum in the United States that allows for shared access between multiple users in the 3.5 GHz frequency band. The Federal Communications Commission (FCC) created the CBRS to increase access to wireless broadband services while also providing opportunities for innovation and growth in wireless technologies.
The CBRS is unique in that it allows for a three-tiered sharing system where incumbent users, such as government agencies and satellite providers, have priority access to the spectrum. However, once these incumbent users have been allocated their required spectrum, the remaining spectrum can be shared among priority access licensees (PALs) and general authorized access (GAA) users.
The CBRS is expected to lead to increased access to high-speed wireless broadband services, especially in rural and underserved areas, and to enable the development of new and innovative wireless technologies.
Benefits of Using a CBRS Network
A CBRS network offers several solid benefits over other types of wireless connectivity, including:
- Dedicated spectrum: Unlike Wi-Fi and public cellular networks, which operate on unlicensed or shared spectrum, the CBRS provides a dedicated spectrum that can be used exclusively by an organization or group of organizations.
- Better coverage: The CBRS spectrum operates in the 3.5 GHz band, which provides better propagation characteristics than the higher frequency bands used by many Wi-Fi and cellular networks.
- More capacity: The CBRS provides access to up to 150 MHz of spectrum, which can provide significantly more capacity than Wi-Fi or public cellular networks.
- Improved security: The CBRS includes security measures to prevent interference and unauthorized access, which can provide a more secure communication environment than public Wi-Fi or cellular networks.
- Greater control: The CBRS provides organizations with greater control over their wireless network, including the ability to allocate spectrum and manage interference.
Disruptions from Power Surge
Lightning strikes in the United States about 20 million times a year. CBRS networks, like all systems of electronic connectivity, are vulnerable to being damaged by lightning and other causes of power surges and transients. The disruption, which can be extremely costly, can come in three forms: physical damage, induced voltage, and EMI/RFI interference.
SPDs to the Rescue
To prevent lightning strikes and power surges from damaging CBRS equipment, it is important to install surge protection devices (SPDs) such as lightning arrestors and surge protectors at the antenna and power/data connection points. SPDs typically work by providing a low-impedance path to ground for the surge current, effectively shunting the excess energy away from the equipment.
Quarter-Wave Stubs: Faster, Tougher
One type of SPD that is particularly effective for use with CBRS networks is the quarter-wave stub RF surge protector. They stop surges faster than other types of protectors, require no maintenance and can withstand repeated surges without being damaged.
A quarter-wave stub SPD is a type of coaxial cable that is cut to a specific length, typically one-quarter of the wavelength of the frequency being used. The quarter-wave stub works by reflecting any surge voltage that is present back towards the source, preventing it from reaching the equipment. When the surge voltage reaches the quarter-wave stub, it encounters an impedance mismatch that causes the voltage to reflect back down the cable towards the source. This reflected voltage combines with the original surge voltage, canceling it out and preventing it from reaching the equipment.
Quarter-wave stubs offer three advantages over other types of SPDs:
- Quick response: A gas discharge tube takes about 100 nanoseconds to become conductive when a surge hits, while a quarter-wave coaxial protector responds instantly.
- No maintenance: A gas discharge tube surge protector occasionally needs a tube replacement, requiring money and time to install. A quarter-wave stub surge protector needs no maintenance.
- Longer product life: While a single surge from a cell tower might destroy a gas discharge tube, a quarter-wave stub surge protector can withstand many surges with no damage.
Extended-Range SPDs for CBRS
PolyPhaser offers a line of quarter-wave stub RF surge protectors with frequency ranges that are well suited for use with CBRS networks. Our QWP series of extended-range SPDs are loaded with useful features for all major cellular bands up to CBRS. They deliver low-PIM performance, an extended-range passband of 555 MHz to 4.5 GHz and quarter-wave stub protection. As the table below shows, one model has 7/16 DIN connectors, one has 2.2-5 connectors, and two models have 4.3-10 connectors.
Following are the common features and applications of Transtector’s extended-range quarter-wave stub protectors:
Features:
- Extended-range broadband from 555 MHz to 4.5 GHz
- DC block topology
- Repetitive strike protection
- Low PIM
Applications
- CBRS networks
- Cellular
- Distributed antenna systems (DAS)
- Emergency response systems
- Public safety systems
PolyPhaser’s line of quarter-wave stub RF surge protectors with extended-range passband are in-stock and available for same-day shipping. For more information, contact us at +1 208 635 6400.
