WX.TXT USING APRS IN WEATHER AND SKYWARN APPLICATIONS Document version: 8.6.7 26 Jul 2004. (Previous was 8.3.5 of 10 Mar 99 Author(s): Bob Bruninga, WB4APR ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ New: Putting raw PEET Bros WX packets on the air is no longer encouraged. It is better to use one of the little PIC's to convert to standard APRS format so that all the Mobiles and HAM HUD's can see the WX New in 809 Now supports COUNTY WX Warnings. See sections below New in 796 Supports HC/TS winds to the DOT symbol too for predicts New in 793 ***** All new WX formats not Backward compatible ***** WX-GETmetar can load METAR data from a file into P-LIST. New in 78b File-Print will log new data to a printer and on the P-LIST, Just-Print-WX will print a file or page of all WX data Fixes receipt of remote Ultimeter WX data for some units OVERVIEW: APRS is an ideal tool for reporting weather conditions via packet when its second serial port is connected to a PEET Bros ULTIMETER or DAVIS home weather station. APRS is idealy suited for SKYWARN with the following features: MAP DISPLAY - Shows the location of all WX stations and WX objects WX SYMBOLS - Dozens of WX symbols that will even move if given a CSE/SPD WX WARNINGS - You can mark large areas with either rectangles, circles, triangles, or lines using the OBJECTS-AREA symbols. New in 809, Whole counties will change color based on WX Warnings transmitted by specially formatted APRS Messages. See COUNTY WARNINGS below. WEATHER ONLY - The JUST-WX command for a temporary display of only WX stations on the map or P-List. Use the WX-JUST-WX-ALWAYS command to lock this feature on and off. The N-NEXT command cycles through each WX station in turn with a circle on the map and displays its wx conditions at the top of the screen. TROPICAL STORM WINDS - a special format causes APRS to color huricanes red, tropical storms yellow and depressions blue. It will also show the radius of the winds with colored circles offset in the direction of the danger quadrant proportional to the storm speed of advance. DDHHMM/LAT/LONG@CSE/SPD/TS/www^GGG/ppp>RRR&rrr Where @ is the symbol for a Huricane / is the symbol for a predicted posit CSE is direction of movement SPD is speed of movement TS, HC and TD are types of storm www is sustained wind speed GGG is peak wind gusts ppp is central pressure RRR is radius of Hurrican winds rrr is radius of TS winds DEAD RECKONING - APRS dead-reckons moving objects, so the symbol on the map is presented where it SHOULD be, NOT where it was when first reported. After two hours with no update, the symbol fades to dark gray. NWS STATION PLOTTING - Hit MAPS-OVERLAYS-NWS to see all NWS Sites METAR BULLETINS - Suggested by KD4UYR in FLorida, this feature parses NWS METAR bulletins and plots the WX data on the map. (removed from APRSdos in 837) WX-DISPLAY - You may display WX conditions instead of callsigns on maps: WX-DISP-TIME shows the TIME WX-DISP-TEMP shows Temperature WX-DISP-BARO SHows Baro and rain WX-DISP-WIND Shows winds OPERATOR MESSAGES - APRS messages are ideal for Skywarn traffic. With FILE-PRINT enabled, these messages and WX reports can be scrolled to the printer. STATUS - In addition to weather data included in position reports, the station STATUS packet is also available for additional info. BULLETINS - Bulletins are an alerting mechanism for all stations. VOICE REPORTS - Even non-packet voice stations making a weather report can be placed on the map (like an object) by another APRS packet operator. His station will appear in purple showing that his report has been placed there by another station. COUNTY WARNINGS - APRS can color in counties based on NWS Warnings. Hit the usual label zoom keys ] and [ to see the county name if needed. The formats for these warnings are a message sent to the APRS address of NWS-XXXXX as shown below. These messages accumulate on the APRSdos TRAFFIC page where they drive the coloring algorithm. NWS-WARN :exptime,type,c1,c2,c3,c4,c5, (where c1-c5 are counties) NWS-WATCH:exptime,type,c1,c2,c3,c4,c5, NWS-ADVIS:exptime,type,c1,c2,c3,c4,c5, NWS-TEST :exptime,type,c1,c2,c3,c4,c5, (trailing comma is needed) NWS-CANCL:type,c1,c2,c3,c4,c5, Where: exptime - is the Expiration time in the usual DDHHMM format type - is free text of the type of warning c1 - c5 - 1 to 5 counties truncated to 9 bytes or less each NOTE: If the type of warning is longer than 10 bytes, then only include 4 counties per line to prevent truncation by APRS on receipt. In APRSdos, maps with county map labels of the form SS_COUNTY which match the counties in the C1 to C5 fields above will change color. These fields are limited to 9 characters according to these rules: 1. SS_ is the state abbreviation 2. Next 6 chars must be first six chars of County name, omit spaces and abbreviate SAINT to ST, PRINCE to PR, etc... See COUNTIES.TXT for details in making the labels for your maps. Since there is not room for all 3000 Counties in my larger regional and USA maps, in these maps, the entire state will color based on the SS_ formats. Or you can trigger a whole state with SS_STATE. NATIONAL WEATHER SERVICE HOURLY METAR BULLETINS *** This capability was removed in 8.3.4 to make more room *** It was retianed in the APRSwx.exe version. Based on work by KD4UYR in Clearwater FL, the MAPS-OVERLAY-NWS command searches the NWSposns.POS file and temporarily displays all NWS stations within the boundaries of the current APRS map display (up to 250 miles). You are given the option of a one-time map overlay or to add the sites to your P-LIST. The WX-GET-METAR command is used for loading a file of NWS METAR reports. This file can be obtained from most of the commercial data servers or some BBS's, or on the internet at: http://weather.noaa.gov/weather/metar/shtml APRS will scan the NWS METAR file for each station on your P-LIST. For each match, it will parse the Winds, temp, dew point and pressure onto the P-list and places the rest of the report on the L-list. The packet times in the P and L-list will be the time of the NWS report (in local time). The date is assumed to be the current date. Once the data is loaded, you can uplink selected stations to the APRS net as desired. Once everyone on the net sees the reports, the uplinking station should consider Quitting the uplink in order to reduce QRM. DEMONSTRATION: To see how APRS works in a SKYWARN or other reporting net, load the backup file SKYWARN.BK using the FILES-LOAD command. To demonstrate the NWS capability, center your map on Illinois at the 128 mile range, enter the MAP-OVERLAY-NWS command and select the Add option to add them to your P-List. Next, enter the WX-GETmetar command to load the sample METAR data file. Look at the P and L-lists to see what is going on... METRIC MEASUREMENTS: Select wind speed in KPH and temperature in Celsius by toggling the WX-METRIC command. Make this permanent, by saving a CONFIG file. The on-air APRS WX protocols, however, still will be in MPH and F. Also, the ALARMS are compared to MPH and F values. WX ALARMS: If a WX report comes in that exceeds your WIND, TEMP or RAIN alarm values, the station is plotted in RED and an ALARM sounds. This can be used to warn of the passing of a warm or a cold front. CLEARING ALARMS: When an alarm occurs, the station is drawn in RED and the map is re-drawn to center on that station. Also, the station is marked on the P-list with the ALARM marker. TO clear the alarm, simply hook the station on the map, and then UNhook it (hit ENTER twice), or use the WX-ALARMS-CLEAR command. To clear the A on the P-list, hook the station and hit the A key. Normally, the ALARM on the P-list will only sound if that station MOVES. Since a WX station should not move, there is really no problem in leaving the A on the Plist until convenient to remove it. WEATHER WARNINGS AND WATCH BOXES: You can use the OBJ-AREA-LINE command to draw a box from 400 feet to 400 miles plus-or-minus X miles from a line between points A and B. The line and width are perfect for WATCH and WARNING boxes. Use the normal INPUT-ADD-AREA-LINE command prompts which will indicate the +/- sidelines in a 3 digit number of Miles enclosed in braces {075} anywhere in the COMMENTS field. HOME WEATHER STATION INTERFACE: With 2 serial ports, APRS can insert the ULTIMETER or DAVIS conditions in your position report. ULTIMETERS that output data with a * output wind in MPH and those with a # in KPH. APRS averages the wind value over the last 4 samples, so the default rate is every 15 seconds to yield a running 1 minute average. RAIN VALUES: Rain is counted in increments of 0.1 or 0.01 inch or 1mm. but reports all values in 0.01 inches over the air. Since raw rain counts have no meaning without knowing when they were last reset, APRS only compares the difference in rain for the last hour (rXXX) and the precipitation in the last 24 hours (pXXX). A reading of r123 means 1.23 inches fell in the last hour. After 60 minutes, this value will return to zero. A reading of p164 means 1.64 inches have fallen since the same hour yesterday. For REMOTE ULTIMETERS with only a TNC and no PC, the P value means rain since MIDNIGHT and an uppercase Pxxx is used. Also since there is no RAIN per hour value, that field is replaced with the raw rain counter #xxxx. FORMATS: APRS re-formats data from attached WX units and transmits the data as shown below. For remote Ultimters, where there is no PC, the TNC just transmits the raw data, but APRSdos converts them to these formats for display on the P-LIST. (In the future we want to minimize these raw packets since they cannot be decoded by all stations). _CSE/SPDgXXXtXXXrXXXpXXXdU-II Original U-II auto _CSE/SPDgXXXtXXX#XXXdU2r Original U-II remote _CSE/SPDgXXXtXXXrXXXpXXXbXXXXhXXdDvs Davis WX station _CSE/SPDgXXXtXXXrXXXpXXXbXXXXhXXdU2k U-500/2000 with APRS _CSE/SPDgXXXtXXXPXXXbXXXXhXXdU2kr Remote Ultimeter Logger _CSE/SPDgXXXtXXX#XXXbXXXXhXXdUpkm Remote Ultimeter Pkt Mode _CSE/SPDgXXXtXXXrXXXpXXXPXXXhXXbXXXXX%type NEW FORMAT APRS793 June 97 NOT BACKWARD COMPATIBLE Where: CSE/SPD is wind direction and sustained 1 minute speed t is in degrees F r is Rain per last 60 minutes p is precipitation per last 24 hours (sliding 24 hour window) P is precip per last 24 hours since midnight s is snow b is Baro in tenths of a mb h is humidity in percent. 00=100 g is Gust (peak winds in last 5 minutes) # is the raw rain counter for remote WX stations. See notes on remotes % shows software type d=Dos, m=Mac, w=Win, etc type shows type of WX instrument With the WX interface enabled, the normal APRS decaying of position/wx reports still holds as long as nothing changes (except the wind). If any other WX value changes, then the period is reset to the alt-SETUP-POSrate value. The WX-WIND command can be used to set a Wind threshold which will force a WX report whenever the wind is above that threshold. WX PERIOD: APRS decays to 10,20,or 30 minute rates depending on the number of digipeaters. For a weather station, you should change the MaxPeriod to maybe 10 minutes or so using a text editor in your CFIGxxx.APR file. There it is expressed in seconds. Of course, a WX/position report will be transmitted by the APRS station at anytime, in response to an APRS or WX query. ULTIMETER INTERFACE CABLE: Peet Bros sells an interface cable with a DB-25 connector to RJ-11. Since the U-II has no negative supply, a 5 K pulldown resistor is added to the DB-25 connector between Pins 2 and 3. This uses the -5 or -12 volts on the unused TXD line to bias the RXD line. You can use a common phone line plug for their serial output. I found the data on the green while using the black wire as ground. If your connector was crimped on backwards, red is data and yellow is ground. The Peet Bros cable includes transient protection and RF filtering to protect your computer as well as providing the bias resistor. Remember, the annemometer is like an antenna, high in the air. It can radiate RFI and take lightening charges... The U-2000 is directly RS-232 and needs no pull down resistor. Be sure the U-500/2000 is in DATA-LOGGER mode. DAVIS INTERFACE: You must have the DAVIS Weather Link serial interface option before your Davis station will output serial data. Simply connect their connector to your PC. You MUST use the APRS alt-SETUP-OTHER-AGL command to set your average ground level. This converts your baramoter readings to their equivalent value at sea level... Your objective is to find an exact AGL that will result in your BARO readings matching the readings on your instrument or local NWS. THis AGL will probably NOT be your true AGL. SAVE A COMM PORT! You can use a simple 89 cent switch to allow other devices to share a single COMM port with your WX station. Since the WX stations only use ONE pin and GROUND, simply add them to your MODEM cable with a simple SPDT switch as follows: ULTIMETER-II >---------*--------* sw1 | <----*--------------> RXD MODEM } >------------------* or } | other } *-----/\/\/\/\-------* serial } 5.6k | device } <------------------------------*-------< TXD } * * * -----------------------------* * * other pins } *--------------------------------------* GND Actually, you can wire this to any serial device that you do NOT use while running APRS. I chose my MODEM that is on COM2. Note the series resistor as mentioned in the text to provide the -V pull-down for the U-II output. REMOTE ULTIMETER OPERATION: Only the Ultimeters from Peet Bros can be used as remote WX stations using only a TNC and a radio. This is because they output continuous data without needing a PC to interrogate it periodicaly. There are two ways to time the transmission of this data for the packet channel depeneding on what Ultimeter you are using. We call these PACKET mode or DATA LOGGER mode (though neither of these modes is now recommended). DATA LOGGER MODE (GPS mode): U-II - These units output 14 bytes continuously beginnning with * or # U-2000 (old) - These units output 44,48,or 52 bytes beginning with !! For the DATA LOGGER mode, the TNC must do the scheduling of packets just like the TNC does for continuous GPS data. Just program your TNC to think that the WX data is GPS data by entering the #, * or !! instead of the usual $GPRMC data typically used for GPS. Then set the timing for each transmission to be about once every 5 minutes. Be sure to SET ECHO off if your ULTIMETER-II uses a resistor on the TXD line to bias the RXD line! (Otherwise you will echo all heard packets back onto the channel! KD4GOE figured that one out!). PACKET MODE : U-500 - Outputs 44,48,or 52 bytes beginning with $ULTW This mode was designed for APRS packet since the WX unit only outputs a single data line every 5 minutes. Since it is already timed to once every 5 minutes, all the TNC has to do is be in UI CONVERSE mode and it will send the packet. Be sure to use a TNC that can be configured to power-up in UI-CONVERSE. Try UIMODE or PMode-CONV depending on your TNC. ALso you must set LFIgnore to ON so that the LF after the CR is not transmitted.. Since the Kantronics TNC's do not have LFIGNORE, you must set SENDPAC to $0A (linefeed) and set CR off! If there are dozens of REMOTE U-500's, hopefully their clocks are staggered enough that they wont all transmit at EXACTLY the same time. CAUTION: Only U-500's and only U-2000's manufactured after April 97 should be used in packet mode. U-2000's prior to that date will not show wind in the packet mode. And these days, raw WX packets on the main APRS channel are not reeommended. WX POSITION: In both cases, you must put the unit's POSIT in the BText using the "_" WX symbol. This way the TNC transmits two packets, one is a BText WX posit with no WX data, and the other is raw WX data with no posit! APRS cannot display the WX on the map until it has received a WX posit beacon. So, set the beacon to go about once every 20 minutes. Once the posit is received it will be displayed as a Blue dot unless the site is also acting as a WIDE-RELAY digipeater, and it will show GREEN if the delimiter between the LAT/LONG is set to a backslash instead of the usual forward slash. WX LOGGING: Use the WX-LOG command to turn WX-LOGging on and off. It will show on the control panel when on. If ON, then on-air reports are saved when received every 10 minutes or so, and your own report will be saved at the rate set by the Set-Pos-Rate command.