EMWIN
(Emergency Management
Weather Information Network)
Overview -
EMWIN started around
1996 as a method to disseminate weather data outside of traditional
channels. Typically weather data were distributed through
weather wire or the domestic data service. These services were
expensive and only available to larger universities, government, and private
enterprise. Additionally, those receiving the service were not
allowed to rebroadcast, even to pagers.
Towards 1996 a move
started among the weather community and the National Weather Service
to develop a system that would be accessible by a greater number of
people. Hence, the birth of EMWIN. Over the past several
years, EMWIN has attracted a great following and continues to
expand.
There are four
primary methods of receiving EMWIN data. The first is through
GOES 8 and/or GOES 10 downlinks. These are satellites that are
in geostationary orbit, about 36,000 km from Earth. These data
are uplinked to the satellites from the NWS and then to receivers back
on Earth. The next method is through EMWIN retransmission
sites that are surface based. These sites may receive multiple
feeds, but typically use satellite as their primary feed. The
feed is then retransmitted via 150-168 MHz frequency range.
The speed varies from 1200 baud to 9600 baud. The third feed
is called Byte Blaster and is accessible via the Internet.
Internet servers hosting Byte Blaster software allow clients to
connect and then serve data to them. The final feed and
slowest is File Transfer Protocol (FTP), which is also accessible
through the Internet.
The best part is that
the data (signal) are free. You only need pay for the
equipment and that is it.
Getting the feed -
Hardware:
Satellite - All you need is a satellite dish, receiver, downlink,
and computer. This is the most expensive option, as the
satellite equipment alone is around $700. However, it allows
the most flexibility.
Retransmit - For those that are in range of a retransmit site, this
is a viable option. You need a computer, VHF antenna, and
receiver (demodulator). Make sure that you confirm what speed
the feed is, there may be multiple feeds in your area.
Byte Blaster - This requires a stable Internet connection and of
course a computer.
FTP - Same as Byte Blaster
Software:
All the above options require software. In the early days the
primary software was produced by Zenocode called Weather Node.
This company is out of business, however two people have picked up
where they left off. Software is readily affordable, ranging
from $20 to $70.
Reference -
General:
NWS EMWIN Site
Hardware:
Zephryus
Tigertronics
Software:
Real EWMIN
Weather
Message
