RFWiFi Signal Strength: Understanding -70dB vs. -50dBm
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This article clarifies the meanings of “WiFi -70dB” and “WiFi -50dBm,” and also explains the relationship between dB and dBm.
As we know, WiFi (Wireless Fidelity) generally refers to any local area network (LAN) that uses high-frequency radio waves to transmit and receive data over short distances, typically up to a few hundred feet. It’s often also called WLAN (Wireless LAN).
WLANs utilize Ethernet protocols and adhere to the specifications outlined in the IEEE 802.11 standard. The 802.11 family includes various versions like 802.11a, 11b, 11g, 11n, 11ac, 11ad, and more. These different versions are developed to meet varying data rate and coverage distance needs.
(For more details, refer to articles on MiFi vs. WiFi and WLAN tutorials.)
What is WiFi -70dB?
We’ve already defined “WiFi.” The key here is “-70dB.” Let’s break down “dB” first.
“dB” stands for decibel. It represents the ratio between two powers, voltages, or currents. The formula is:
Where P2 and P1 are the power levels at two different points.
Therefore, “-70dB” indicates a path loss. Specifically, it’s the signal attenuation experienced by radio frequency (RF) waves as they travel from a transmitter to a receiver. A larger negative dB value means greater signal loss.
WiFi -70dB thus refers to a path loss of 70 decibels incurred by the radio waves emitted by a WLAN compliant RF device. This suggests a relatively weak signal.
What is WiFi -50dBm?
Again, “WiFi” is covered. Now, let’s focus on “-50dBm.”
“dBm” is a relative power measurement referenced to 1 milliwatt (mW). The formula is:
“-50dBm” typically refers to the sensitivity of an RF receiver. It’s the minimum power level the receiver can detect and still function satisfactorily, meeting the required system Bit Error Rate (BER).
Alternatively, -50dBm could also be a power measurement at various points within a WiFi device or a WLAN system.
WiFi -50dBm indicates that the receiver sensitivity of a WiFi-compliant device is -50dBm. This is a stronger signal compared to -70dBm.
