Does higher dBi mean slower speed?

[Carlos1010]

Hi all,

When shopping for usb network adapter to plug in your PC, I usually run into the term dBi. I read about it and the higher it is the farther the signal of the adapter can reach but the connection get's very narrow. But also when reading it didn't talk about the speed of the adapter. Does having more dBi mean that the signal speed will decrease? Thanks in advanced!

[2FA]

It just means the actual physical power of the signal from the antennae. You typically want higher power as it is less susceptible to noise and interference which also allows for better penetration through walls.

[mariushm]

dBi = decibels relative to an isotropic radiator.

 

The higher the number, it means the antenna is more efficient,  better signal amplification, stronger signal sent in the air by the antenna, better reception of signals.

 

copy paste from tp-link

 

Decibel (dB)
This is the unit of measure of loss or gain. This value represents the ratio between two amounts of electrical or acoustical power received. In basic terms, it’s a measurement of power.

 

Decibel-isotropic (dBi)

This is a hypothetical reference point where an isotropic antenna transmits a signal in a perfect sphere.  It should be noted that a perfect sphere is impossible to create so 0Dbi is a realistically impossible number.

 

Antenna Gain
Also simply known as ‘gain’, this is a measurement of power that represents the efficiency in which the antenna converts electricity into radio waves.  When speaking in terms of antennas:
 

Gain + dB = dBi of an antenna  

The gain can affect the direction in which the antenna operates. The higher the gain, the more directional the antenna is. The antennas power doubles for every 3dBi.

[SCHISCHKA]

 

30 minutes ago, Carlos1010 said:

I read about it and the higher it is the farther the signal of the adapter can reach but the connection get's very narrow. But also when reading it didn't talk about the speed of the adapter. Does having more dBi mean that the signal speed will decrease?

here is a cool picture i googled:

 

dBi is more about the effective range and physical area in which you can expect a decent rf signal. The actual speed doesnt change but the speed you will observe will change because a poor signal will cause an increase in dropped packets or incomplete packets.

 

 

[leadeater]

High gain antennas can also be bad, they amplify both the signal and noise equally. Higher output with a lower gain antenna is much better, it's unlikely these types of details will be listed on a USB adapter though.

 

Signal to Noise Ratio (SNR) more accurately tells you if your actual throughput is going to be good or not.