APRS

THE LEAST YOU NEED TO KNOW

APRS, or Automatic packet reporting system is basically a packet system that relays your position through a digipeater and can also be sent through the internet so that people can see where you are and can also be used to send messages.
Programes such as WinAPRS and UI-View are very good APRS programes and Ui-View can be setup to be a digipeater and a IGate. For making UI-View a digi all you need is a host programe such as AGW or BPQ.
The Kenwood TH-D7 transceiver is a great little device if you are serious about APRS and can be used with a GPS for mobile operation. For home all you will need is a Computer and a TNC. You can enter your position in manually so a GPS is only needed when you are on the move.

DIGIPEATERS

In APRS the repeaters are called digipeaters and they relay the information onto the next digi and people within this area will recieve your callsign and position. It is alot similar to a normal packet node but it is retransmitted automaticly.

DIGIPEATING PATHS

When you begin using UI-View or any other programe you will proberly have to specify what is called a digi path or unproto address, this is the path that your transmission will take. For example if you send a message RELAY,WIDE then it will go through the first digi, and be resent as yourcall,wide. From here it will goto the next digi and be retransmitted again, but not a third time. You can send RELAY,WIDE,WIDE which will be sent through the first 3 digi's, or for even loger coverage you can send RELAY,WIDE5-5 this means that it will be relayed 6 times, first the relay then the wide5-5 then wide5-4 and so on.

UI-View

PING

If you dont know if a station is on then you can do what is called a ping. This is where a message is sent via a specified path (usually relay,wide) and if they are on then it will come back with the path to that station. It can also tell you how fast the path is, by the time that it takes to come back.

PCSAT

On the 30th of September 2001 the sattellite PCSAT was launched and for people in remote areas it can be heard on 145.825Mhz but to send packets through it you must send a compressed packet, this can be done with a add on for UI-View but you will need a registration number.
The uplink and downlink frequencies are:

Base station 50 watts 9600 baud 435.250Mhz, and the packet must be sent via W3ADO-1,SGATE,WIDE
walkie-talkie 5 watts 1200 baud 145.825Mhz, and the same as above.
Mobile 50 watts 9600 baud 435.250Mhz, and the same as above.
All downlinks are on 145.825Mhz 1200 Baud

MAPS

APRS maps can be made very easily, all you need is a picture of a map, in GIF or BMP format for UI-View. Then you make a INF file and put in first the GPS points for the top left of the picture then the bottom right. Then at the bottom the name that will appear in the list of maps. e.g.

37.30.45S, 146.30.00E
38.00.00S, 147.00.00E
test map
I have scanned in most of the Vicroads RACV book and made maps out of them so if you are after a specific area inside of Victoria then I would be happy to send you a map of your area.

LINKS

  1. PCSAT homepage
  2. Winpack and UI-View
  3. For UI-View maps??
  4. My personal homepage
  5. Back to the club homepage
  6. All you need to know about packet radio
For any questions please send a e-mail to me. I would be happy to answer any.