[OZAPRS] VK3 IGate / Zone system.

[Richard Hoskin]

This is a brief explanation of the way IGates are zoned in VK3, Mt Gambier
(VK5) & southern NSW (VK2).

 


Summary


To maintain high levels of efficiency and provide the widest possible
mobile
coverage on the APRS Network it is important to have a well-designed
network
based on a sound strategy. To this end the APRS network has been divided
into Zones, which are linked together by the internet through IGates. The
concept is similar to the GSM mobile phone network.

 

Details 

An IGate Zone is an area that is covered by a single RX Only IGate. The
Zone
extends a maximum of 2 hops (Wide Digipeaters) from the RX Only IGate. The
RX Only IGate is located as close as possible to the centre of the Zone.

 

The central TX IGate injects local internet APRS traffic into the RF
network
which propagates through the state's RF network. This reduces the possible
complications of hidden transmitters and timing issues allowing for a more
efficient RF system. It also means that data entering the system from any
one of the zones RX Only IGates is propagated through all other zones via
the central TX IGate. This again reduces network traffic while providing a
mechanism which allows the APRS users data to propagate through the RF
Network.

 

An IGate Zone is defined in detail in the document 'APRS Network Design
for
VK3'. For an explanation on Wide Digipeaters read the document 'APRS New
User Path Information Guide' 

 

Traffic levels are the greatest limiting factor in the size of the IGate
Zone.

 

To prevent packet duplication and network looping problems, (that very
quickly overload the local RF network) only one RX Only IGate per Zone is
used. It is also much more cost effective to have only one IGate in a
zone. 

 

The RX Only IGates will also function as a local message gateway which RX
and TX local APRS messages for the area. The coverage area of the Local
message zone is considered to be a maximum of two hops from the local RX
Only IGate. The local RX Only IGate shall have a path of APRS via "the
Local
Wide Digi",WIDE.

 

APRS 'Wide Digipeaters' are currently programmed to digipeat the alias's
RELAY, WIDE, TRACE, INETZ[x], WIDEn-N, Tracen-N.

 

Victorian Zones

 

Victoria has been divided into 6 IGate Zones; 5 Zones operate RX Only
IGates
and 1 Zone is the main State TX IGate as well as the local RX IGate

 

The IGate Zones are listed below.

 


IGate Zone

IGate Callsign

Designation

RX Coverage Area

APRS Digipeaters Covering Area


1

VK3SB-1

TX/RX

Melbourne, Ballarat, Geelong

VK3CV-1, VK3RMD-1, VK3RBU-1, VK3JFK-1 (VK3ROW-1)


2

VK3JTM-5

RX Only

Western Victoria, South Eastern South Australia,

VK3RPG-2, VK3SSS-1, VK3RMK-1, VK5JFK-1, VK3KAY-1


3

VK3JFK

RX Only

(Backup TX)

North Central Victoria, Southern NSW

VK3RMG-1, VK3YWY-1, VK3RCV-1, VK3ECH-1


4

VK3VHF-1

RX Only

Gippsland

VK3ZV-1, VK3RGI-1,VK3REB-1, VK3BLE-1, VK3VHF-1


5

VK3KAW

RX Only

North East Victoria, Southern NSW

VK3RGR-1, VK3RAW-1, VK2RBY-1, VK3RLE-1, VK3HJQ-1


6

VK3WRM

RX Only

North West Victoria

VK2RBX-1, VK3RON-1

 

 

Cheers

Richard

VK3JFK

 

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