APRS – Build Your Station

What equipment do I need for APRS?

Well it really depends on what type of station you are interested in.  If you are interested in a fixed or base station you will need a transceiver and a terminal node controller (TNC).  Most any VHF radio base or mobile (used as a base) will work providing you have the right interconnection cables available to connect the radio to the TNC.

As for the TNC there are several equipment manufacturers such as Kantronics, AEA (Timewave), MFJ which are few of the major name-brands. One of the popular TNC’s used by VARC members is the opentracker which is available from Remember you will probably not need the most expensive TNC on the market.

The final major piece of equipment that you will need a personal computer that has APRS software installed on it.  There are a variety of APRS software to choose from on the market.  WinAPRS, MacAPRS, UIVIEW32, and Xastir for Linux are popular software programs available to amateur radio operators. The most used software is UIVIEW32 which can be found at When all of the equipment is properly connected and setup your station will then be ready to operate. Please refer to the diagram below for a visual presentation of how the equipment is connected

If you you are interested in going mobile or portable, then you will want  to add a Global Positioning System (GPS) unit that will need to be connected to your TNC.  The GPS will allow you to report your position to other stations as you move about.

So now you’ve learned that you need a TNC, Radio, Computer, and GPS.  Wouldn’t it be convenient if there was equipment that had every in one package? Well there is…  Kenwood one of the major radio manufacturers who is currently the only manufacturer with such a package. The the Kenwood radio model numbers  TH-D7A(G) (Handheld Radio), TM-D700A and TM-710A (Mobile Radios). The D7A is a dualband portable with simultaneous receive and a built-in TNC. The D700 and D710 is similar but in a mobile version.

Here is some APRS information you should consider:

Digipeater (digi) – a “repeater” used to transmit / receive packet data. A digi is crucial to APRS networks. Beacon – transmission containing data like callsign, coordinates, course, speed, altitute or elevation, and any comment text. The VARC digi operates as W4VLD-1.

IGate – this is a portal to the internet. Some IGates are digipeaters. IGates are typically two-way streets. When the IGate reveives a beacon, it will feed it to the internet. Path(unproto) – this determines how your beacon is received and sent through the network.

The primary APRS Frequency is 144.390 MHz simplex.  The  TNC Packet Baud usually set to 1200 baud.  The TNC Packet Path is usually set to (unproto) – fixed WIDE1-1,WIDE2-2. mobile/portable WIDE1-1,WIDE3-3. RELAY,WIDE IS OBSOLETE.



The picture below represents a typical station.


The picture below represents a typical mobile or portable APRS tracker. The Garmin GPS on the right with its antenna mounted on top of the Alinco mobile radio. The Kantronics KPC3+ TNC is mounted on the bottom plate below the radio.  Now just connect a VHF antenna to the radio and provide 12 volts and the station is ready.


More information can be found on the web or you can contact the VARC for help from one its APRS active members.