Antenna Technology
Overview
Antenna polarization is an important
consideration when selecting and installing antennas. Most
wireless communication systems use either linear (vertical,
horizontal) or circular polarization. Knowing the difference
between polarizations can help maximize system performance
for the user. Circular polarization is more
efficient than elliptical polarization because circular
polarization uses less energy in propagating the signal,
thus delivering more power.
Line-of-Sight
High-frequency systems (e.g. 2.4 GHz and
higher) that use linear polarization typically require a
clear line-of-sight path between the two points in order to
operate. Such systems have difficulty penetrating
obstructions due to reflected signals which weaken the
propagating signal. Reflected linear signals return to the
propagating antenna in the opposite phase, thereby weakening
the propagating signal. Conversely, circularly-polarized
systems also incur reflected signals, but the reflected
signal is returned in the opposite sense largely avoiding
conflict with the propagating signal. The result is that
circularly-polarized signals are much better for penetrating
and bending around obstructions.
Thus, when a line-of-sight path is impaired
by light obstructions (e.g. foliage or small buildings),
circular polarization is much more effective than linear
polarization for establishing communication links. In
addition, circular polarization is more resistant to signal
degradation due to inclement weather conditions for the same
reasons.
Software Advantage
with Concierge
This is a Linux based build-it-yourself
software for system administrators, small business owners,
small/home office workers and multi-PC households, that will
let them convert a standard PC into a network gateway or
appliance server. Building and using the appliance requires
no operating system, networking or server expertise. This
software is the most easy to use, affordable and complete
client-server networking solution on the market today.
Features/Functions Unlike other thin server/appliances,
Concierge software supports dual network configurations and
offers a multiple set of features/functions that can be
enabled as needed. When used in the Small Business
configuration, the PC running Concierge software can
connect an unlimited number of IP-enabled clients to the
Internet via a single analog/DSL/ISDN/Cable modem or
router/switch/hub connection. Built-in DHCP, DNS and NAT
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network or network segment without having to install
software on the clients. When used in the Work Group
configuration, the PC becomes a network-ready appliance
server that you simply plug into a pre-existing network. In
either configuration, the software comes with an e-mail
server, print/file server, web server and web caching engine
to provide all server functions required by a small network.
Additional features supported include VPN/firewall, UPS, SMP
and others. Installing the software takes less time and is
similar to installing Windows on a standard PC, while
network configuration is performed with a Setup Wizard. This
kind of flexibility and features can only be found in very
expensive/complex multi-vendor client-server solutions. It
offers significantly better price/performance than other
appliances or peer-to-peer home networking products.