forgive me, DD was from 1995
hardly worth our time to
discuss any further. I'll try
to dig up something more
recent before Tuesday AM.
here's some competative tidbits from March'98
HIGH BANDWIDTH AND HIGH MOBILITY?
One of the more difficult headaches regarding on-location cybercasts is the conflicting need for
high- speed bandwidth (at least 384 Kbps and preferably T-1 speeds) deliverable to an
encoding PC. However, high-speed leased lines are a pain in the neck to extend from a building
demarc (a demarcation point- where the local phone company brings its copper and fiber into
the building) to an event site. For open air events, such as concerts, stringing long lengths of
copper wire between the nearest demarc and a cybercast encoding site may be horrifically
expensive and impractical. Not to mention the line quality problems associated with hauling that
much copper around. At that point it is copper, regardless of how the phone company gets
signal to the demarc.
Cybercasters have come up with some interesting strategies to get around the "last 100 yards"
problem. Itv.net (www.itv.net) has used short-haul laser links to establish virtual links between
locations in place where there is line of site between two points. One laser "modem" is installed
within convenient wire distance of the demarc and sends/receives data from the second laser,
typically sitting almost on top of the video encoding setup.
Lasers are nice if you have line of sight, but most folks aren't that lucky and a set of this gear can
set you back $10,000 without breaking a sweat. Not to mention problems in rain and its high
power demands (120v AC required; no batteries here).
The next step is short-distance wireless LANs. I'm not talking about a $10,000 dedicated
directed antenna that allows you to get a T-1 worth of bandwidth up to seven miles away, but
lower power products that are designed for in-building use. For example, we were very
successful using a 2 GHz spread-spectrum product by BreezeCom (www.breezecom.com) that
consisted of a pair of game-cartridge sized "bricks" with a pair of three-inch high antennas, later
supplemented by a third PC card transmitter. The bricks operated as a pass-through Ethernet.
One brick plugged into a 10baseT outlet and its power supply plugged into a power strip. The
other brick was taking to the appropriate location, powered up, and took a 10BaseT connection
from the computer. The PC card acted as a wireless Ethernet card and didn't require external
power. A pair of bricks with the basic antennas cost around $1,500, while the PC card was
under $500 at the time we purchased it. Today's prices are probably much more friendly.
Operationally, the 2 GHz spread-spectrum gear acted as a transparent Ethernet moving at
around 1- 2Mbps per second at distances of around 80 to 100 meters indoors in heavy clutter.
A computer room and lots of office cubes, as well as several walls, sat between the two devices
and no attempt was made to optimize their positioning. We would have tested for longer
distances but we ran out of room in the building.
Such wireless spread-spectrum equipment gives useful reach with minimal headaches for either
in- building extensions or stadium extensions. Longer distances can be reached through the use
of larger antennas and the proper positioning of equipment. While line of sight is not necessary
for these products to work, it can help in marginal situations.
Two other products can also be used for lower-speed (i.e. non-video) connections. Digital
Equipment Corporation makes a plug and play 900 MHz cordless modem
(www.networks.digital.com/dr/npg/deiap- mn.html). A base unit plugs into a standard telephone
line while the roamer part is slapped onto the back of a laptop. The unit has impressive range;
I've seen them operate between buildings without breaking a sweat.
In some cities, the Metrocom Ricochet system (www.ricochet.net) is available. Under most
conditions, Ricochet will perform between 14.4 Kbps and 28.8 Kbps, but there are limitations
on coverage and higher data rates. Ricochet depends on hundreds of smaller relay nodes bolted
to light poles. If you're out of range of the network, you're out of luck.
More products should become available this year. Sprint PCS was making noises about 128
Kbps/ISDN speed devices and the LEO satellite crowd will have a couple of expensive options
for data communications. However, LEO satellite communication will also offer unprecedented
flexibility for those who can afford it. Instead of many large suitcases of satellite communications
equipment, Internet broadcasters will be able to roam the world for stories - assuming they can
find someone to recharge their batteries at the end of the day. |
