printed April 10, 2008
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Phone	Samsung SGH-A737 / SGH-A736	LG CU515	Nokia 6085 / 6086
Current U.S. Carriers	AT&T (Cingular)	AT&T (Cingular)	AT&T (Cingular) SunCom T-Mobile
Global Availability	Released	Released	Released
Avg. User Rating	3.61	3.67	3.82
Specifications
Modes	GSM 850 GSM 900 GSM 1800 GSM 1900 WCDMA 850 WCDMA 1900	GSM 850 GSM 900 GSM 1800 GSM 1900 WCDMA 850 WCDMA 1900	GSM 850 GSM 900 GSM 1800 GSM 1900
Weight	3.16 oz (90g)	3.36 oz (95g)	2.96 oz (84g)
Dimensions	3.9″ x 1.9″ x 0.6″ (99 x 48 x 15.2 mm)	3.78″ x 1.95″ x 0.72″ (96 x 50 x 18.3 mm)	3.62″ x 1.81″ x 0.91″ (92 x 46 x 23.1 mm)
Form Factor	Slide	Clamshell	Clamshell
Antenna	Internal	Internal	Internal
Battery Life	Talk: 3 hr Standby: 250 hr (10.4 days)	Talk: 3.5 hr Standby: 398 hr (16.6 days)	Talk: 5 hr Standby: 240 hr (10 days)
Display	LCD (Color TFT/TFD) Colors: 262,144 (18-bit) 176 x 220 pixels	LCD (Color TFT/TFD) Colors: 65,536 (16-bit) 176 x 220 pixels	LCD (Color STN) Colors: 262,144 (18-bit) 128 x 160 pixels
Platform / OS	(proprietary)	(proprietary)	(proprietary)
Memory	50 MB	55 MB	4 MB
Phone Book Capacity	1000	500	shared memory
	Samsung SGH-A737 / SGH-A736	LG CU515	Nokia 6085 / 6086
Features
Accessibility
Digital TTY/TDD	Yes	Yes	Yes
Hearing Aid Compatible	Yes M3, T3 (mostly tele-coil compatible)	Yes M3, T3 (mostly tele-coil compatible)	Yes * M3, T3 (mostly tele-coil compatible)
Multiple Languages	Yes	Yes	Yes *
Alerts
External Display	-	Yes	Yes
Polyphonic Ringtones	Yes	Yes	Yes
Ringer Profiles	Yes	-	Yes
Vibrate	Yes	Yes	Yes
Connectivity
Bluetooth	Yes	Yes	Yes
PC Sync	-	-	Yes
USB	Yes	Yes	Yes
Contacts
Multiple Numbers per Name	Yes	Yes	Yes
Picture ID	Yes	Yes	Yes
Ringer ID	Yes	Yes	Yes
Voice Dialing	-	-	Yes Speaker-independent (automatic)
Customization
Custom Graphics	Yes	Yes	Yes
Custom Ringtones	Yes	Yes	Yes
Real-Music Ringers	Yes	Yes	Yes
Data & Network
Data-Capable	Yes	Yes	Yes
Flight Mode	Yes	Yes	-
Packet Data	Yes HSDPA 1.8	Yes HSDPA 3.6	Yes EDGE
UMA	-	-	Yes *
WAP / Web Browser	Yes	Yes	Yes
Input
Predictive Text Entry	Yes	Yes	Yes
Side Keys	Yes	Yes	Yes
Memory
Memory Card Slot	Yes microSD (TransFlash)	Yes microSD (TransFlash)	Yes microSD (TransFlash)
Messaging
Email Client	Yes	Yes	Yes
MMS	Yes	Yes	Yes
Text Messaging	Yes	Yes	Yes
Text Messaging Templates	Yes	Yes	Yes
Music
FM Radio	-	-	Yes
Music Player	Yes	Yes	Yes
Photo & Video
Camera	Yes 1+ megapixel	Yes 1+ megapixel	Yes VGA (640 x 480)
Streaming Video	Yes	Yes	Yes
Video Capture	Yes	Yes	Yes
Video Sharing	Yes	Yes	-
Productivity
Alarm	Yes	Yes	Yes
Calculator	Yes	Yes	Yes
Calendar	Yes	Yes	Yes
SyncML	-	-	Yes
To-Do List	Yes	Yes	Yes
Voice Memo	Yes	Yes	Yes
Software
Games	Yes	Yes	Yes
Java (J2ME)	Yes	Yes	Yes
Voice
Push-To-Talk	-	Yes	Yes *
Speaker Phone	Yes	Yes	Yes
	* Some versions only
	Samsung SGH-A737 / SGH-A736	LG CU515	Nokia 6085 / 6086

NOTE: Differences are highlighted with bold / black text for visual clarity only.

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Leopard Server Part 1 – Server Styles

After the longest wait in the history of Mac OS X, Leopard has finally arrived!

In years past we’ve done one monster article covering all of the new bits in server. Every year, as OS X Server got bigger, the article got harder and harder to do. At the same time, as OS X Server got better and better, we’ve had less and less time to do the monster article since we’ve all been snowed in at our day jobs as more and more people have implemented OS X Server.

So, to celebrate the release of Leopard Server we’ve broken up the monster article into a series of them covering the gamut from installation to administration and printing to Podcast Producer. Read on for our first part of this series on what “style” of server to pick.

Overall we’ve got to say we’re quite impressed with Leopard Server. In particular the renewed focus on it being a server for the little people. There was much nashing of teeth when the original OS X Server came out that the carefree days of AppleShare IP were over and Mac admins were going to have to put on their big admin undies and learn Unix.

OS X Server struggled with being all things to all people. Attempting to be a big-iron Unix server at the same time as supporting a 15-person graphic design shop without an IT department is a hard task, and one that was not always carried off with great distinction.

To that end server now has the Server Preferences application which distills much of the management operations into a few simple tasks. It keeps you into a clearly defined area that allows you to utilize a lot of the functionality while keeping the buttons and boxes to a bare minimum. Perfect for the part-time admin or the full-time something else that still has to run a server.

This is a marked change from earlier versions of server, and the installation method has changed to support this.

One Server becomes three servers

When installing Leopard Server for the first time you’ll be presented with the option of three different “styles”:

Standard
Workgroup
Advanced

Each choice has advantages and disadvantages, along with some assumptions and pre-requisites about the existing infrastructure. Let’s break down each option so you know which one is the right choice for your environment.

Services Available By Default

Standard
File, Mail, Backup, Calendar, Web, Instant Messaging, Remote Access (VPN)

Workgroup
File, Backup, Calendar, Web, Instant Messaging

Advanced
File, Mail, Backup, Calendar, Web, Instant Messaging, Remote Access (VPN), Podcasting, Clustering, Management, Networking, Directory Services, System Imaging

Assumptions

Standard
The first (or only) server in a small organization, all services setup automatically, all client machines, when bound to the server will be setup automatically.

Workgroup
Uses existing user accounts (requires existing Directory service and DNS server), all client machines, when bound to the server will be setup automatically. The server is going into an environment with other servers and services already in place and running.

Advanced
No assumptions on, or prerequisites for, existing infrastructure. Manage and control multiple servers, thousands of users, groups and computers, setup network home folders and mobile users, save setup details for automated configuration of multiple servers, upgrade existing servers (it is not possible to upgrade an Tiger server to a Leopard Standard or Workgroup Server)

Management done through:

Standard
Server preferences for all services*, users and groups

Workgroup
Server preferences for all services*, users and groups

Advanced
Server Admin, Workgroup Manager and command line tools

*When opening Server Admin on Leopard Standard or Workgroup servers you will be presented with three options: (1) Back out and use the recommended Server Preferences application, (2) use Server Admin for a one-off change not available in the Server Preferences GUI, or (3) convert the server into an Advanced Server (this is a one-way process, so make sure you really want to do it before going advanced).

Limitations

Standard
Everything is setup automatically, with assumptions that there won’t be hundreds of users, or multiple servers, so if expansion is a possibility, it may be easier to start with a different configuration

Workgroup
You need to have good, working DNS and an existing Directory Service (whether it be LDAP-based or Active Directory based). If that goes away your server is going to need some TLC to get things running again.

Advanced
None – let your hair down and go for it.

What Services are available?

Some services aren’t available or configuarable in certain server setups, so it’s a great idea to check the list below and see what’s used when:

Service 					Standard 	Workgroup 	Advanced 

File sharing (AFP and SMB protocols) 	        Included 	Optional 	Optional
File sharing (FTP and NFS protocols) 	        Not used 	Not used 	Optional
Printer sharing (USB or FireWire printer) 	Automatic 	Automatic 	Not used
Print 					        Not used 	Not used 	Optional
iCal (calendar sharing, event scheduling) 	Included 	Optional 	Optional
iChat (instant messaging) 			Included 	Optional 	Optional
Mail with spam and virus filtering 		Included 	Optional 	Optional
Web (wikis, blogs, webmail) 		        Included 	Optional 	Optional
VPN (secure remote access) 			Optional 	Optional 	Optional
Internet gateway (NAT, DNS) 		        Optional 	Optional 	Optional
Time Machine backup of server 		        Optional 	Optional 	Not used
Open Directory (user accounts and other data) 	Automatic 	Automatic 	Optional
Application firewall 				Optional 	Optional 	Not used
IP firewall with optional adaptive firewall 	Not used	Not used 	Optional
Podcast Producer 			        Not used 	Not used 	Optional
Comprehensive user and workgroup management 	Not used 	Not used 	Optional
Xgrid (computational clustering) 		Not used 	Not used 	Optional
DHCP, DNS, NAT 					Automatic 	Automatic 	Optional
RADIUS 					        Not used 	Not used 	Optional
NetBoot and NetInstall (system imaging) 	Not used 	Not used 	Optional
Spotlight (searching) 				Automatic 	Automatic 	Automatic
QuickTime Streaming 				Not used 	Not used 	Optional
Software update 				Not used 	Not used 	Optional
Remote management 				Included 	Included 	Included
Remote login (SSH) 				Included 	Included 	Included

So… which one is right for you?

If you fancy yourself a seasoned admin you probably have the urge to head straight to the Advanced option and never think about this again. For the most part, you’ll do fine doing that. We’ll talk about the exception to this in the next article in the series covering the changes to directory services in Leopard.

If you’ve never used a server before, the Standard config has an awful lot of appeal. Calling it a “server with training wheels” is a bit derogatory, but the analogy isn’t entirely negative. The Standard and Workgroup configs are designed to keep your knees from getting skinned. And when you’re coming back from a late night out the training wheels are going to help keep you from going off the road and into the weeds.

Have fun playing around with Leopard Server and catch us later for the next in the series.

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Comcast Offers Super-Fast Internet Speeds

Comcast is launching a new premium service that offers download speeds starting at 50 mbps.

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Message received: This Wi-Fi router from Intel uses specialized software to send data to a receiving radio more than 60 miles away. The goal is to connect sparsely populated rural areas with urban cores. Credit: Intel

Intel has announced plans to sell a specialized Wi-Fi platform later this year that can send data from a city to outlying rural areas tens of miles away, connecting sparsely populated villages to the Internet. The wireless technology, called the rural connectivity platform (RCP), will be helpful to computer-equipped students in poor countries, says Jeff Galinovsky, a senior platform manager at Intel. And the data rates are high enough–up to about 6.5 megabits per second–that the connection could be used for video conferencing and telemedicine, he says.

The RCP, which essentially consists of a processor, radios, specialized software, and an antenna, is an appealing way to connect remote areas that otherwise would go without the Internet, says Galinovsky. Wireless satellite connections are expensive, he points out. And it’s impractical to wire up some villages in Asian and African countries. “You can’t lay cable,” he says. “It’s difficult, expensive, and someone is going to pull it up out of the ground to sell it.”

Already, Intel has installed and tested the hardware in India, Panama, Vietnam, and South Africa. Later this year, the company will sell the device in India, with a target price below $500. The point-to-point technology will require two nodes, which could provide “full back-end infrastructure” for less than $1,000, Galinovsky says.

One node is usually installed at the edge of an urban area, wired to a local-area network cable, he explains. Using a directional antenna, the device shoots data to a receiving antenna as far as 60 miles away. Any farther away, and the system encounters problems due to the curvature of the earth. Practically, most links will be set up less than 30 miles away from one another. Once a node is installed in a village, the connection can be dispersed using standard cables and wireless routers, Galinovsky says.

There is nothing particularly innovative in the antenna technology and the router hardware, he says. The trick, he explains, comes in the software that the radios use to communicate with each other. “If you take standard Wi-Fi and focus it,” Galinovsky says, “you can’t get past a few kilometers.” The reason is that one radio will send out data and wait for an acknowledgment from the other radio that the data was received. If the transmitting radio doesn’t receive the acknowledgment in a certain amount of time, it will assume that the data was lost, and it will resend it.

Intel’s RCP platform rewrites the communication rules of Wi-Fi radios. Galinvosky explains that the software creates specific time slots in which each of the two radios listens and talks, so there’s no extra data being sent confirming transmissions. “We’re not taking up all the bandwidth waiting for acknowledgments,” he says. Since there is an inherent trade-off between the amount of available bandwidth and the distance that a signal can travel, the more bandwidth is available, the farther a signal can travel. (See a video with a technical explanation of the RCP here.)

Importantly, the devices require relatively little power. Running two or three radios in a link, Galinvosky says, requires about five to six watts. This makes it possible to power the radios using solar energy.

The Intel project and forthcoming product “sound like a huge step forward” in terms of usable bandwidth over long-range lengths, says Deborah Estrin, professor of computer science at the University of California, Los Angeles. Estrin develops technology for sensor networks in remote areas that monitor seismic activity, among other things. She says that these sensors are spread out over large areas and need to transmit large amounts of data. Previous low-power, inexpensive wireless communication technologies could only stretch a few kilometers, she says. “What’s important is that Intel is getting much longer distances.”

Galinvosky says that the RCP is alluring to markets beyond India. “We’re seeing a lot of interest in the industry,” he says. “Every time we talk about this, they say, ‘We need this yesterday.’”

Comments

• Video is very helpful – 2 sets of Wi-Fi are used nekote on 03/18/2008 at 8:31 AM

  Comments: 93 Avg Rating:

  The video: http://blogs.intel.com/research/2008/03/rural_connectivity_platform_be.php Was very helpful. This web article photo does *NOT* show the point-to-point directional dish antenna, rather just the 2 standard Wi-Fi antennas, giving a mis-leading initial impression. There are 2 distinct Wi-Fi “networks” – the point-to-point directional long distance link and the more familiar area Wi-Fi Access Point. Quite a while ago, various “hacker” communities achieved such long distances without even altering the Wi-Fi protocol, using directional parabolic antennas (eg: http://www.usbwifi.orcon.net.nz/) Would seem even higher bandwidth could be achieved by having full duplex continuous transmissions (using different send / receive frequencies?  using 2 separate directional parabolic anntennas, one for send, one for receive?).  Of course, there’d be an opportunity to improve the protocol, possibly using some sort of large (MBs?) sliding transmit / acknowledge window that also re-sent individual missed packets (“holes”). Rate this comment: (Reply)

• 	oldi idea demarco on 03/18/2008 at 9:02 PM
  Comments: 3 Avg Rating:	This product uses an old idea (ACK timing)which has been implemented in many software product, such as RouterOS form Mikrotik. The true novelty is the introduction of a TDMA-like frame in a CSMA protocol. I ask myself if this product will host also mesh capabilities. If yes, a true low cost urban mesh network will possible. Rate this comment: (Reply)

  • Re: oldi idea makevuy on 03/19/2008 at 2:48 AM

    Comments: 1 Avg Rating:

    In Essence the original idea was developed for research group DGP (Kampur, India) http://www.cse.iitk.ac.in/users/braman/dgp.html#dgppubs. On the other hand I don’t know if this solution is capable to implement PtMp links in infraestructure mode. Finally I don’t know if will be possible to get quality of service….because this solution only improve the throughput but I don’t know if can get differentiation between classes of traffic very important in the case of using VoIP or IP video. Sandra. Thanks! Rate this comment: (Reply)

  • 	Re: oldi idea METRA on 03/25/2008 at 4:08 PM
    Comments: 1	Demarco, Could you please elaborate on the reason why you think this system would be good for mesh WMAN?  I’m asking because if this product is capable of a mesh topology setup then it would really come in very handy on a couple of projects I’m working on.  I just don’t have all the specs on this product just yet. Thanks Rate this comment: (Reply)

• 	Latency rfwrangler on 03/20/2008 at 3:37 PM
  Comments: 1 Avg Rating:	I am interested in the latency issues that would be had over distances described.  This would be a factor for VoIP and Video transmissions as well.  They already address this in the description in the fact that the time-out is reached with regular Wi-Fi equipment.  Continuous send/receive signals would help this but there would still be a latency issue. Rate this comment: (Reply)

  • 	Re: Latency wirelesh on 04/03/2008 at 4:10 PM
    Comments: 1	The only alternative for voice communications in many places where this could be used is satellite.  Talk about latency!  I don’t think 100 km is a concern. Rate this comment: (Reply)

• 	alternative wifi aryawidura on 03/22/2008 at 6:23 AM
  Comments: 1 Avg Rating:	It will become alternative wifi device in my country, im interesting to test this device if its already launch Rate this comment: (Reply)

Long-range Wi-Fi

From Wikipedia, the free encyclopedia

Main article: Wi-Fi

Long-range Wi-Fi is used for low-cost, unregulated point-to-point connections, as an alternative to cellular networks, microwave or satellite links. The use of the term “long range wifi” as depicted on this page for extreme ranges is not in any way endorsed by the Wi-Fi Alliance and is not in any way tested or certified by the Wi-Fi Alliance for interoperability or performance.

//

[edit] Introduction

Since the development of the Wi-Fi radio standard, great leaps in the technology’s abilities have been made. In one area, range, Wi-Fi has been pushed to an extreme, and both commercial and residential applications of this Long Range Wi-Fi have cropped up around the world. It has also been used in experimental trials in the developing world to link communities separated by difficult geography with little or no connectivity options.

[edit] Applications

[edit] Business

• Provide coverage to a large office or business complex or campus.
• Establish point-to-point link between large skyscrapers or other office buildings.
• Bring Internet to remote construction sites or research labs.

[edit] Residential

• Bring Internet to a home if regular cable/DSL cannot be hooked up at the location.
• Bring Internet to a vacation home or cottage on a remote mountain or on a lake.
• Bring Internet to a yacht or large sea-faring vessel.
• Share a neighborhood Wi-Fi network.

[edit] Large-scale deployments

The Technology and Infrastructure for Emerging Regions (TIER) project at University of California at Berkeley, in collaboration with Intel, utilizes a modified Wi-Fi setup to create long-distance point-to-point links for several of its development projects in the developing world. This technique, dubbed Wi-Fi over Long Distance (WiLD), is used to connect the Aravind Eye Hospital with several outlying clinics in Tamil Nadu state, India. Distances range from five to over fifteen kilometers with stations placed in line of sight of each other. These links allow specialists at the hospital to communicate with nurses and patients at the clinics through video conferencing. If the patient needs further examination or care, a hospital appointment can then be scheduled. Another network in Ghana links the University of Ghana, Legon campus to its remote campuses at the Korle bu Medical School and the City campus; a further extension will feature links up to 80km apart.

[edit] Increasing range in other ways

See also 802.11 non-standard equipment

[edit] Specialized Wi-Fi channels

In most standard Wi-Fi routers, the three standards, A, B and G, are enough. But in long-range Wi-Fi, special technologies are used to get the most out of a Wi-Fi connection. The 802.11-2007 standard adds 10 MHz and 5 MHz OFDM modes to the 802.11a standard, and extend the time of cyclic prefix protection from 0.8 µs to 3.2 µs, quadrupling the multipath distortion protection. Some commonly available 802.11a/g chipsets support the OFDM ‘half-clocking’ and ‘quarter-clocking’ that is in the 2007 standard, and 4.9 GHz and 5.0 GHz products are available with 10 MHz and 5 MHz channel bandwidths. It is likely that some 802.11n D.20 chipsets will also support ‘half-clocking’ for use in 10 MHz channel bandwidths, and at double the range of the 802.11n standard.

[edit] 802.11n (MIMO)

Preliminary 802.11n working became available in many routers in 2008. This technology works by using multiple antennas to target one or more sources to increase speed. In tests, the speed increase was said to only occur over short distances rather than the long range needed for most point to point setups.^[1]

[edit] Power increase or receiver sensitivity boosting

A rooftop 1 Watt WiFi amp,feeding a simple antenna

Another way of adding range uses a power amplifier. Commonly known as “range extender amplifiers” these small devices supply usually around ½ watt of power to the antenna. Such amplifiers may give more than 5x the range to an existing network. Each 6dB gain doubles range, and in the case of the popular Linksys WRT54G The RadioLabs 2.4 GHZ range extender amplifier this increases the stock power of the WRT54G from +18dBm (63 mW) to +27dBm (500 mW), a 9dB (8x) increase – enough for perhaps tripling the range.^[2] These power amplifiers offer a tempting enhancement that can easily be added to existing networks in places where law allows. Aside from legal issues (significant in some countries),they however may cause interference and channel swamping to other WiFi users. The alternative techniques of selecting a more sensitive WLAN adapter (some are quite “deaf”)and more directive antenna should hence be initially considered.

[edit] Higher gain antennas and adapter placement

Specially shaped antennas can be used to increase the range of a Wi-Fi transmission without a drastic increase in transmission power. High gain antenna may be of many designs,but all allow transmitting a narrow signal beam over distances of several kilometers,usefully often nulling out nearby interference sources. A popular low-cost home made approach increases WiFi ranges by just placing standard USB WLAN hardware at the focal point of modified parabolic cookware (see “www.usbwifi.orcon.net.nz/rvwifi.jpg”). Such “WokFi” techniques typically yield gains of 12-15dB over the bare system- enough for line of sight (LOS) ranges of several km and improvements in marginal locations. N.B. Although often low power,cheap USB WLAN adapters suit site auditing and location of local signal “sweet spots”. As USB leads incur none of the losses normally associated with costly microwave coax & SMA fittings,just extending a USB adapter (or AP etc) up to a window,or away from shielding metal work and vegetation,may dramatically improve the link.(See “www.usbwifi.orcon.net.nz/wifiledge.jpg”)

[edit] Protocol hacking

The standard 802.11 protocol stacks can also be modified to make them more suitable for long distance, point-to-point usage, at the risk of breaking interoperability with other Wi-Fi devices and suffering interference from transmitters located near the antenna. These approaches are used by the TIER project (see “Rethinking Wireless in the Developing World”).

[edit] Obstacles to long-range Wi-Fi

Methods that stretch the range of a Wi-Fi connection may also make it fragile and volatile, due to mundane problems including:

[edit] Landscape interference

Obstacles are among the biggest problems when setting up a long-range Wi-Fi. Trees and forests degrade the microwave signal, and rolling hills make it difficult to establish line-of-sight propagation.

In a city, buildings will impact integrity, speed and connectivity. Steel frames partly reflect radio signals, and concrete or plaster walls absorb microwave signals significantly, but sheet metal in walls or roofs may efficiently reflect Wi-Fi signals, causing an almost total loss of signal.

[edit] 2.4 GHz interference

Microwave ovens in residences dominate the 2.4 GHz band and will cause “meal time perturbations” of the noise floor. There are literally hundreds of other sources of interference that aggregate into a formidable obstacle to enabling long range use in occupied areas: baby monitors, wireless cameras, remote car starters, DECT and residential wireless phones, Bluetooth products to name just a few.

Phones

Many cordless phones in the US and Canada use the 2.4GHz frequency, the same frequency at which Wi-Fi standards b, g and n operate. This can cause a significant decrease in speed, or sometimes the total blocking of the Wi-Fi signal when a conversation on the phone takes place. There are several ways to avoid this though, some simple, and some more complicated.

• Buy/Use wired phones.
• Buy 5.8GHz or 900MHz phones, commonly available today.
• Use VoIP/WiFi phones; these share the WiFi base stations and participate in the WiFi contention protocols.
• Test several different Wi-Fi channels to avoid the phone channels.

The last will sometimes not be successful, as numerous cordless phones use a feature called Digital Spread Spectrum. This technology was designed to ward off eavesdroppers, but the phone will change channels at random, leaving no Wi-Fi channel safe from phone interference.

Car alarms

Certain car manufacturers use the 2.4GHz frequency for their car alarm internal movement sensors. These devices broadcast on 2.45GHz (between channels 8 and 9) at a strength of 500mW. Because of channel overlap, this will cause problems for channels 6 and 11 which are commonly used default channels for Wi-Fi connections. Because the signal is transmitted as a continuous tone, it causes particular problems for Wi-Fi traffic. This can be clearly seen with spectrum analysers.

[edit] Longest unamplified Wi-Fi link

279 km Wifi link with DD-WRT and openwrt Read here

Achieved by: Fundación Escuela Latinoamericana de Redes, Latin American Networking School

[edit] Abstract

• Pico del Águila- El Baúl Link.
• Central frequency: 2412 MHz
• IEE 802.11 (Wi-Fi), channel 1, 22 MHz. bandwidth
• Wireless routers: Linksys WRT54G, OPEN-WRT firmware at el Águila and DD-WRT firmware at El Baúl.
• Length: 279 km.
• Parabolic dish antennas were used at both ends, recycled from satellite service.
• At El Aguila site an aluminum mesh reflector 2,74 m diameter, center fed, at el Baúl a fiberglass solid reflector, offset fed, 2,4 x 2,74 m. At both ends the feeds were 12 dBi Yagis.
• Linksys WRT54g routers fed the e antennas with short LMR400 cables, so the effective gain of the complete antenna is estimated at about 30 dBi.
• As far as we know, this is the longest range attained with this technology, improving on a previous US record of 125 miles achieved last year in U.S. The Swedish space agency attained 310 km but using 6 watt amplifiers to reach an overhead stratospheric balloon

[edit] References