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If you’re using a smartphone at a business location that has no WiFi hotspot you’ll have to resort to paying for 4G or LTE service which covers most urban and suburban areas. A laptop user however has more options. A USB external WiFi adapter can give you higher output power and, if capable, the benefits of a larger antenna.

There are dozens of different USB WiFi adapters available. Most have an internal antenna which is probably better than the internal one in your laptop because it’s not surrounded by other electronic components. These adapters are relatively inexpensive and unobtrusive so it’s a good idea to have one in your laptop case. If that doesn’t do the job I recommend getting one that can use an external antenna. That will really boost your WiFi signal output and at the same time improve your receive signal.

A word of warning: Some manufacturers claim very high power output from their USB WiFi adapters. Anything over 2000 milliwatts (2 watts or 33 dBm) is almost certainly a lie and the limit is probably much lower than that. One of mine claims to output 6000 milliwatts!

As for the maximum output power possible for a USB WiFi adapter, no one seems to be saying. According to the USB 2.0 specs, the port only gives up to .1 amps of current when a device is first plugged in. If the device needs more it must request it. The most a device is allowed to draw is .5 amps. Power in watts is equal to: volts x amps. Given that a USB port operates at 5 volts there will be 2.5 watts (5 volts x .5 amps) or 2500 milliwatts of power available. And that 2500 milliwatts is for the entire USB device, not just the radio transmitter. There is other circuitry in the adapter that needs some of that power and please note the transmitter is not 100% efficient.

I’ve stated elsewhere on this site that the transmitter power of your USB WiFi adapter is not the only important factor. Just as important, if not more so, is the receive side. A hot spot might hear you but if you are putting out a booming signal because you’re using a super high power device, you may not be able to hear the reply. So as long as you’re putting out between 500 and 1000 milliwatts, you should be fine for the transmit side. Concentrate your efforts on the antenna setup. That will improve both your transmit and receive performance.

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