AMRAD SkyWarn Support

It is time to advance the state of the art in Amateur Radio's support of the National Weather Service's SkyWarn program.

Current Practice

An Amateur Radio Station located at the NWS Office provides relay between SkyWarn Spotters and NWS Forecasters via VHF and UHF FM voice. The station also provides emergency communication between NWS forecast centers accross the country via HF SSB voice. Some sites have a terminal and TNC to do 1200 baud AX.25 packet.

In the Washington, DC area we can receive a tremendous amount of weather data via radio.

Present Challenge

Distribute AFOS over Amateur TCP/IP Packet. Currently under development is a gateway between the NWS computer network and the Amateur Radio packet network in Iowa. (Contact kd9kx@rf.org for details.) Amateur Radio operators who can access the amateur TCP/IP network (net 44.x.x.x IP addresses) can use standard internet techniques such as ftp, finger, nntp and http to access NWS bulletins.

More effective means of digital data dissemination needs to be made available to amateurs who participate in weather nets.

Future Goals

Two-way digital messaging.

SkyWarn spotter reports are routed in digital form from the point of observation to the nearest NWS office.

More research and development needs to be done to improve the robustness of communication. The present NWS data broadcast methods are highly susceptable to noise corruption, and the 1200 baud data rate now in use could stand improvements *if* reliability and coverage are maintained.

AMRAD Contributions

BayPac Modem modification

Terry Fox, wb4jfi, has modified his BayPac BP-1 Packet modem to receive EMWIN data. The mod is two resistors and a transistor to invert the signal and put it onto pin 3. Apparently the packet software gets its data from CTS, so this mod does not interfere with the normal operation in packet mode.

He had the audio of his scanner split, and one feed into a BayPac to the MRC software running on a laptop, and the other feeding the MRC demodulator to MRC software on what is often the AMRAD BBS. Both systems were clicking along. The BayPac would occasionally miss a packet that the MRC got, but that happened less frequently after removing the scope probes from the BayPac circuit. Might be improved by taking the Break-Out-Box out from between the BayPack and the port.

EMWIN software for Unix

Maitland Bottoms, aa4hs, has written support software for handling the EMWIN data as broadcast. So far emwin decodes the serial data stream into files. The text files can be looked at directly with more. The Satellite Image files can be viewed with the help of sattopgm. The other graphics files can be parsed with utf. Display via BSD Unix plot and the commonly available X11 Window System should be available soon. For now, you may take a look at the BETA Code. (Note: this stuff is getting old. I am readying a new for 1998 version. It will be in a file called 400.175.tar.gz to reflect the new frequency used by the NWS transmitter.)

Note that the BETA Code includes a LaTeX version of the documentation for the National Weather Services "Universal Transmission Format". Maybe you want to just get the PostScript UTF Documentation file.

The current plan is to utilize the "Soundcard Modem" features of recent Linux kernels (standard in 2.0.35 now!), increasing the number of users who already have the right hardware to receive the data. Just plug the audio from your scanner into your soundcard.

The good stuff, including example setup scripts, will be provided in a .deb file form to drop in to Debian Linux systems. See the EMWIN Debian package page for more info. Also check this site for some files.

An Emwin-developers mailing list is available to coordinate improvement to the software.

How's my UTF stuff working? See example GPH files converted to PostScript and portable network graphics files.

Back to AMRAD Home Page

Feel free to contact me.

aa4hs@amrad.org

Last modified: Sat Mar 4 08:18:14 CST 2000