Portable APRS Tracker + Messenger
AprSVW
(IK3SVW)
Are you mobile? Would you like to take a look at the APRS traffic and at the same time send your position detected by a GPS at fixed or variable time intervals with your speed? Do you also need to automatically receive and send confirmation to an APRS message destined only to you, and maybe already that you reply to the sender with a short personal message?
Do you want to do all this without a PC or an expensive rtx with special aprs features?
So it’s for you AprSVW, a small, low-power portable APRS decoder / encoder that uses a 4×20-character LCD display. To summarize, with AprSVW connected to a specific FM transceiver operating on the APRS frequencies it is possible to:
- generic monitoring of the 1200 baud Packet traffic;
- decode and display data from the APRS stations at 1200 baud;
- receive and automatically send acknowledgment of receipt (ack) to an APRS message addressed to you;
- view at any time the last APRS message addressed to you, signaled acoustically at the moment you arrive;
- compose and transmit a short message to an APRS station of your choice, checking if the sender has confirmed receipt (ack);
- display and transmit your position in APRS (detected by a GPS), at predetermined time intervals;
- send a fixed position, in case you do not own a GPS or be for example at home.
File containing all the necessary material (diagram, firmware, instructions) to create AprSVW v3.0, which has the predisposition to connect in place of the two buttons a small interface for rotary encoders of universal type, useful for speeding up the writing operations of the message . All information for the implementation of the encoder interface is also included in this file.Although AprSVW can edit and save your name, the recipient’s name and the APRS message to be sent and you can activate / deactivate the autorisposta, you can configure entirely AprSVW v3.0 from a PC using the following software called AprSVW Config:AprSVW_Config_v30.zip (v3.0 1,79MB 03/2007 italian / english)
Installation package for Win95 / 98 / Me / 2000 / XP of AprSVW Config, software that allows you to configure all the parameters of AprSVW v3.0 via PC via RS232 serial interface.
Note: I recommend uninstalling any software versions prior to v3.0.
The scheme of AprSVW v3.0 is very similar to the Peek_SVW which is an APRS viewer, in fact the same integrated ones are used: PIC16F628 and FX614 (MX614). It is also possible to use a PIC16F628A.
Note:
The integrated MX614 (FX614) is not easy to find,alternatively, the integrated TCM3105 can be used instead of the MX614, so the AprSVW30.zip file also contains the wiring diagram for the TCM3105.
AprSVW must be connected to an FM rtx in this way:The BF output of the RTX must be connected to the “Audio In” of the AprSVW.
The microphone input of the RTX must be connected to the “Mic Out” of the AprSVW.
The PTT contact of the RTX must be connected to the “PTT” of the AprsVW. Many portable RTX models do not have a PTT contact and in this case a 2.2KOhm resistor must be connected to the “PTT” and “Mic Out” of the AprSVW.It is very important that the rtx DOES NOT have the squelch open but rather adjusted for normal use, ie the BF output must be muted in the absence of an RF signal. The RS232 serial connector of AprSVW serves two purposes:As a GPS input: simply connect the GPS serial output directly to the serial connector of the AprSW. The GPS must be set to a serial NMEA output at 4800 baud.
As a data input from the PC: in this case it is necessary to use a NULL MODEM cable to connect the serial output of the PC to the serial input of the AprSW (in practice just exchange the connections to pins 2 and 3 of a normal serial cable ).Other links:Instead of the two Set and Select buttons, it is possible to connect a rotary encoder interface with a push button to speed up operations. Find schema and instructions included in the same AprSVW file (AprSVW30.Zip).
The buzzer, which has the function of signaling an incoming message, can be replaced, for example, by an LED or other signaling device.
The manual, included in the zip files, explains in detail the four available screens, numbered from 1 to 4, summarized here:Extended display of all incoming APRS (UI) packets. When this is switched on, this screen is selected.
Display and setting of name, and display of the last message received (addressed to your name).
Display, setting and transmission of APRS message on exit.
Mixed view of incoming packets and their coordinates, speed and direction detected by the connected GPS.You can change the screen by briefly pressing the Select key (if you are not setting data), this will display the screens 1-2-3-4 in a cyclic manner.
In addition to the PC settings it is obviously possible to make settings directly from AprSVW, how to enter your name, write a message or transmit your position. When making settings, reception is disabled, and a flashing cursor will appear on each character / parameter to be set.
The Select key is used to change screens or to select a character during settings. The Set key is used to make settings (if pressed briefly) or to confirm a set character (if pressed for a long time). When editing the text, the Select button has a repetition if you hold it down for a long time.
If you use the encoder interface instead of the buttons, turning the encoder clockwise simulates pressing the Select key while turning the encoder counterclockwise simulates a short press of the Set key, then pressing the encoder simulates the long press of the same Set key.
Even when displaying screens 2 and 3, if you are not making settings, AprSVW continues to receive APRS traffic even if it is not displayed. When a message addressed to your AprSVW name is received, force the display of screen 2.
Finally, at any time you can force the acquisition of GPS data and the transmission of the position by pressing the Set button on the screens 1 or 4.Example of screens of AprSVW v3.0
Below you can see examples of the four LCD screens, numbered 1 to 4, of AprSVW:
Here you can see and set your name, in this case IK3XYZ-9, and see the last message (addressed to your name) that in the example was transmitted by IK3ABC and contains the text “OK we feel on RU8 between 5 minutes “.
Here we see that the message “SENTIAMOCI SU RU8” is sent to AprsVW (written “TX ..”) at the aprs IK3ABC station, which has already sent the acknowledgment of receipt (written “ACKED”, which in v3.0 replaces the word “TX ..”).
In the upper two rows you see the aprs traffic, in this case the message “Hello” sent from IK2DKX to IW2FUS-9, and in the two lower lines you see your position (Lat 45 ° 40.70 ‘North, Long 12 ° 21.62’ East ), speed (60 km / h) and direction (150 °) detected by the GPS ..
Program AprSVW Config v3.0 to transfer the settings from the PC to AprSVW
At the side you can see how the program AprSVW Config, which allows you to change all the parameters of AprSVW by sending the data through the PC serial port. By permitting F1 it is however possible to call the manual which explains all the parameters and the use of the program.
It starts with TX DELAY, ie the waiting for tx data after pressing the PTT; then choose your icon via ICON Symbol and Alternate Table. In the manual (by pressing F1) you can find the most common icons. Then enter your name in MY CALLSIGN (also editable directly from AprSVW). So you have to set the digs for the aprs via APRS PATH (further info), then set the STATUS text that is the comment to be sent every Status txt every time.
It is possible to check the Disable display position … box so that the coordinates of the received stations are not displayed, to the advantage of the additional information.
It then goes to the transmission times divided into 2 panels, Manual Timing and Automatic Timing, where there are operating times when the GPS is off or on. In this last case you can choose the transmission interval of your position according to the speed detected by the GPS. Continuing we find the parameters Acquisition interval in the GPS box that guarantees a minimum interval of acquisition and display of GPS data, and Acquisition timeout that is important and determines how long AprSVW is dedicated to acquiring data from the GPS: if for example the GPS sends the data every 2 seconds, the Acquisition timeout setting to 25 (2.5 seconds) ensures you always receive data from the GPS. I advise you to do some tests starting from a long time (40 or more) and then go down in order to find the right time for your GPS.
A special case is the GPSless Mode: when you do not have a GPS or in a fixed position, you can send the position by setting the Acquisition timeout parameter to 0 and inserting the coordinates in the STATUS text through a special coordinates input window, as specified in the program.
Note: I recommend never setting the parameters in Manual Timing, Automatic Timing and Acquisition interval to very low values (30 seconds or less). These parameters are rounded to about ten seconds.
Then passing to the specific message box (which can also be entered directly from AprSVW), we find Msg Retries indicating how many times the message is transmitted, and then the “real” parameters of the message to be transmitted: APRS message TO CALL, name to to send the APRS message, and Message text, message text to send.
Finally you can check the Auto send message … box to automatically send the message to the sender of the last message received.
On the last Configuration / Programming pane there are several options: Default sets the default parameters, Save and Load save / read from the disk the parameters, Comm num sets the serial port number, Help recalls the manual and finally the SEND button, which you can press after checking all the parameters and connecting the PC to the AprSVW set for data acquisition (by keeping the select button pressed or the encoder key at power on). The data will thus be effectively sent.
At this point, after checking the success of the sending on AprSVW you have finished, and AprSVW v3.0 will be immediately operational with the new parameters!
Original itallian page: https://digilander.libero.it/ik3svw/aprsvw.htm
Original page (not available): http://www.ir3ip.net/ik3svw/aprsvw.htm
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