Saturday, November 22, 2008
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Higher Power
While it may seem that higher power Wi-Fi might help to improve your range, that's not necessarily true, since higher power only helps on transmit, not receive. Thus it's only likely to help if the other end of your connection is using higher power as well, which is often not the case. In other words, what you may well wind up with is an alligator, big mouth but small ears. Also, unnecessarily high transmit power will tend to increase your interference with other Wi-Fi users, making you a bad neighbor. It's usually much better to just improve your antenna, which helps both transmit and receive.
Antenna Location
Higher antenna locations tend to have less interference (e.g., from other boats) than lower locations, so in general it's a good idea to locate the antenna as high as is practical. On a sailboat, the ideal location is at the top of the mast.
Since signal loss in the cable between the radio unit and the antenna increases rapidly with the length of the cable, it's better to locate the radio unit next to the antenna, and use lossless cable to support the radio unit, either USB or Ethernet, both of which have advantages and disadvantages (as noted below).
Automatic Tracking
There are products than can be used to keep a directional antenna aimed at an access point as a boat swings or drifts with precision of better than one degree (e.g., Track-It-TV). However, they are relatively expensive, and they only track in the horizontal plane, so it's important that the vertical beam width take into account rolling and pitching of the boat. Usually a vertical beam angle of 10 degrees or so is adequate for all but the roughest conditions, but even beam angles of 20 degrees or more can still result in substantial improvement in gain over an omnidirectional antenna.
While it may seem that higher power Wi-Fi might help to improve your range, that's not necessarily true, since higher power only helps on transmit, not receive. Thus it's only likely to help if the other end of your connection is using higher power as well, which is often not the case. In other words, what you may well wind up with is an alligator, big mouth but small ears. Also, unnecessarily high transmit power will tend to increase your interference with other Wi-Fi users, making you a bad neighbor. It's usually much better to just improve your antenna, which helps both transmit and receive.
Antenna Location
Higher antenna locations tend to have less interference (e.g., from other boats) than lower locations, so in general it's a good idea to locate the antenna as high as is practical. On a sailboat, the ideal location is at the top of the mast.
Since signal loss in the cable between the radio unit and the antenna increases rapidly with the length of the cable, it's better to locate the radio unit next to the antenna, and use lossless cable to support the radio unit, either USB or Ethernet, both of which have advantages and disadvantages (as noted below).
Automatic Tracking
There are products than can be used to keep a directional antenna aimed at an access point as a boat swings or drifts with precision of better than one degree (e.g., Track-It-TV). However, they are relatively expensive, and they only track in the horizontal plane, so it's important that the vertical beam width take into account rolling and pitching of the boat. Usually a vertical beam angle of 10 degrees or so is adequate for all but the roughest conditions, but even beam angles of 20 degrees or more can still result in substantial improvement in gain over an omnidirectional antenna.
Posted by
drahcir
Labels:
Wi-Fi