[Vk1tac] Re: Ginini 2 metre services

[Neil Pickford]

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----- Original Message -----
From: "Paul Thomas Elliot" <pkbelliot@bigpond.com>
To: "Mr Gilbert Hughes" <ghughes3@bigpond.com>
Sent: Monday, 13 January 2003 12:46 AM
Subject: Re: Ginini 2 metre services


Gilbert, here are a few of my thoughts.

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		Mt Ginnini and Packet Use

Mt. Ginnini being an elevated site remote from Canberra makes it ideal as a DX site. The low site noise adds to the usefullness of this site in this mode.

Packet radio I think is characterised by relatively short paths to increase signal strength and paths without multipath signals. In short, a service which supports fixed stations with good solid strengths.

APRS is essentially a packet service for mobile stations. These stations are usually vehicle based.

Though  Mt. Ginnini is an elevated site it is remote from most major roads. There are some minor roads in the vicinity but these carry very little traffic. The roads of importance are the Hume, Federal, Barton and Monaro Highways. Ginnini does not serve any of these well. Also, I believe the nature of the APRS service would not be well served by the use of Ginnini for APRS. 

APRS is served by a number of "Wides" which can talk to each other. Currently the local "Wide" is in Canberra and it does a reasonable job. There is another in Wagga and it also does a reasonable job. The Canberra and Wagga "Wides" exchange data via the internet. There are plans to place another "Wides" in Goulburn and another towards Cooma. With another somewhere in the Yass area I believe would provide excellent APRS coverage throughout the Southern part of N.S.W.

If an APRS "Wide" were placed on Ginnini it would be able to hear all the other "Wides". It would certainly generate a lot of traffic but I think it would not necessarily provide the best service. We would have a network which is operating over a large area but we would have little control over the network.

This would be akin to the situation which Telstra Mobiles are experiwncing. Telstra Tower oversess a number of other sites and causes problems with the frequency re-use which is a fundamental principle of the cellular network. As PARS is a Single Frequency Network(SFN) it would suffer from the same problems if an APRS node on Ginnini was able to be heard by all the other nodes.

What to do with packet? This is a bit of a problem. Packet seems to have been adversely by the proliferation of the Internet. I do not use packet (apart from listening to APRS) so I cannot give an informed opinion. However, I don't think I would be likely to become involved in Packet as my data needs are met by the Internet.

Perhaps there is a need to combine Packet and IRLP. "Wormholes" exist but are under a bit of a cloud because of the perception that they are not allowed under the current regukations. Perhaps if an IRLP type of connectivety was established for Packet then this problem would go away. 

Speed is the other blockage which is causing people to move away from Packet in favour of the Internet. Currently we support 1200 and 4800 (not sure whether this is bps or baud) an dther is a commercial push fro transciever makers to support 9600 though there is little gain over 4800. These speeds pale into insignificance when compared to what is available over a standard telephone line. There appears to be some problem in providing a truely high speed RF solution which suits the Amateur community. High speed RF links have been around for some years but the Amateur community has not developed even a rudimentary high speed link. It appears that the reading of the literature seems to show people are very concerned with producing spectrum efficient designs which are hard to produce which leads to them not being developed.

I think we should take the aproach of producing something which is simple, with an efficiency which is suitable for the band it is used in and easy to produce. The alternative is to use existing technology in one of the ISM bands and combine this with a high speed Internet connection. 

Apart from that it is difficult to say what should be done with packet. I would be loath to remove the packet repeater from Ginnini unless something was to take its place. I am of the view that while it is in place and we have overcome the engineering problems associated with its existence there is little to be gained in removing it. Though the usage is small the current repeaters are providing a service. If they are removed and not replaced with something else I believe that we will become somewhat spoiled. We will become used to having a simple setup and will find it difficult to provide access for future services (whatever thay may be).

Paul Elliot
13/1/2003.

Therefore I would reccomend the following:

1) APRS not be sited on Mt. Ginnini.

2) The Packet service on the mountain be left as is.

3) A review be undertaken of the PAcket service with the view of providing a future direction for the service. I would envisage this would be an Australian wide review.

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