HELP.TXT 6.0 APRS HELP DOCUMENT In most cases, all APRS commands are active from all pages and APRS processing of packets continues in the background. (An exception is while a BLUE-BOXED prompt is on the screen). The first Help page defines all command characters. All APRS commands are single key strokes. Some keys bring up additional command sub-menu's on the bottom of the screen. Just hit the first letter of any command listed in the prompt. In most prompts, the ENTER key will select the default choice or complete the prompt with no action. To begin with, APRS has nine major display screens: MAP - For showing the positions of all stations and objects LATEST - Shows the latest Beacon or broadcast message for all stations BULLETINS - Shows all general announcements posted by other stations POSITIONS - Shows position packets and comments from all stations and Objs HEARD LOG - Shows station activity in number of packets per hour per station READ MAIL - Shows the last 23 message lines heard between any stations DIGIs USED- Shows digipeater paths used by all stations (or DX message list) ALL BCNS - Chronological log of all beacons and messages (or all DX spots) VIEW - Scrolling screen of all packets on frequency DISPLAY SCREENS: Each display page is called up with a single key command as shown below. If there are more than one page of packet stations in the net, then use the PgUp and PgDn keys to cycle through multiple pages. On both the P and L lists, you can move the cursor to select a single station. A prompt then allows you to (1) display the object on the screen, (2) see a chronologi- cal list of all previous beacons from that station, (3) delete the entry, (4) insert a position for a BEACON only station, etc. L - LATEST DISPLAY - Lists the latest BEACON packet from all stations. This screen is like a braodcast message display showing the latest bulletin from each station. In DX mode, this screen lists all stations on your local cluster and their latest outgoing packet. B - BULLETINS DISPLAY _ Shows the latest 22 APRS BULLETINS. This screen is very useful for distributing useful net-wide information about special events or instructions. Any station can post multiple lines to all stations using these BULLETINS. See the SEND command P - POSITIONS DISPLAY - Lists the latest POSITION packet received from each station. Since each position report can contain comments, this display is useful for seeing comments and resolving position data. You may select (HOOK) any station or object in this list for manipulation. See the section on OBJects. Also the JUST ONE command works on this display to show JUST one type of stations at a time. On the PList, you can HOOK any object or station with the cursor and then you may execute a number of different commands on that object: U or Q - Uplink or Quit uplinking that object Move - Move it anywhere else on the map Show - Center the map on the object Delete - Deletes the object from your list Just - Lists only stations or objects of JUST one type Kill - Stops display of your object on EVERYONE's screens! It remains in their list but just does not clutter the map. H - HEARD - This display shows statistics of the number of packets heard from each station for the last 24 hours. It is useful for observing station activity and on HF for observing propagation changes. R - READ MAIL - This screen monitors all messages on the frequency and keeps the last 23 lines heard. This screen is useful for "READING the MAIL" In DX mode, also collects TALK messages between DX cluster users. D - DIGIPEATER PATH - This display shows the raw packet header including the digipeater paths used by all stations in your LATEST list. Proper use of digipeaters is very important for minimizing QRM on APRS nets. In DX mode, this screen accumulates the list of all ACTIVE MESSAGES. A - ALL PACKETS - This display shows a chronological history of all packets received. It also includes your incoming and outgoing message lines. Since messages do not have a time of receipt appended to them, this display is useful for seeing approximately when a message line was received. In DX mode, this screen accumulates all DX/WX/WWV spots and all announcements. F1- HELP - Gives a menu of several different pages of HELP. New in version 6.0, you can now read all of the README files on-line using the F1(HELP)- FILES command. Other screens in the help menu are as follows: AEA - Hints on how to initialize the non standard AEA products DIGI - one screen on how to use APRS DIGIPEATERS FILES - New in 6.0, lets you read README files on line HELP - Full page listing of all APRS Commands INFO - A screen of additional helpful information MORE - A second page of help NEW - New-user simplified help screen On-SCRN - Scroll through the commands without losing the current screen SYMBOLS - Shows all the APRS symbols available VALID - How to validate your copy of APRS MAP DISPLAY: The map display is the most important display in APRS. It shows a map of the packet network area and the positions of all reporting stations. Stations reporting packet positions over the air are shown in white, objects that you are reporting to the network (uplinking) are shown in yellow, objects reported by other stations are shown in purple, positions that have not been updated in 2 hours are shown in dark gray. Stations shown in light gray are beaconing a position, but do not have APRS on line. To help highlight the WIDE area digipeaters in an APRS net, the WIDE digipeaters are shown in green. All weather stations are shown in blue. and finally, all moving objects that have been deadreckoned, are shown in light blue. SPACE - Displays the current map. By marking important or special objects with a # on the P-list, you can display the map with all other stations or objects suppressed by simply hitting the # key. If you press *, all symbols will be displayed, but only the calls of the marked stations will be shown (useful for tracking a mobile through a maze of fixed stations..) ARROWS - Move the map cursor on the screen. If you turn NumLok off then hold the shift key with the white arrow keys, then cursor will move 5 times faster. PgUp/Dn - Zooms the display in and out by a factor of 2. Ctrl-PgUp/Dn zooms by a factor of 8. Home - Will home the center of the screen to the current cursor location ESC - Will escape the cursor from never-never land to the screen center End - Will return the map to your default position stored in CONFIG file 1,3,5,9 - These are map memories that you can use to save particular maps of interest to you. Save a map using the MAP-SAVE command and recall any of these using the indicated number key. The 1 key always has the whole USA in it. F9 - CENTER ALL CONTACTS. This special function will calculate the best map range and center ALL stations heard by you on one map. J - JUST ONE - Used to display just one symbol type at a time. to selectively display stations like all WX stations. # - Will display the map with ONLY the objects or stations marked on the P-list with a #. Very useful for highlighting special event objects with a single key stroke. * - Similar to # above, but displays all objects, but only the calls of the marked stations. HOOK - Hook is a Navy term for selecting an object on a radar screen. Use the RETURN/ENTER key to hook an object at the cursor location. To progressively hook one object after another, use the +/- keys. The POSITION and BEACON packets from a hooked station are displayed on the bottom of the screen. While a station is hooked, it can be moved by moving the cursor to the new location and hitting the INSert key or it can be removed using the DELETE key. To prevent inadvertent movement of objects, a second RETURN key UNHOOKS. INSERT - Relocates a HOOKED object on the screen. DEAD RECKONING: Since APRS dead-reckons the position of moving objects as time progresses, the light blue symbols on the map are presented where they are predicted to be, NOT where they were at their last report (unless DR is off). If you use the cursor to try to hook one of these objects on the map, you must hook the little gray circle which marks the position of the actual report, and not the symbol itself. MAP MENU: Many of the MAP features and other commands affecting maps have been moved to the MAP MENU. The following commands apply: A - ALTmap: Displays the map UNDER the current map. Since APRS always uses the latest map in the MAPLIST.APR file that meets the current screen conditions, areas where maps overlap may sometime be obscured. This command displays the next higher map in the list. B - Borders: Shows borders of all MAPS in the MAPLIST.apr file. If A map border appears, but does not come up, then the MAP file is missing. If the Map file exists but the borders do not show up, then the file is not listed in the MAPLIST.apr file. Use F3 and F4 to display more or fewer borders. See Hierarchy command below. F - Features Toggles a number of map features on/off. Features are Boundaries, Headings, Roads, Calls, Waterways, etc. ALL features can also be turned on/off at once. This is useful for slow 8088 PCs where turning off the map still shows the relative positions of stations but without taking the 10 seconds required to draw the maps. G - Grids: Select any of the following: CAP - Overlays the Civil Air Patrol search and rescue grid system. GridSquare - Displays Maidenhead grid squares H - Hierarchy: This is an improvement on the BORDERS command since it colors in the maps in the same sequence as they are listed in the MAPLIST.xxx file. The overlapping colors show the effect of the sequence of this list. L - Locks the current map. This defeats the normal APRS auto-map select feature so that you will not be interrupted if your cursor gets over on another map during a special event. R - Rings. Select from a number of Range rings: DFrings: Displays Signal strength contours around all stations reporting signal strength on a fox/jammer. Stronger signals are brighter red and null reports are black circles. POWER rings: Displays range rings around all stations on the map showing an estimate of the horizon from each station based on their transmitter power, height above average terrain, antenna gain and favored direction. If specific parameters are not given for a station, then the defaults used are 10 watts, 20 feet, and 3dB gain, omni. RANGE RINGS - Displays one ring at the current range scale and another at half the range. This display also shows the range and bearing of the cursor from the center of the map. This is limited to 256 miles since it does not calculate great circle spherical results. MESSAGE TRAFFIC: There are three types of messages in APRS. The first is simply your one-line BEACON that is always transmitted to all stations. New BEACONS are shown at the bottom of all USER's screens on the net and are highlighted in green so that all stations see the new message or change in status immediately. These BEACONS are also added to the ALL and LATEST pages of all stations on frequency. These beacons are perfect for alerting the net to your current status. Secondly, APRS implements a one line TALK traffic capability between operators. Each line is ACKed when received by the other station. Multiple lines can be buffered up for eventual delivery. Finally, after APRS version 506, any station can sent a multi-line BULLETIN to all stations. See BULLETINS page and the SEND command. TRAFFIC COMMANDS: B - Displays any Bulletins. T - Displays traffic on the current screen. If messages are already on the current screen, then T forces a one-time transmission of all messages, without changing the current timing. Whenever you call up a new APRS screen, the messages are overwritten. They will reappear if there is any change, such as an incoming message line or an ACK to one of your outgoing lines. S - SEND MESSAGE - You are then prompted for the callsign of the station that you want the message to go to. If you already have outgoing message lines pending, then the previous station callsign is pre-loaded. If you don't want to send the message, just enter a blank line. If you have hooked a station on the map, then that stations CALL will be pre-loaded. NOTE: The channel effeciency of APRS TALK messages are no better than normal connected packets since they also require ACK's. Intense real-time rag-chews on a busy APRS frequency should be done without digipeaters or with only the exact path specified; See the OPS-DIGI command below, for a shortcut for rapidly changing your digi path. The more effecient way to keyboard is to just use the OPS-COMM command and use your TNC to connect to the other station using the most direct path. The other operator MUST be at his keyboard, though, because APRS will time-out, erase his screen, and dump him back into APRS after 3 minuntes of inactivity. ACKS: When your MSG is acknowledged, the word *ACK* (or *REJ* if his screen is full) will be over printed on the outgoing MSG line. Note that unlike normal packet, APRS does not compute the return path for an ACK. Each station must set his outgoing VIA path so that his packets (including ACKs) get back to all stations in the net. On the 3rd DUPE of an incoming message, APRS will warn you that the other station is probably not getting your ACKS! In version 505, APRS waits 30 seconds and repeats the latest ACK once to provide an almost doubling of through-put on poor (HF and multi-hop digipeater) paths. S - SEND BULLETIN. This is the same as the SEND command, but you simply send the message to BLN# instead of a callsign. The # indicates which line of the bulletin it is (1 to 9). All stations that see a message addressed to BLN# will grab it and sort it onto their BULLETINS page. Notice, since no one ACKS these message lines, they are transmitted forever at the normal APRS decaying perodicity, eventually being sent about once every 15 minutes. This way, new stations checking into the net will eventually collect all old beacons still being transmitted. You can update or change lines, just be sending a new one with the same BLN number. K - KILL incoming message lines. K key kills one line at a time. E - ERASE outgoing lines. E key erases one outgoing line at a time. First it erases *ACKed* messages, and then erases other lines. FILES MENU: All commands dealing with files have been placed in the FILES Menu. These commands are as follows: A - APPEND - This will permit you to load in a BACKUP file without losing all the stations that are already in your P and L lists. If the same calls are in the appended file as are already in memory, there will be numerous dupes that should be manually deleted. Also, APPEND does not append any LOG or WHEN-HEARD data. C - CHANGE-MAPLIST - This command finally lets you build and use multiple MAPLIST.xxx files customized to your area and application. D - DOS Shell - allows you to shell to DOS. Be sure to return to the APRS directory before you EXIT back into APRS. L - LOAD - This key allows you to load a backup file. The file named BACKUP is saved every time you quit APRS so that you can restart the program to the last on air situation. I save a different file for each packet frequency so that my map only shows stations on the current frequency. To facilitate this process, you only need to enter the numeric digits to LOAD a backup FREQxxxx or HFxxxx file. To load the BACKUP file, just enter the letter B for the filename. O - ORDER THE LATEST LIST - Moves older beacons to the start of the list, and the most recent beacons to the end. S - SAVE - Used to save the current situation in a file. The file name defaults to the name of the last file loaded. It is a good idea to save a separate file for each packet frequency on which you operate. If any filename other than the BACKUP default is entered, then APRS will also automatically save a LOG and Track HIStory file. If you select NONE as a file name, then nothing will be saved. OPERATIONS MENU: C - COMMS - This commmand allows you to disable APRS and talk straight through to your TNC or GPS/WX/DF COMM port. Use it to establish a direct CONNECTION. This is useful for connecting to another APRS station's internal TNC mailbox to leave a message if he is not on line with APRS or for a quick keyboard to keyboard QSO with another APRS operator, known to be at his keyboard. These brief keyboard connections are not too disruptive to other APRS operations on frequency as long as no computer data is transferred. Also permits you to monitor your other COM port hooked up to GPS or WX. D - DIGIPEATER PATHS: This is a very useful command that allows you to save and later use a variety of digipeater paths. You can save up to 13 different paths. Simply hit S to save your current path into one of the memory slots. The L key will display a list of already saved paths. When you are in QSO with one station in particular, choose the minimum path to that station to minimize QRM on the channel. F - FIND: This command allows you to find a callsign or a gridsquare. If you enter the first character as a [, then APRS will asume the entry is for a grid square. If you just type a callsign, then APRS will search for the given callsign. If you are on the MAP, then the station will be identified. If you are on any other screen, APRS will jump to the page that holds that callsign. Q - QUERY: This command sends out an APRS query packet (in about 5 secs) to all stations on frequency. All APRS stations will respond with all of their BEACONS, POSITS, OBJECTS, and MESSAGES sometime in the next 2 minutes. This command is AUTOMATICALLY sent when a station starts up the APRS program. This is why you hear a lot of packet activity each time a new APRS station fires up on frequency. You can selectively Query any single APRS station by sending him a one- line message with the characters ?APRS in it. P - PING - Sends out a ping packet. If the packet is digipeated by your selected VIA path, you will see it monitored on the bottom line of your display. This lets you know that your station is transmitting and that the digipeater in your selected VIA path responded. U - UNPROTO Used to set up your outgoing digipeater path. (IMPORTANT!) If you have not selected a digipeater that covers your APRS net, then your packets and acks will never get to the other stations on freq even though you see them fine. YOU MUST SET YOUR VIA PATH TO COVER your intended APRS AREA by selecting an appropriate digipeater path! APRS will warn you if another station does not appear to be getting your message ACKs. INPUTS MENU: Lets you ADD objects to the map, or input data on your station. Any station may ADD an object on the map for display at all stations. Once on the screen, the object is listed in the P-list with a (+) symbol. This means it will be transmitted by your station. You can QUIT transmitting each object by hooking it on the P-list and hitting Q. Users with an un-validated copy of APRS are limited to uplinking only one object. Even if you delete the object from your screen, or have quit sending it, it still remains on all screens in the network until each individual operator deletes it. To remove it from all screens, you can kill an OBJECT instead of deleting it. Your station will continue to transmit the object, but with a special KILL mark on it. It will disappear from all maps, but it will REMAIN in everyone's PList. If an object has not been updated in over two hours, it fades to a dark gray color. In some of these commands, you are prompted for the LAT/LONG of the object. APRS pre-loads this prompt with the LAT/LONG of the cursor. If that position is correct, just hit ENTER, and these values will be used. TO change these values, just type in a new value. You may type as few characters as needed to give the resolution you need. But you MUST always type the required LEADING ZEROS in longitudes below 100 degrees. A - ADD a new object to the screen at the current cursor location. You are prompted for all pertinent information. There are over 50 symbols that can be used to display the object. Some are specific and some are generic so that they can be defined for each special APRS net. D - DIRECTION FINDING: This command allows you to enter a beam heading or a signal strength report for your own station during direction finding events. A zero (0) bearing indicates a signal strength report. M - MyPOSIT: This command added in 5.7 permits one step updating of your position without having to first hook yourself. This makes updating your position while APRS mobile with a good map, so easy, that you only need GPS if you are lost! P - POWER: This is the command used to enter your transmitter power, height above average terain, antenna gain, and directivity. This makes sure that your station range will be properly estimated. CONTROLS: There is a status display called the control panel which can be displayed at the bottom of the screen. It shows the status of all toggle on/off functions, your validation status and your VIA path. Items in lower case are OFF and upper case are ON. Example: ------------------------------------------------------------------------------ XMT | UP | DR | LOG | PFL | BCNS | cw | VHF | DIGI-1,DIGI-2 | ------------------------------------------------------------------------------ B - BEACONS - Used to return APRS to monitoring BEACONS only. D - DX mode - Sets up APRS to monitor and display information for DX cluster users. See DX.txt. To exit this mode, select either BCNS or OTHER. F - FADE - This toggles on/off the automatic fade-to-gray for old contacts. Old objects and stations on the screen normally turn to gray after 2 hours. This made backup files of past events look boring with all contacts barely visible! FADE is now turned OFF each time you load a backup file, but after 2 hours, FADE will automatically come back on. G - LOG - Toggles on and off the automatic logging of track histories to file. Default is ON so that after 150 position reports, a file is automatically saved and memory is cleard for further accumulation. If off, the 150 reports are retained in memory until you QUIT. O - OTHER Use this command to toggle the APRS beacon processing filter between APRS Only packets or ALL OTHER packets. The state of this switch in shown on the control line. Use OTHER to monitor non APRS frequencies to collect BEACONS and see who is on the air. With OTHER selected, no packets are saved in the ALL list. P - POS-FILTER ON/OFF - If a position is the same (within 20 yards or .01 minute of LAT/LON), then the report is not saved in memory or to a track history file. If this POSITION filter is on, then the comparison is made out to 80 yards to include most of the randomness added to the GPS system by the Deaprtment of Defense. This prevents non-moving GPS packet stations from filling up track history files with redundant positions. When the 80 yard filter is disabled, this ENABLES the automatic saves of all WX and DF reports to the HST files which is useful for later trend analysis. R - dead Reckoning On/off U - UPLINK ENABLE - Toggles on/off. If on, then your objects marked for uplinking, will be uplinked to all stations in the net. X - XMT ON/OFF - disables routine transmitting from your station. This is good for stations monitoring an event, but not actively participating. It keeps their routine beacons off the frequency. The X key will force a one time transmission of your BCN, POS, OBJ, and MSG packets and your station will still ACK incoming messages. W - CW - In normal mode, if CW is on, then ALL NEW BEACONS will be sent to you in CW. In DX mode, CW is always on, although it can be silenced by using the SETUP menu to turn BEEPS off. If FREQS is turned on, then the operating frequency as well as the callsign will be sounded out in DX mode. Other CW functions: E - Enable D - Disable F - FREQs on S - Set speed T - Test Lines to you are sounded out in CW if you are not near your CRT. Also permits changing speed and selecting Full calls in DX mode. SETUP MENU: This command allows the selection of all SETUP functions. These functions can be saved in a configuration file by registered users B - BEEPS Toggles nuisance BEEPS (and CW in DX mode) on and off. G - GPS FUNCTIONS: Select, or initialize a number of GPS functions: SPM - Single Port Mode (See GPS.txt) HSP - Hardware single port mode (see GPS.txt) KLYNAS - Sets up APRS to work with STREETS-ON-DISK (Klynas Engineering) NoGPS - Used to turn off SPM or HSP without having to restart APRS. TIME-SYNC - Sync's PC clock to the next GPS report received. This command only sync's to the MINUTE. Hours are not matched. Be careful, since stand-alone PACCOMM TNC trackers first store the GPS data and then later transmit it based on an internal timer, the actual GPS data transmitted may not be real-time. This is true if the GPS loses lock or becomes inoperative, (car parked under a tree) then the TNC continues to send the same "old" fix. If you sync to one of these, you are syncing to "old" time! P - POSrate - This command is used to set the periodicity for WX, DF and GPS reports. Normally, APRS resets the decay period to an initial 8 second period each time you manually change your POSITION report, and then doubles the period after each transmission. This algorithm would generate far too many packets from the automatic WX, DF and GPS interfaces. For these interfaces, APRS resets to the period set in the POSrate command whenever the data changes. Actually, this command sets two values. The Refresh rate sets how often the interface is sampled just to update the data on your screen, and the POSrate value determines how often it is transmitted. S - SAVE CONFIG FILE - Used to save your current configuration. Saves the current map size and location as well as the state of HF/VHF, and your digipeater path. You will be prompted for your Validation number the first time you do a CONFIG file save. If you have chosen any of the GPS, DF or WX options, you will also be prompted for your auxilliary registration number as well. You can save each CFIG file with an optional 3 character file extension so that you can call them up quickly for different applications. You invoke the optional files with a /EXT switch when you give DOS the APRSxxx command. IE: C:> APRS406/MOB would load the CFIG406.MOB file which you saved when you operated MOBile. etc T - TNCsetup - sends out TNC commands to setup the TNC for APRS. Your TNC is automatically initialized when you start, but can be done at any time, if your TNC loses power, or needs to be reset to APRS defaults. When you QUIT APRS, it gives a list of TNC parameters that were changed by APRS, and restores any custom commands that you might list in the RESTORE.TNC file. W - WIDE Permits an APRS station to override the normal APRS default ALIAS of RELAY and set it to the generic WIDE area address so he can serve as a temporary WIDE digi. Do this only with the concurrence of others on Frequency. WEATHER COMMANDS: APRS displays weather stations as large blue circles with a white line showing the wind speed and direction. Remember that APRS uses 360 degrees for North and assumes that 000 means no direction information is available. Under the CONTROLs menu, the FILTER command allows you to disable the POSITION FILTER so that WX reports will be saved to track history files for trend analysis. Other WX commands under the WEATHER MENU: E - Enter a weather report. Used to enter a manual WX report. The word (manual) will be added at the end of the report to indicate that it was a one time synopsis and that APRS should not update the Date-Time each time it is transmitted. G - GET NWS SITES - Loads all National Weather Service sites on the present map display into the P-list. This is so that an hourly WX data file can be loaded for all all NWS sites listed. J - Use the J command to select Just Weather stations for display. L - LOAD WX DATA - This key will search a designated file for NWS hourly weather advisories. For each NWS station listed in both the data file and already in your P-list, the current conditions will be loaded. Use the G command to pre-load your P-list with the NWS stations near you. N - NEXT WX STATION - Highlights the next weather station in turn and displays the WX conditions in the weather box at the top of the screen, and circles the station on the map for identification. The Weather box at the top of the screen will automatically be updated everytime the selected WX station sends out a WX report. Q - WEATHER QUERY - Same as QUERY, but only weather stations respond. W - WIND - This command is used to set a Wind speed threshold. Whenever the wind exceeds this value, the WX reporting period is reset to the minimum POSrate value, for more frequent reporting. TRACKING and TRACK HISTORIES - All position reports are saved to memory and eventually to file for subsequent replay. Each new position report is checked against the last position from that unit and the current values. If the POSITION filter is ON (default) then a new position will not be saved to track history unless movement is more than about 80 yards. This is to reduce the number of track points for non-moving stations saved in the file. The 80 yard circle allows for most of the randomness of GPS Selective Availability so that parked vehicles do not generate a lot of packets. If the filter is OFF, then only a single digit change in a position will generate a new packet report. ALso, when the filter is off, ALL WX and DF reports are saved to file. This makes it possible to save a DF event, or to keep historical WX data. There are several commands related to station tracking: T - TRACK - This is a subcommand on the P-list display which allows you to designate a station for tracking. If TRACK is on, then the map will always re-center on the selected station whenever it approaches a map edge. This re-centering anticipates the station's movements and recenter's the map to give the best next view. A - ALARM - This is also a subcommand on the P-list which allows you to set an alarm on a given station. If that station moves, APRS will beep and will re-center the map to track that station. The same filter as used on the P-list is also used here so that the randomness of Selective Availability does not unnecessarily trigger this alarm. You can silence the beeping by UNHOOKING the station, or by deselecting the ALARM function. Only one ALARM can be set at a time. M - MOVE - A subcommand on the P list for moving a station. Similar to just hooking it with the RETURN key, but is the only way to move an object or station with 00000/00000 for LAT/LONG. S - SAVE FILES - On the FILES MENU, this command forces a save of a BACKUP a BLxxxxxx,LOG and a TKxxxxxx.HST file. If you are in the field, and may possibly lose power, do a SAVE now and then, to be sure you save all track histories. After the event, you can use a DOS text editor to append all the track history files together for the one event. When you Quit APRS, ONLY a Backup file is saved, the LOG and TRACK data are LOST! If, however, you give the BACKUP file any OTHER name, then a LOG and TK.HST file ARE saved when you quit. REPLAY - Found in both the FILES and OPERATIONS MENUS. One REPLAYS from on-line memory, and the other from a previously saved TRACK file. Track histories are retained in memory for instant replay up to 150 points. When memory is full, a file is automatically saved and memory cleared for more points. If less than 150 points are in memory, you MUST MANUALLY force a save BEFORE exiting the program or the track history points in memory will be lost! During Replay several commands are useful to center the screen on the moving object, change the speed of replay and zoom in or out, etc. In version 5.8, the map will AUTOTRACK a moving station if only one station is indicated in the user response to the TRACK-which-station prompt. DIRECTION FINDING: APRS can instantly traingulate fixes from many reporting packet stations, and even show overlapping signal strength contours from stations with OMNI antennas. This new OMNI feature is a tremendous advantage, since it permits the 95% of HAMs who do not have beams or DF gear to partici- pate in FOX hunts. The traditional beam-heading reports can either be automatic from the N7LUE or DSI Doppler serial interfaces, or manual from other APRS stations. Even stations reporting a beam haeding that are not APRS equipped, can be placed on the map by any APRS station using the INPUT-ADD command and be given a beam heading. APRS assumes that any station or object using the TRIANGLE symbol is a DF station and will plot a line of bearing if given. Note that APRS uses 360 degrees as North and assumes 000 means no direction information available. A quality of 8 indicates an excellent fix. The main DF command is in the OPERATIONS menu. For more info, see DF.txt. SIGNAL STRENGTH - By entering a 0 as a beam heading (APRS uses 360 degrees for due north), APRS will assume the report is a signal strength report and will prompt you for your antenna height above average terrain and antenna gain. To see the overlapping signal strength contours on the map, use the MAP-RINGS-DF command. APRS will plot colored circles around each DF report who's brightness is directly, and who's radius is inversly proportional to signal strength. Note that you MUST UNDERSTAND what HEIGHT-ABOVE-AVERAGE-TERRAIN means, for this to be useful. If you are getting voice reports, be sure the person is giving a true assessment of his HAAT in the general area. Or at least in the general direction where the FOX is suspected. BEARING - If you enter any other bearing, APRS will prompt you for the quality of the fix, and then will plot the bearing from your station. heading for your station. If you are running the WX station option, it will be dissabled while the DF report is operative. You may also specify a Quality factor 1-8. The more dotted the line is, the less its quality. FADE-CIRCLE TECHNIQUE - This is a new technique in version 5.9 that has been used by pilots for locating emergency beacons. It assumes that for any given mobile receiver, there is a unique circle around the transmitter where the signal fades out. All the mobile station has to do is plot three points anywhere where the transmitter signal just fades in or fades out. These three points define a circle with the transmitter at the center! APRS implements this technique with single keystroke operations. Each time you press F5, a Fade point is entered on the map.