Clarification of Answer by
snapanswer-ga
on
03 Jan 2003 01:20 PST
Thank you for the rating and the tip. I am happy that you found the
answer useful.
I will try my best to add some additional details, though, I suspect
that the service staff at Fabcorp (listed below), Ramsey Electronics,
or Aerialix would have the most accurate information about what you
might expect for "real world" results.
The dbi relationship to distance is a tough one, because environmental
factors play a huge role in performance. I can tell you that the
12dbi yagi antenna created from a Pringles can is expected to have a
point to point range of at least 10 miles. However, an
omnidirectional antenna would not have nearly the same range at that
dbi. For example, the description of the 6dbi omni antenna at Ramsey
Electronics suggests that they were able to get 11Mbps at 1/4 mile
with a hill blocking the line of sight. From what I read, every 3dbi
is a doubling of gain. If I surmise (perhaps incorrectly) that the
range approximately doubles as the gain doubles, than a 12dbi omni
antenna might be comfortable with a mile range in poor conditions,
further in good conditions. Also, one might consider that at the
further distances, you may have a signal, but not one that can deliver
11Mbps. However, you may find that even 2Mbps is adequate for many
applications.
You may want to reevaluate your choice of the DA25, because I believe
its specialty is reception rather than broadcast (I note that from the
way the description is written). I suspect you will end up wanting
the highest dbi antenna that you can legally use under FCC
guidelines... which might lead you to the Aerialix or an even higher
gain antenna from another vendor. Or, you may want to look at some of
the premade kits available affordably from Fabcorp:
http://www.fab-corp.com/
In the case of the Fabcorp kits, you would simply connect the antenna
to the DLink or Linksys wireless router that you purchase separately.
(Note that you want to keep the length of the wire from the wireless
router to the antenna as short as possible {less than five feet if
possible} to maintain signal strength). You would connect your
Internet connection to the wireless router.
Since it sounds like you are planning to simply have one antenna
broadcast over a radius, that's it for setup. You would then use you
wireless PDA or laptop and see what distance you can reach reliably.
(Depending on the environment and interference you encounter, you may
need to set up multiple antennas with overlapping radii to cover your
desired area. I note in the material that typically point-to-point
antennas are used for reliable distances greater than 1/2 mile.)
You may find these links helpful in understanding the setup of this
type of network:
Range Extension Discussion:
http://www.vonwentzel.net/ABS/Antenna/
FCC Limitations
http://www.80211-planet.com/tutorials/print.php/1428941
Cityshare: Sharing Internet Access Overview
http://www.cityshare.net/howtos/overview.asp
Cityshare: Simple Wireless Network (with Diagrams)
http://www.cityshare.net/howtos/wireless.asp
I hope that helps.
