Choose a Standard (A vs B vs G)
The first thing you need to decide is which type of card you need: 802.11b, 802.11a, 802.11g, or a combination: Be careful of the new N series devices as you need to use the same manufacturer's card and access point to take advantage. The 802.11a and 802.11g both offer a rated 54Mbps. Although at different frequencies. 802.11a uses the 5GHz band, 802.11g uses the 2.4GHz band. 802.11g is backward compatible with 802.11b, and is the primary frequency used at Wi-Fi hotspots. 802.11a is popular mostly with consumer electronics vendors, and with enterprises interested in voice applications, as well as Point to Point backhaul solutions. The combination cards are useful when you are not sure what frequency will be available, and will be prepared for all three.
Antenna Design:
Antenna design is crucial to the performance you will get out of your USB adapter, or PCI card because it determines both signal strength and receive sensitivity. Most standard cards only offer about 30mW of transmit power when sending data, and a receive sensitivity of about -80dBm to ‑90dBm. Special high-powered 200mW cards with -90dBm to -96dBm of receive sensitivity offer huge increases in reception (a 3dB difference represents double the sensitivity). Cards with better sensitivity will let you get further away from the access point while still maintaining a usable wireless signal. Having a better card will allow you to park your RV or Trailer farther away from the main office Wi-Fi antenna, yet still surf the Internet at a reasonable speed. (Or you can mention to the park owner to call GNS Wireless LLC.)
The first thing you need to decide is which type of card you need: 802.11b, 802.11a, 802.11g, or a combination: Be careful of the new N series devices as you need to use the same manufacturer's card and access point to take advantage. The 802.11a and 802.11g both offer a rated 54Mbps. Although at different frequencies. 802.11a uses the 5GHz band, 802.11g uses the 2.4GHz band. 802.11g is backward compatible with 802.11b, and is the primary frequency used at Wi-Fi hotspots. 802.11a is popular mostly with consumer electronics vendors, and with enterprises interested in voice applications, as well as Point to Point backhaul solutions. The combination cards are useful when you are not sure what frequency will be available, and will be prepared for all three.
Antenna Design:
Antenna design is crucial to the performance you will get out of your USB adapter, or PCI card because it determines both signal strength and receive sensitivity. Most standard cards only offer about 30mW of transmit power when sending data, and a receive sensitivity of about -80dBm to ‑90dBm. Special high-powered 200mW cards with -90dBm to -96dBm of receive sensitivity offer huge increases in reception (a 3dB difference represents double the sensitivity). Cards with better sensitivity will let you get further away from the access point while still maintaining a usable wireless signal. Having a better card will allow you to park your RV or Trailer farther away from the main office Wi-Fi antenna, yet still surf the Internet at a reasonable speed. (Or you can mention to the park owner to call GNS Wireless LLC.)