What Is RF Interference, What Causes It, & How To Block It

Many devices emit radio frequency (RF) radiation, including mobile devices, Wi-Fi networks, remote controls, cordless phones, Bluetooth headsets, and radio and TV broadcasts. Microwave ovens and fluorescent lights are other common sources of RF radiation.

What Is an RF Signal?

The term RF signal (radio frequency signal) refers to a subset of the electromagnetic spectrum from around 9kHz to around 300GHz.

Radio Frequency Range

The radio frequency ranges include:

• Very low frequency (VLF) — 9kHz to 30kHz
• Low frequency (LF) — 30kHz to 300kHz
• Medium frequency (MF) — 300kHz to 3MHz
• High frequency (HF) — 3MHz to 30MHz
• Very high frequency (VHF) — 30MHz to 300MHz
• Ultrahigh frequency (UHF) — 300MHz to 3GHz
• Super-high frequency (SHF) — 3GHz to 30GHz
• Extremely high frequency (EHF) — 30GHz to 300GHz

What Is RF Interference?

RF interference occurs when RF radiation disrupts the normal functions of an electronic device or network. It can also be caused by conduction through a power cord. Cables can be both sources and receivers of RF interference, conducting or radiating RF signals or picking up RF signals from other sources.

What Are the Causes and Problems of RF Interference?

RF interference is hardly a new phenomenon. Anyone who’s heard parts of two radio broadcasts simultaneously has experienced the overlap of radio station signals.

What Provides the Greatest Source of RF Interference?

However, wireless networks are a leading source of RF interference today. As more devices connect to a network, the RF spectrum becomes so crowded that frequency bands often overlap. Other wireless devices that use the same 2.4GHz frequency as Wi-Fi can also interfere with network connectivity, as can nearby microwaves and other types of equipment.

RF interference can have critical consequences on IT equipment and networks. Although Wi-Fi devices are designed to accommodate some degree of interference, they will wait for interference to die down before sending data packets. The result is dropped connections and degraded performance.

The problem can be acute for organizations that must test operating systems, firmware, and applications across a multitude of devices. Many devices use wireless connectivity for communication. Real device testing requires the segregation of the equipment to prevent wireless signals from propagating.

How to Block RF Interference

For mobile applications, the quantity of devices required for testing is very high (hundreds or thousands), making it impossible to maintain adequate distance between them. The only remedy is to shield the equipment.

A number of materials can be used to block RF signals, including copper, aluminum, and steel. For example, cables are typically shielded with a thin aluminum foil or braided copper wires. Individual devices can be placed inside simple shielded boxes, but this is too inefficient for real device testing at scale.

A better approach is to utilize shielded cabinets. For example, the Enconnex line of real device testing racks and cabinets includes shielded units that effectively attenuate RF signals providing up to 85dB of attenuation at frequencies ranging from 1MHz to 10GHz. DevShield cabinets are constructed from aerospace-grade shielded aluminum. All the seams and penetrations of the cabinet are shielded using copper-nickel gaskets for maximum protection. They effectively eliminate the problem of RF interference while making it easy to access and manage devices in the lab or data center environment.

A Wide Range of Options

Enconnex DevShield cabinets have a 600x1300mm standard data center rack footprint, simplifying integration into the data center. Yet they can support up to 400 devices in a single cabinet that incorporates compute, storage, networking, and power resources. Ten powerful fans provide 235 CFM of airflow each to rapidly exhaust heat out of the enclosure.

The 42U (customizable) DevShield cabinet features customizable I/O panels and power line filter. Each unit can be customized with various sliding shelves and cable management options. Enconnex also offers the 6U DevShield Mini rack mountable enclosure for smaller-scale testing.

RF interference is a growing problem due to the proliferation of devices competing for the same airspace. Enconnex DevShield cabinets protect against RF interference with a flexible, scalable solution that fits any data center or lab environment.