In Australia, VHF is the most popular band for APRS, using the following convention:
| Band | Frequency | Mode | Digipeater Path |
|---|---|---|---|
| 2 metres | 145.175 MHz | FM 1200 bps AFSK | WIDE1-1,WIDE2-1 |
For HF bands, see HF Setup & Guidelines.
APRS is designed to convey local real-time information. As such, minimising the amount of non–local traffic over radio is important for avoiding collisions, which prevents stations from communicating.
Please use these recommendations to maximise APRS performance across the entire Australian VHF network:
Mobile Stations
MOBILE stations should use the following configuration guidelines.
- DO set your beacon rate to a MINIMUM of 60 seconds. (The preferred rate is 120 seconds for mobiles)
Why? Because the APRS frequency is a SHARED resource. Beaconing too frequently “hogs” the frequency so that nobody else can get in. If you have SmartBeaconing available in your tracker, USE IT. SmartBeaconing adjusts your beacon interval based on your speed – the faster you are travelling, the more frequent your beacons. - DO set your path to WIDE1-1,WIDE2-1. This will ensure your APRS setup will work throughout Australia.
Note that in some areas WIDE1-1,WIDE2-2 may be required; any state–specific information would take precedence. - DON’T use any of the following paths – RELAY, WIDE, TRACE, TRACEn-n.
All of these digipeater aliases are obsolete, and are being progressively phased out across the network - DON’T set a mobile station up as a digipeater of any kind.
Home / Fixed Stations
Generally, the following guidelines apply to a fixed/home station.
- DO set your beacon rate to a MINIMUM of 30 minutes.
Why? Because the APRS frequency is a SHARED resource. Beaconing too frequently “hogs” the frequency so that nobody else can get in. Besides – your house isn’t moving, so there is no need to refresh your position as often as a mobile station does. - DO check your state page to find out the path to use as a fixed station
Why? Each state has implemented slightly different methodology for fixed station beacon paths, in order to optimise the network availablility for everyone.
- DON’T use any of the following paths – RELAY, WIDE, TRACE, TRACEn-n. All of these digipeater aliases are obsolete, and are being progressively phased out across the network.
- DON’T use excessive transmission power. 10–20 watts is more than enough.
- DON’T put up a WIDE digipeater unless you truly have wide coverage and there are no other WIDEs in your area, and unless you plan to let it run 24 hours a day, 7 days a week.
Why? The APRS network infrastructure needs to be carefully co-ordinated to ensure it remains effective. Each state has a co-ordinator or co-ordinating group that has overall visibility of the network, and can determine whether digipeaters will help or degrade the existing network. WIDE area digipeaters also operate a dedicated TNC running the UIDIGI firmware. If you think you meet these conditions, please contact your local region co-ordinator before setting up the digipeater. - DON’T set your station up as a Fill-In digipeater (WIDE1-1) if there is already one close by. If you think there is a requirement for a Fill-In digipeater, please contact your local region co-ordinator before setting up the digipeater.
- DON’T set your station up as an IGATE (i.e. DO NOT gate data from the Internet to RF). This will only create traffic loops and problems on the channel.
If there is no IGate serving your local area (i.e within 2-3 digipeater hops), or there is no APRS activity at all where you are, please contact your local region co-ordinator so we can integrate your area into the network effectively.
Background
To quote the founder of APRS:
SUCCESSFUL APRS: The success of your local APRS is not how many stations you see on your maps, nor how far away, but how reliably your mobile or handheld or portable station can communicate with others in the local area. There is a big difference. This fundamental principal should drive everything we do with APRS in our local areas.
RELIABLE APRS: Said another way, the more stations you see above about 60 to 100 or so in typical areas, the more packets you don’t see due to collisions and the less reliable your network is for local real-time APRS use.
Bob Bruninga WB4APR
For these reasons, the VHF network is generally configured to maximise the availability for mobile/portable stations. The amount of data transmitted from the internet to the VHF network is minimal, so as to allow the maximum amount of airtime for mobile trackers to send thier data into the network.