Obstructions and height of the transmitter are more important than power at these frequencies.
Of course Wi-Fi USB with external antenna will outperform dongle with internal antenna.
In U.S. maximum transmitter power is 1000mW (1W) but low power dongle will still work if users can see the Pi.
I measured this dongle + Pi out to 300m outdoors. RAV battery powered. Pi was about 1m off the ground. Transmit power is 17 dbm (0.05W):
Tenda W311Ma
Also this one, 250m outdoors:
Think Penguin
Wi-Fi USB + Pi does not require a hub for power. I use 2A supply from Amazon, or RAVPower external battery with 2A output.
Power supply
RAVPower battery
Of course Wi-Fi USB with external antenna will outperform dongle with internal antenna.
In U.S. maximum transmitter power is 1000mW (1W) but low power dongle will still work if users can see the Pi.
I measured this dongle + Pi out to 300m outdoors. RAV battery powered. Pi was about 1m off the ground. Transmit power is 17 dbm (0.05W):
Tenda W311Ma
Also this one, 250m outdoors:
Think Penguin
Wi-Fi USB + Pi does not require a hub for power. I use 2A supply from Amazon, or RAVPower external battery with 2A output.
Power supply
RAVPower battery