Explaining RangeMax™ Antennas

RangeMax equipment uses a number of antennas, while other products usually use one at a time.

The simplest antenna configuration is a single antenna which is used both to transmit and to receive. This configuration is used on most networking equipment. Antennas transmit and receive in a fixed pattern; in NETGEAR equipment often one that's omni-directional (as you would see it from above, a circular donut shape), or one that's more directional (a figure 8, or an oval shape radiating mostly in one direction).

Some non-RangeMax equipment has two antennas. In this configuration, for example with the WG302 access point, the antenna with the better signal is dynamically determined every few moments, and the other one is turned off.

MIMO technology and spacial multiplexing is much more complicated, because routers and access points use a number of antennas which transmit and receive at once. (Ethernet RangeMax adapters still use a single antenna, however.) This technology removes much of the guesswork in antenna placement by constantly assessing a number of ways of transmitting. This technology is so complex, in fact, that the IEEE standards committee — which is responsible for recommending standards to be used around the world — does not plan to finalize the 802.11n standard perhaps until 2007.

In the meantime, creative companies are developing technology which customers can have right now. Because the 802.11n standard is not finalized, it is not possible for any company to claim their current MIMO products will be compatible. There are now years of experience with MIMO technology without 802.11n, while the first generation of 802.11n has yet to be produced. Therefore the existing technology is likely to continue, even after 802.11n is finalized.

Why does RangeMax 240 have 3 external antennas while RangeMax products have several internal ones?

The RangeMax products with internal antennas use one transmitter and one receiver, along with a combiner which accesses each of the antennas selectively. It makes use of diversity, while the RangeMax 240 also uses spatial multiplexing, autochannel, and channel expansion. (Channel expansion is not legal in Japan, therefore the maximum data rate there is 1/2 as great.)

The RangeMax 240 products with 3 physically adjustable external antennas use multiple transmitters and multiple transmitters. While these antennas need to be positioned manually, the advantage is that they are much faster than other wireless technology.

NETGEAR is still intensively researching variations of RangeMax MIMO. No one design has proved itself superior in all ways. When we discover technology that's outstanding, we make it available.

Maximum wireless signal rate derived from IEEE Standard 802.11 specifications. Actual data throughput will vary.
Network conditions and environmental factors, including volume of network traffic,building materials and construction, and network overhead, lower actual data throughput rate.

N101588.asp Dec. 1, 2005