What is dbm

Determining minimum signal strength requirements in the coverage area is almost alway part of the network requirements list. Desired signal strength for optimal performance varies based on many factors, such as background noise in the environment, the amount of clients on the network, what the desired data rates are, and what applications will be used.

Wi-Fi signal strength is tricky. The most accurate way to express it is with milliwatts mW , but you end up with tons of decimal places due to Wi-Fi's super-low transmit power, making it difficult to read.

For example, dBm is 0. Some adapters use a scale of , and others Ultimately, the easiest and most consistent way to express signal strength is with dBm , which stands for decibels relative to a milliwatt.

The first thing to understand about dBm is that we're working in negatives. Next, it's important to know that dBm does not scale in a linear fashion like you'd expect, instead being logarithmic. That means that signal strength changes aren't smooth and gradual. The Rule of 3s and 10s highlights the logarithmic nature of dBm:. So what signal strength should you shoot for? For simple, low-throughput tasks like sending emails, browsing the web, or scanning barcodes, dBm is a good signal strength.

When you are close to the tower, the signal is quite strong. By the time it reaches your home, it has a lower dBm. Measured in dBm, a signal of greater than dBm is considered an excellent signal in all networks. A poor signal will be dBm or worse in 3G networks and dBm or worse in 4G networks.

It is important to take measurements in several areas to determine where you have the strongest signal strength. When placing a Wi-Fi router or modem, test signal strength and place the device in that particular space. Cell phone or signal bars are subjective and generally indicate the relative strength of the available signal.

The type of cell phone you have as well as the manufacturer can affect how many bars are illuminated as well. You and someone else can be sitting in the same room, you have 3 bars and they have 4. You are using the same cell provider, but, for example, one of you has an iPhone and one of you has an Android. If you look at the dBm, it might be the same. Apple, in particular, is notorious for "inflating" the worth of the bars on their cell phones - hence why it's important to know what dBm is.

What that really means is that your signal strength is excellent at about dBm. Seems much better, right? Not necessarily. Excellent signal strength for 4G is around dBm. In this case, you may have a stronger signal with the 3G!

Check the dBm to see what your strength really is. On Android phones, the signal strength can be found in the Settings menu. The signal is listed in dBm signal strength and ASU. ASU stands for Arbitrary Strength Unit and is a value proportional to the received signal strength measured by the mobile phone. It can be translated to dBm, but there are different formulas depending on whether you are using 2G, 3G or 4G networks. The iPhone has a Field Test Application to access and will give you the same information as above.

This App will give you a ton of information. You will notice that the signal strength changes constantly. I find the Map page fun because I can drive around and see where the signal is strongest. This means that power — in our case, signal strength — is measured in reference to one milliwatt, and can be calculated as ten times the log of the signal strength in milliwatts.

The dB simply quantifies the ratio between two values, and those values are measured by dBm. So once the dBm has been established, only then can you measure any change in decibels dB. Its capability to express values both large and small in short form makes dBm the measurement of choice in radio, microwave, and fiber optic networks.

In the world of cellular signal boosters, dBm measurements represent the strength of a signal at any given location, as well as the amount of power an antenna is capable of amplifying. Typically, a strong outside signal would clock in somewhere around to dBm, while anything below dBm would be considered weak means no signal at all. The use of an indoor antenna could boost that outside dBm signal exponentially — for example, an indoor antenna that is radiating dBm can effectively cover about 3, square feet.