APRS for Beginners etc.
Introduction and practical hints, describing the APRS and Weather Station DK5EC
APRS, what does it stand for? A station operating with the Automatic POstion Reporting Sststem amateur basically amateur amateur amateur amateur amateur amateur transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting its transmitting its transmitting its transmitting its transmitting its transmitting its transmitting its transmitting its transmitting its transmitting its transmitting its transmitting its transmitting its transmitting its transmitting its transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting transmitting packet. Besides these coordinates, the transmission may include weather data or other personal information. James Bond, send you current position to your friends or wife at home who may follow you at the computer screen. Furthermore, APRS may be operated via satellite and the space station ISS, and all that with a rather small investment.
At this site, I would like to explain how to start with APRS with simple means, how to do it and where to get the software and hardware, considering my own experiences as a beginner. Myself, I am not the ultimate APR specialist at all, being just a few months old with this new fashion in the air. But I hope, due to my recent experiences, I may be able to offer some help to APRS beginners.
As with most hobbies, you may start with € 0.00, provided you are in the posession of a 2-meter rig and a computer. I suppose most radio amateurs own that type of equipment nowadays. Just to get a fair idea about APRS for zero investment you can do the following:
- Download the APRS software UI-View at www.ui-view.com
- possibly a suitable map of your areas (www.aprs.de for Central Europe, other areas
- do the setup in UI-View
- Adjust your 2-meter rig to 144,800 MHz (at least here in Europe)
- ready to go
If you have not operated a packet radio, you will not have any other software. You probably own the necessary hardware, that is the soundcard of your computer (see FLEXNET). The TNC (Terminal Node Controller) is a piece of hardware and / or software that is comparable to a modem executing the communication protocol AX.25 and being connected between your computer and the transceiver.
Setup of UI-View
Before starting the actual setup you have to unpack the zip file and install the program according to the installation instructions. After successful installation, the individual setup of UI-View has to be done. Opening the pulldown menu "Set up" At the top of the program window you will see the 2 submenus Comms Setup and Station Setup. For beginners, only these two sub menus matter. The other setup menus are only for advanced and special operations.
If you own a TNC, adjust the settings as above or according to your baud rate setting between computer RS-232 and TNC (not the radio!). I do not have a TNC and you wish to use your soundcard, then you have to adjust the host mode window to FLEXNET. More details for FLEXNET use see below.
Please read the help which carefully during the first setup. TNCs.Opening the Button Setup Next to the host mode window, you can see the different types of TNC equipment. Using the TNC2 you should choose the Button TF. You might have to change the position inside the TNC to get it running. Myself, I am using the DSP-2232, I have adjusted it to KISS and Easy Setup PK (alike for all AEA products like the PK-232, PK-900 etc.). If you have made any adjustments carefully, the TNC interface should be running now, and you should be ready to receive packets or even see the station at your map. Sometimes it is necessary to restart UI-View in order to enable the COM port (RS-232) correctly.
The next step would be the Station Setup. There are, you have to leave your calls and your own coordinates, the rest of the inputs you leave as they are, at least for the beginning. After pressing the OK button, everything should be running ok. Better you restart UI-View another time. For the initial tests you may enter the interval 1 (minute) into the "Fixed" window, that’s, you want to send a packet every minute. You can also initiate the packet transmission by pressing the F9 key. For normal operation as a fixed station and 24-hour operation, it would be appropriate to 15. If all APRS stations would use the 1 minute interval, the network would soon collapse because of traffic overload. Furthermore, use the beacon comment for only essential information. Remember: the longer the packet, the smaller the packet. There is a rule: double the packet length equals 1/4 reception probability. The proper entry of the coordinates is very important, use exactly the same format as shown below. Most beginners oversee that, and station setup refuses the acceptance.
After pressing the OK button the packet wants to be sent out like this:
19: 47: 11T DK5EC>APU25J, TRACE3-3 port = 1:
= 5042.15N / 00714.82E-Karl in Koenigswinter
You may follow the transmission watching the monitor window below the map.
Your map should look like this, after some time receiving packets:
At the above map you see a lot of stations using different symbols. Yo may find trucks, cars, digipeaters, fire trucks, what ever you like. One time I caught a prison, the radio club chose the "grid" symbol, at my screen it looked like a prison cell window. Even a restroom (WC) is available. You may choose the symbol for your own station by opening the station setup and change the parameter "symbol". For my fixed computer I chose "Home", for my weather station "WX" and for my bycicle the bike.
As I mentioned above there are plenty of maps available on the APRS internet sites, for Europe www.aprs.com would be recommended. Some maps came with UI-View, and for a start, the Europe map might work. But you want to be the one in your area. And soon the map wants to be filled up with so many stations of your area that you can not differentiate them anymore. It is advisable to load a map of your country, state or province. The above map covers an area of about 400×400 km. But even here, especially in the more populated areas of Frankfurt or Ruhr region, there are too many stations to keep them apart. Loading another map of the appropriate area of my area aorund Bonn, I can see all stations.
If you can not find a map of your area or city at the internet, you may use a simple paper map (city map). You should use a scanner to make an electronic version of this map, and store it as a .jpg or. gif file. Now, you have the exact coordinates which correspond to the upper left and the lower right corner of the map, into an .inf file. The above file has the file name bonn.gif, and the corresponding file with the coordinates is called bonn.inf. The content of bonn.inf is:
Both files have been uploaded to the MAPI directory of UI-View. In the above example, the first to the area of Geilenkirchen, the second to the area of Nassau (not Bahamas, but hillbilly area of Westerwald). I scanned the paper map of my home village Koenigswinter, took my GPS receiver and went to the corresponding corners of the map by bike, and posted the coordinates. Back home I entered the coordinates into koenigswinter.inf.
In case you do not find a suiting map, you can generate any map with the help of www.aprs.fi by yourself. Display your desired map and scale at www.aprs.fi, click on top arrow, then you will get a full screen map. Move your mouse pointer into the left upper right corner, and note down the coordinates. Then make a screen shot, you may cut any unwired frames with the help of MSPaint if necessary, and store it as a .jpg file. Now write the .inf-file as described above, entering the coordinates.
Operation with the Soundcard
In TNC, or your TNC is not ready to run in hostmode or KISS, you can download a free TNC as a software package at
Download the two files flexnet32.zip and soundmodem-flex.zip, unpack and install them into the same directory, say C: flexnet . The following screen shot shows the necessary adjustments:
First you have to open soundmodemconfig.exe and adjust your sondmodem. it should leave the default settings as they are. When opening flexnet.exe you should see the soundmodem after opening the menu Tools / Parameters. In my setup you recognize two modems since I have another modem driver for a simple hardware modem AS52 which works with Flexnet.
If you have any problems with the sound card, you have connected the loudspeaker or headphone output of the radio to the line or microphone input of your sound card. Check your Windows settings Volume control / Options / Properties / Recording. Transmitting packets via the sound card also works fine with the line output, but you have to make some effort to handle the PTT function. There are many solutions for that problem available in the internet. I am using flexnet with my notebook and the small modem AS52 when going mobile by car. The modem has the PTT function included. Going mobile / portable on foot or bike I got another solution, see details below.
Particular Properties of the APRS Protocol
The APRS protocol is based on the normal packet radio protocol AX.25 but includes some extensions for the APRS digipeater functions. Those extensions are performed by UI-View and are not part of a normal TNC. The TNC has been to be operated in KISS mode. With KISS, most of the AX.25 functions of the TNC are deactivated, and the TNC is operating as a passive modem without protocol functions. The protocol intelligence is performed by the host, that is, the UI-View software. UI-View is the APRS protocol features.
The packets are sent out as so-called UI packets. UI packets are never acknowledged, which are likely to be received and which packets are expected to be received at this frequency. The protocol specialists call that mode broadcast or connectionless service (CLS). The contrary of this operation is the connection oriented service (COS) which is used for the acknowledged information exchange to a single communication partner. COS is actually the normal operation mode in packet radio, when using the normal packet mailboxes.
In my Station Setup above I entered "APRS" into the Unproto address window as the adressed station and WIDE3-3 as digipeater. "APRS" may consist of any other letters or numbers not exceeding 6 characters. If I do not enter anything as a digipeater, then my packet will be received only by APRS stations in my neighborhood, that is, in reach of the 2-meter signal. Digipeater or relays, I would not like to call it a digipeater or a digipeater call. All digipeaters react to the calls WIDE, TRACE or RELAY and process the received packages. My setup with WIDE3-3 triggers now the following: my station transmits the APRS and digipeater WIDE3-3. All digipeaters in my reach will process this package and retransmit it as APRS, WIDE3-2. More distant digipeaters, most likely out of my 2-meter reachability, want to receive this digipated packet and retransmit as APRS, WIDE3-1. Even more distant digipeaters wants to retransmit the package once more. Ohter digipeaters wants to receive this packet, but will not retransmit it, because the counter is now down to WIDE3-0. Anyway, with WIDE3-3 I might cover an area of 150×150 km or more. I received packets from station using WIDE7-7 all the way from Great Britain. But dont’use WIDE7-7 except for a test purposes because WIDE7-7, the channels would hopelessly be overloaded with digipeated packet waste.
WIDE3-3 happens with TRACE3-3, but here the digipeaters add their call signs to the address field. With that feature you can follow the route. Digipeater call signs and put their own call sign when retransmitting the packet. Anyway, to retransmit 7 call signs blows up the packet length, diminishing the reception probability.
In case the range of WIDE7-7 is not enough or you, you can book into any region of the world by using TCP / IP and the Internet. Certain digipeaters, in my area it is DB0LJ-3, allow access to and from the internet. It would be no problem to make my position available to the New York APRS network. (Most probably nobody would be interested in anayway and would not see me on the New York map.). If there is no APRS digipeater nearby you, you can reach them by using the local packet repeater and then entering the callsign of the APRS digipeater. I have not tried myself because of the TCP / IP and repeater features. However, many users do not like the Internet and Radio APRS network because of additional traffic load. But to try it just for test it might be fun. The APRS traffic of New York or Tokyo or Germany, the corresponding repeater internet addresses, like www.db0lj.de, and having your radio switched off.
Sometimes you might recognize some funny characters in the monitor window instead of the normal coordinates. But the stations are positioned at the right place of your map. UI-View offers the feature to transmit the coordinates in a compressed format (see Station Setup "compressed beacon"). The Kenwood transceivers may also transmit a compressed format called MIC-E, reducing the packet length to a minimum. Above I mentioned already, the packet length is reduced by 4 times.
A Weather Station using APRS
The above-described features you get for free are the basic equipment as a radio amateur or listener. Last time I managed to divert € 170.- from my paycheck, and I bought myself a weather station WS 2300. Most big electronic stores sell those things for about € 200.-, I bought mine via eBay for a little bit less.
The WS 2300 features everything you need, that is, sensors for temperature, air pressure, rain and wind, which have to be mounted outside the house. You may get detailed information about my new toy at http://www.heavyweather.info/.
This gadget features a RS-232 interface and software, enabling a connection to UI-View. However, you have to take certain facts, it took some time to overcome all the problems. What do you need to do for a weatherman for the APRS network? Here is the answer (at least how I did it):
– Weather Station WS 2300
– Software update for PC HeavyWeather 2.0 beta, download at www.heavyweather.info
– Software UI-View32, version 1.84 or above
– Software UI-Weather, download at www.apritch.myby.co.uk/uiweather.htm
Attention: the documentation is an additional file
– HeavyWeatherPublisher software, if you wish to send it to the weather servers in the internet at www.heavyweather.info
All the software is freeware, except UI-View32. It does not work with the free 16bit version of UI-View. The whole package runs as follows: the software Heavyweather loads the weather data from the WS 2300 via the COM port and saves them in the file currdat.lst. The software UI-Weather converts these data into a format suitable for UI-View32 and saves the converted data into the file wx.txt. Now you have the appropriate directories and file names in UI-View32 Setup / WX-Station Setup and UI-Weather in order to make them known to each other. My adjustments are as follows:
The APRS network, depending on the WX station Setup Timer Beacon Interval / Radio. The weather station appears on the map as a blue dot with the letters WX. By clicking this button opens with all the weather data of this particular station.
Below you see the screen shot of UI-Weather which left the software of the WS 2300 to UI-View32. This software thus saves all received data of all weather stations and can display these data in a diagram covering a 24h period. So the graphs of the earlier days may be displayed. And that is all freeware!
APRS as mobile and portable station
Whatever James Bond can do, (DK) 005 (EC) has been doing it now for several months, and all that without the support of MI5. At least concerning the use of location tracing tools. As you can see in the above maps, some of the stations are presented as cars, that is, mobile stations. Clicking on one of the mobile symbols. Another window showing some information about the current speed and direction of this car. The same thing goes for walkers and bike riders. As a mobile station, however, you have to invest a little bit in special hardware. Definitely, you will need a GPS receiver, you can buy this for about € 100 (GPS Mouse). You also need a mobile TNC which may be part of the following equipment:
– Notebook with Flexnet
– PAD with Flexnet
– transceiver with a built-in TNC function
– TinyTrack (microcontroller)
The first two types are available with the suitable APRS software or sound card TNC. You have to connect the GPS receiver to the notebook or PDA, to configure the APRS software, do the necessary cabling for the audio and PTT connection between transceivers and the computer, and it should work. Unfortunately the notebooks or PDAs only offer 1 RS-232 (COM port). That is all right, if you are using Flexnet and the sound card, this is the RS-232 is available for the GPS connection. However, if you are using a TNC or modem, they have to be connected to this single RS-232, too. There are two solutions for that problem: Either you use a USB / RS-232 converter cable for your GPS, or you build yourself a small adapter, the out of a few plugs and diodes enabling the simultaneous use of a RS-232 connector for the TNC / modem and the GPS. The latter is described in the UI-VIEW help functions or manual.
TNC function, like the Kenwood TM-D7000 for car handheld or handheld TH-D7 for portable operation. However, that would be an additional investment of about € 500 – 700.-. You will find plenty of information about these transceivers in the Internet at the APRS sites, how to connect them with the GPS receiver, the setup etc..
You have already spent a lot of money on your mobile or transceiver. The less expensive solution would be the TinyTrack, a small module of a micro-controller, some LEDs and other passive parts, about the size of matchbox. This module converts the NMEA signals to the GPS receiver into the APRS data and sends them as true AX.25 audio signals, including PTT function, to your transceiver or mobile phone. You just connect the TinyTrack and the microphone input of your transceiver. The module has to be connected to the RS-232 of your home computer, entering your call sign and beacon text. You may change between two configuration settings with a switch. I use different settings when using the car or my bike. You may only send APRS packet with this module and can not receive. But not having a display available anyway while riding the bike.
TNC feature or the TinyTrack. Finally, considering the price of $ 500.- and owning a duoband handheld (which I harldy use) I decided in favor of the TinyTrack. I bought my TinyTrack via the internet for about $ 30 as a kit, hence shipping costs of $ 9.-. You may therefore get it in the big ham radio stores, but for double the price, at least here in Europe. Do not be afraid to assemble the module yourself, I have not seen any SMD parts.
Look up for more information at http://www.byonics.com/.
The TinyTrack looks like this and has been included with the included configuration program.
Once in a while I take my TinyTrack and GPS receiver along for a bike ride. The whole world now can trace my route, riding along the Seven-Mountain Street, take a turn to the right into the Meadows Street. In case the whole world is not interested in my bike ride, I can trace the whole ride at my home computer after coming home. In order to do that I have to click on my mobile symbol and set it to "trace" and "Logging", I start the bike ride. Coming back home I now can replay my bike ride with different time scales loading my home made area map. Jamboree-on-the-air and other occasions are the highlights of this feature at ham radio meetings.
APRS via space stations and satellites
APRS may be operated via the International Space Station (ISS), the APRS satellite NO-44 or PACSAT AO-16. In the olden times I have seen many APRS stations using the good old MIR. Since space communication is one of my other hobbies, I am more concerned with doing that type of communication. I am interested in my space activities, you may have a look at my AMSAT publicateion "Amateur Radio via Satellites and Space Stations". Actually, an amateur radio station equipped with the usual simple transceivers and antennas may participate in space communications. There are quite sophisticated satellite tracking programs available showing the exact times of the passages of the space objects in excellent graphics presentation, most of them as freeware. I am using PCSAT32 which, besides the graphical display with world of area maps, so controls my antenna rotor system and my transceiver’s frequencies. Further details you will find at the above AMSAT page.
Teh signals of the ISS and NO-44 are rather strong so I can work them with a good vertical antenna. That goes for mobile stations alike. Myself I have not managed it with my handheld, it can only do 2 W power, but other handheld owners have done it. However, the ISS and the satellites operate as normal digipeaters without the features of WIDE and TRACE, and have the RSAISS-3 (for ISS), PCSAT-1 for the NO -44 and PACSAT-1 for the AO-16. Further restrictions exist. The NO-44 seems to have trouble with the batteries, and you can only work it daytime when there is enough sunligt available for the sun sails for this bird. The ISS is not always on the air with its packet transceiver. The most reliable satellite is AO-16, but you might need additional equipment for it. It also transmits to transceivers like the ICOM 821. Furthermore, the AO-16 is transmitting in PSK modulation, whereas normal modems only do FSK modulation. Because of that, normally I am the only operator on AO-16. Anyway, its always a nice feeling watching the ISS re-transmitting my position so that 1000 or more European stations can receive it.
At the picture below you can see the UI-VIEW screenshot while monitoring the NO-44. There is a freeware software addition for UI-View32 called pcsattlm.exe (download www.ui-view.com) showing the actual orbit and some telemetry. I took that screen shot when the batteries were still ok, nowadays the parameters Batt A and Batt B are below zero.
APRS information from DK5EC live via Internet
The program UI.-View has some other nice features, especially for those having a DSL connection into the internet. Via File / Internet Time Client you can get the precise time, your system clock is automatically set. I need precise time especially for my satellite activities.
A great feature of UI-View is the built-in HTTP server function. When activating File / WebServer, you have an HTTP server running on port 80, including at APRS web page. by typing the adress http: // localhost in your internet browser. APRS stations in aphabetical order. Clicking on the station you get more detailed information including 3 maps of different scales showing your position. At my page dk5ec.dyndns.org you can even see a QTH. The maps and the satellite picture is actually not available at my computer at home, it is rather a link to a map and satellite picture provider. The default links of UI-View to those maps do not work properly at my page. In case you have problems, I want to send these links to you.
Well, it could be nice if other OMs could get to your new http server and see all the sations which you presently receive via VHF. Firstly, they can not because they do not know your present dynamic IP adress. No problem, because you can assign your dynamic IP adress, that is, internet adress. Dyndns.org, I did it as dk5ec.dyndns.org, and all for free. I like this: If your computer is connected via DSL into the net, a short message to this DNS server is sent, telling it which IP address you presently own. The DNS server assigns this IP address to your domain callsign.dyndns.org, and anybody in the world can reach you via this internet address. To make this automatism work, you can download a small program from dyndns.org.
You can also send all of your received messages via VHF to APRS server in the internet. Then your information is distributed worldwide, and anybody can follow the active APRS stations in your area. My friend Rudolf, HS0ZER, VHF APRS net with his position, and I receive it via VHF, Of course I can not see it on my map, Thailand.
At my satellite page I have described how to use telemetry and APRS data from the ISS / PCSAT2, which I received on 70 cm, into the APRS server, and finally to the US Naval Academy. The PCSAT2 module is now ready to receive PCSAT2 data from all over the world.
APRS with Google Earth and aprs.fi
So Google Earth can display most of the APRS stations. Many hams so get the APRS position received via radio into the internet, see UI-View menu / Setup / APRS Server Setup. First, you should download the plug-in Google Earth KML from the page aprs.fi, see text window on the right. Then execute the file aprs.kml. Google Earth wants to open, and you should see "APRS, all targets in view" in the left text or menu window. All APRS stations of the selected region will be displayed. The mobile stations wants to be even dsiplayed with their track. Very impressing are airplanes and baloons with APRS on board, they are displayed with their altitude track in a 3-dimensional manner.
When going to www.aprs.fi, you may enter the APs station. If the station is on the road the site starts searching for this particular station and wants to display it at the corresponding map enviroment. When daddy is back on a business trip, I’d like to go back to school. (If Daddy wishes to) aprs.fi. And sometimes I want to find him parking in front of the supermarket, sometimes on a trip to Paris.
Well, now I am coming to the end of my explanations about APRS with many of its side features. There are a lot more possibilities, but time restricting my activities. Just start with the things I’ll explain at the beginning, and you’ll have a lot of fun. I hope to see you on my screen very soon!
Karl in Koenigswinter-Thomasberg
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