Accomack County / National Weather Service
EMWIN retransmission system (ACER) is now up and running.
It is transmitted from an antenna 350' high
on the Mappsville, Virginia tower with a EIRP of 800 watts.
The frequency is 163.350 Mhz and is the first
in Virginia to use a NOAA assigned EMWIN frequency.
This signal can be received from Vienna, Maryland
to Virginia Beach, Virginia.
The data rate is 1200 baud and, in time will
be upgraded to 9600 baud to carry even more products.
See coverage map below.
Please read the below to learn how to receive
and use this data.
WeatherDirect is National Weather Service information
that is constantly updated on a 24 hour basis.
The service is public information and is free.
The signal originates at the Weather Service Headquarters
in Silver Spring, Maryland. It is uplinked to GOES satellites from
the transmission site in Wallops Island, Virginia. The
signal is encoded and modulated for satellite broadcast with equipment
developed by Zephyrus.
The Weather Service designation for the data is "EMWIN",
which stands for "Emergency Managers Weather Information
Network ". The information is distributed as a signal
that allows your personal computer to become a graphics, data, and
alarm terminal.
With appropriate free "Windows" software, the information
is displayed in both text and graphical form. It includes:
Software settings permit selection of items to be
automatically printed as they are received. As a bonus, the WX-12 receiver
also provides a
WEFAX output for live reception of satellite picture
of weather systems.
Tulsa based Zephyrus Electronics is the pioneer in development
of low-cost satellite data broadcast equipment. Design and
production of receiving equipment for the WeatherDirect
/ EMWIN signal is a natural application of that technology. The
GOES satellites are received with Zephyrus WX-12 or WX-13
systems. Installation is normally done by the user and typically
takes less than one hour to complete.
In some areas, the Emwin signal is recovered from satellite
and retransmitted by FM SCA subcarriers, or by way of a
stand-alone VHF signal. Using Zephyrus equipment, VHF
signals are now being broadcast at 9600 baud. This is done using a
similar technique we provided to the National Weather
Service to put the 9600 baud signal on the GOES satellites.
Local retransmission operators can replace data that is
trivial to their particular location with information gathered from other
sources. This is accomplished with a dedicated computer
using "retransmission engine" software. Local transmissions at 1200
baud rate must use the retransmission software to parse
selected data of local interest from the 9600 baud satellite
transmission.
To find out more or order your EMWIN receive system called "Weather Direct" Click Here
Weather
NODE Ver. 4 (Free)
RealEMWIN
InterWARN
WxMessage
Weather
NODE Ver. 4 Software Source Code
1, Signal easy to receive, a simple outside antenna will do.
2, Signal may be received with a 4 dB gain outside antenna mounted
at least 20' high.
3, Signal may be received with a 8 dB gain beam outside antenna
mounted at least 50' high.
Tuned to 163.350 Mhz
Impedance 54 Ohms
VSWR 1.2 to 1
J Factor -8
Forward Gain: 9.8 dB
F/B Ratio: 19 dB
H Plane Beamwidth: 60 Degrees
Connector Type: UHF (PL-259)
Tuned by Dennis Cope
Cushcraft 124WB beam 2 meter yagi antenna is modified to receive EMWIN
on 163.350 Mhz by
trimming 51mm from the ends of each element. A tubing cutter should
be used to slightly bevel the
element ends to reduce the end capacitive effect.
The “T” match is tuned to achieve the best swr and impedance match
possible. I found by moving
the matching straps 134 mm, measured from the inside edge of the matching
straps to the end of the
screw end of the rod.
As per the Cushcraft antenna engineer, no changes were necessary with
the element spacing and the
F/B ratio and H plane beamwidth would not be changed. Stacking
is still possible but the “E” plane
spacing would be 70". “H” plane spacing would be 54".
By retuning this antenna allows you to receive EMWIN without having
to purchase a more expensive
commercial antenna for the NOAA EMWIN frequencies. The
antenna has been used in the field and
works great. Down lead (coax) should be 9913F-7, this cable has
about 1.4 dB loss per 100' at 100Mhz
but RG-213 will work well also.
The Cushcraft 124WB and coax can be purchased from Ham Radio Outlet
"HRO" price is $69.95 plus shipping.
The cable (RG-213) 100' complete with PL-291 connectors is $56.00
plus shipping and the receiver adapter (UB312)
is $7.00.
HRO's phone number is 800-444-4799.
EMWIN Links
EMWIN Software and More Information
